Improved UI and enhanced expense creation

Updated the UI across all screens (Login, Dashboard, Account Selection, Expense Details, and Creation) with a more modern, card-based design and improved layouts. Expense creation now includes: - Real-time split validation to ensure shares match the total amount. - An "Equal Split" shortcut for quick allocation. - Support for optional descriptions and multiple file attachments. - Strict save validation. The `MainActivity` now supports edge-to-edge display, and the `AccountDao` includes a new query to fetch accounts by ID. Added `material-icons-extended` dependency for enhanced iconography.
Implemented expense creation functionality.
2026-03-04 16:38:40 +01:00 · 2026-03-04 14:55:31 +01:00 · 2026-03-04 14:22:21 +01:00 · 2026-03-04 14:16:45 +01:00 · 2026-03-04 12:28:12 +01:00 · 2026-03-04 11:56:57 +01:00
30 changed files with 1730 additions and 220 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -1,11 +1,36 @@
+# Build artifacts
+bin/
+gen/
+out/
+build/
+app/build/
+
+# Kotlin / Java
 *.iml
-.gradle
-/local.properties
-/.idea
-.DS_Store
-/build
-/captures
-.externalNativeBuild
-.cxx
+*.ipr
+*.iws
+.idea/
+.gradle/
 local.properties
-/app/build
+
+# Android Studio
+captures/
+.externalNativeBuild/
+.cxx/
+.navigation/
+
+# Keys & Secrets
+*.jks
+*.keystore
+*.p12
+google-services.json
+
+# OS generated files
+.DS_Store
+Thumbs.db
+
+# Log files
+*.log
+
+# Bundle/Release
+/app/release/
--- a/README.md
+++ b/README.md
@@ -0,0 +1,20 @@
+# ShAp-Planner
+
+ShAp-Planner is a **self-hosted app** for managing finances, tasks, and data within shared households.  
+The app is fully open source, lightweight, and can run on small devices like Raspberry Pi or older computers.
+
+**[Backend](https://git.miaurizius.de/MiauRizius/shap-planner-backend):** Go  
+**[Frontend](https://git.miaurizius.de/MiauRizius/shap-planner-android):** Android (Kotlin)  
+**[License](https://git.miaurizius.de/MiauRizius/shap-planner-android/src/branch/main/LICENSE):** [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/)
+
+---
+
+## Installation
+
+You can either build the app from source or download the apk _(will be available soon)_
+
+---
+
+## License
+
+This work is marked <a href="https://creativecommons.org/publicdomain/zero/1.0/">CC0 1.0</a>
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -61,6 +61,7 @@ dependencies {

    //Manually added
    implementation("androidx.datastore:datastore-preferences:1.2.0")
+    implementation("androidx.compose.material:material-icons-extended:1.6.0")

    val room_version = "2.8.4"
    implementation("androidx.room:room-runtime:$room_version")
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -1,9 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools">
-
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name="android.permission.INTERNET" />
-
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
@@ -12,19 +9,16 @@
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
-        android:usesCleartextTraffic="true"
+        android:networkSecurityConfig="@xml/network_security_config"
        android:theme="@style/Theme.ShapPlanner">
        <activity
            android:name=".activities.MainActivity"
            android:exported="true"
-            android:label="@string/app_name"
            android:theme="@style/Theme.ShapPlanner">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
-
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
-
 </manifest>
--- a/app/src/main/java/de/miaurizius/shap_planner/TokenStorage.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/TokenStorage.kt
@@ -12,13 +12,14 @@ class TokenStorage(context: Context) {

    private val prefs = EncryptedSharedPreferences.create(
        context,
-        "wg_token_prefs",
+        "wg_token_prefs2",
        masterKey,
        EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
        EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
    )

    fun saveTokens(accountId: String, accessToken: String, refreshToken: String) {
+//        println("Account ID: ${accountId}\nAToken: ${accessToken}\nRToken: ${refreshToken}")
        prefs.edit()
            .putString("access_$accountId", accessToken)
            .putString("refresh_$accountId", refreshToken)
--- a/app/src/main/java/de/miaurizius/shap_planner/activities/MainActivity.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/activities/MainActivity.kt
@@ -2,212 +2,85 @@ package de.miaurizius.shap_planner.activities

 import android.os.Bundle
 import androidx.activity.ComponentActivity
+import androidx.activity.compose.BackHandler
 import androidx.activity.compose.setContent
-import androidx.compose.foundation.background
-import androidx.compose.foundation.clickable
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.navigationBarsPadding
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.statusBarsPadding
-import androidx.compose.foundation.layout.width
-import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.lazy.items
-import androidx.compose.foundation.shape.CircleShape
-import androidx.compose.material3.Button
-import androidx.compose.material3.Card
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Text
-import androidx.compose.material3.TextField
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
+import androidx.activity.enableEdgeToEdge
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.tooling.preview.Preview
-import androidx.compose.ui.unit.dp
+import de.miaurizius.shap_planner.TokenStorage
 import de.miaurizius.shap_planner.UserPreferences
-import de.miaurizius.shap_planner.entities.Account
 import de.miaurizius.shap_planner.room.AppDatabase
+import de.miaurizius.shap_planner.ui.AppContent
 import de.miaurizius.shap_planner.ui.theme.ShapPlannerTheme
+import de.miaurizius.shap_planner.viewmodels.ExpenseCreationViewModel
+import de.miaurizius.shap_planner.viewmodels.ExpenseDetailViewModel
 import de.miaurizius.shap_planner.viewmodels.LoginViewModel
 import de.miaurizius.shap_planner.viewmodels.MainViewModel
-import java.util.UUID

 class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
+        enableEdgeToEdge()
        super.onCreate(savedInstanceState)
-//        enableEdgeToEdge()

        val prefs = UserPreferences(this)
        val loginViewModel = LoginViewModel(prefs, applicationContext)
-
        val database = AppDatabase.getDatabase(applicationContext)
-        val dao = database.accountDao()
-        val mainViewModel = MainViewModel(dao)
+        val accountDao = database.accountDao()
+        val expenseDao = database.expenseDao()
+        val tokenStorage = TokenStorage(applicationContext)
+        val mainViewModel = MainViewModel(
+            accountDao,
+            expenseDao,
+            tokenStorage
+        )
+        val detailViewModel = ExpenseDetailViewModel(
+            database.expenseDao(),
+            database.expenseShareDao(),
+            database.userDao(),
+            tokenStorage
+        )
+        val creationViewModel = ExpenseCreationViewModel(
+            database.userDao(),
+            database.expenseDao(),
+            database.expenseShareDao(),
+            tokenStorage
+        )
+

        setContent {
            ShapPlannerTheme {
-                val isLoggedIn by loginViewModel.isLoggedIn.collectAsState()
                val accountList by mainViewModel.accounts.collectAsState()
                val selectedAccount = mainViewModel.selectedAccount
+                val showLoginForNewAccount = remember { mutableStateOf(false) }

-                when {
-                    !isLoggedIn || accountList.isEmpty() -> {
-                        LoginScreen { serverUrl, username, password -> loginViewModel.login(serverUrl, username, password, mainViewModel) }
+                BackHandler(enabled = showLoginForNewAccount.value && accountList.isNotEmpty()) {
+                    showLoginForNewAccount.value = false
                }

-                    selectedAccount != null -> {
-                        DashboardScreen(
-                            account = selectedAccount,
-                            onBack = { mainViewModel.logoutFromAccount() }
-                        )
-                    }
-
-                    else -> {
-                        AccountSelectionScreen(
-                            accounts = accountList,
-                            onAccountClick = { account ->
-                                mainViewModel.selectAccount(account)
+                AppContent(
+                    accountList = accountList,
+                    selectedAccount = selectedAccount,
+                    showLoginForNewAccount = showLoginForNewAccount.value,
+                    onLogin = { server, user, pass ->
+                        loginViewModel.login(server, user, pass, mainViewModel)
+                        showLoginForNewAccount.value = false
                    },
-                            onAddAccountClick = {
-                                loginViewModel.logout()
-                            }
+                    onSelectAccount = { mainViewModel.selectAccount(it) },
+                    onLogoutAccount = { mainViewModel.logoutFromAccount() },
+                    onAddAccountClick = { showLoginForNewAccount.value = true },
+                    onDeleteAccount = { mainViewModel.deleteAccount(selectedAccount!!) },
+                    sessionState = mainViewModel.sessionState,
+                    onValidateSession = { mainViewModel.validateSession(selectedAccount!!) },
+                    onSessionInvalid = { mainViewModel.logoutFromAccount() },
+                    onExpenseClick = { expense -> println("Clicked: ${expense.title}") },
+                    viewModel = mainViewModel,
+                    detailViewModel = detailViewModel,
+                    creationViewModel = creationViewModel,
                )
            }
        }
    }
-        }
-    }
-}
-
-@Composable
-fun AccountSelectionScreen(accounts: List<Account>, onAccountClick: (Account) -> Unit, onAddAccountClick: () -> Unit) {
-    LazyColumn(
-        modifier = Modifier
-            .fillMaxSize()
-            .padding(16.dp)
-            .statusBarsPadding()
-            .navigationBarsPadding(),
-        verticalArrangement = Arrangement.spacedBy(12.dp)
-    ) {
-        item {
-            Text("Wähle einen Account", style = MaterialTheme.typography.headlineSmall)
-        }
-
-        items(accounts) { account ->
-            Card(modifier = Modifier.fillMaxWidth().clickable{ onAccountClick(account) }) {
-                Row(modifier = Modifier.padding(16.dp), verticalAlignment = Alignment.CenterVertically) {
-                    Box(modifier = Modifier.size(40.dp).background(Color.Gray, shape = CircleShape))
-                    Spacer(modifier = Modifier.width(16.dp))
-                    Column {
-                        Text(text = account.name, fontWeight = FontWeight.Bold)
-                        Text(text = account.wgName, style = MaterialTheme.typography.bodyMedium)
-                    }
-                }
-            }
-        }
-        item {
-            Spacer(modifier = Modifier.height(8.dp))
-            Button(
-                onClick = onAddAccountClick,
-                modifier = Modifier.fillMaxWidth()
-            ) {
-                Text("Anderen Account hinzufügen")
-            }
-        }
-    }
-}
-
-@Composable
-fun LoginScreen(onLogin: (String, String, String) -> Unit) {
-    var serverUrl by remember { mutableStateOf("") }
-    var username by remember { mutableStateOf("") }
-    var password by remember { mutableStateOf("") }
-
-    Column(modifier = Modifier.padding(16.dp).statusBarsPadding().navigationBarsPadding()) {
-        Text("Bitte anmelden")
-        Spacer(modifier = Modifier.height(8.dp))
-
-        //Home-Server
-        TextField(
-            value = serverUrl,
-            onValueChange = { serverUrl = it },
-            label = { Text("Server-URL") }
-        )
-        Spacer(modifier = Modifier.height(8.dp))
-
-        //Username
-        TextField(
-            value = username,
-            onValueChange = { username = it },
-            label = { Text("Nutzername") }
-        )
-        Spacer(modifier = Modifier.height(8.dp))
-
-        //Password
-        TextField(
-            value = password,
-            onValueChange = { password = it },
-            label = { Text("Passwort") }
-        )
-        Spacer(modifier = Modifier.height(8.dp))
-
-        Button(onClick = { if(serverUrl.isNotEmpty() && username.isNotEmpty() && password.isNotEmpty()) onLogin(
-            serverUrl,
-            username,
-            password
-        ) }) {
-            Text("Login")
-        }
-    }
-}
-
-@Composable
-fun DashboardScreen(account: Account, onBack: () -> Unit) {
-    Column(
-        modifier = Modifier
-            .fillMaxSize()
-            .padding(16.dp)
-            .statusBarsPadding()
-            .navigationBarsPadding()
-    ) {
-        Row(
-            modifier = Modifier.fillMaxWidth(),
-            horizontalArrangement = Arrangement.SpaceBetween,
-            verticalAlignment = Alignment.CenterVertically
-        ) {
-            Column {
-                Text(text = "Hallo, ${account.name}!", style = MaterialTheme.typography.headlineMedium)
-                Text(text = "WG: ${account.wgName}", style = MaterialTheme.typography.bodyLarge, color = Color.Gray)
-            }
-            Button(onClick = onBack) {
-                Text("Wechseln")
-            }
-        }
-
-        Spacer(modifier = Modifier.height(32.dp))
-
-        Box(
-            modifier = Modifier
-                .fillMaxSize()
-                .background(MaterialTheme.colorScheme.surfaceVariant, shape = MaterialTheme.shapes.medium),
-            contentAlignment = Alignment.Center
-        ) {
-            Text("Hier kommen bald deine WG-Kosten hin 🚀")
-        }
-    }
 }
--- a/app/src/main/java/de/miaurizius/shap_planner/entities/Account.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/entities/Account.kt
@@ -25,6 +25,9 @@ interface AccountDao {
    @Query("SELECT * FROM accounts")
    fun getAllAccounts(): Flow<List<Account>>

+    @Query("SELECT * FROM accounts WHERE id = :userId")
+    fun getAccountById(userId: UUID): Flow<Account?>
+
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertAccount(account: Account)

--- a/app/src/main/java/de/miaurizius/shap_planner/entities/Expense.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/entities/Expense.kt
@@ -5,18 +5,21 @@ import androidx.room.Delete
 import androidx.room.Entity
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
+import androidx.room.PrimaryKey
 import androidx.room.Query
 import kotlinx.coroutines.flow.Flow
 import java.util.UUID

@Entity(tableName = "expenses")
 data class Expense (
-    val id: UUID,
-    val amt: Double,
-    val desc: String,
-
-    val payerId: UUID,
-    val debtors: List<User>
+    @PrimaryKey val id: UUID,
+    val payer_id: UUID,
+    val amount: Int,
+    val title: String,
+    val description: String,
+    val attachments: List<String>?,
+    val created_at: Int,
+    val last_updated_at: Int
 )

@Dao
--- a/app/src/main/java/de/miaurizius/shap_planner/entities/ExpenseShare.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/entities/ExpenseShare.kt
@@ -0,0 +1,37 @@
+package de.miaurizius.shap_planner.entities
+
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Entity
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.PrimaryKey
+import androidx.room.Query
+import kotlinx.coroutines.flow.Flow
+import java.util.UUID
+
+@Entity(tableName = "expense_shares")
+data class ExpenseShare(
+    @PrimaryKey val id: UUID,
+    val expense_id: UUID,
+    val user_id: UUID,
+    val share_cents: Int
+)
+
+@Dao
+interface ExpenseShareDao {
+    @Query("SELECT * FROM expense_shares")
+    fun getAllShares(): Flow<List<ExpenseShare>>
+
+    @Query("SELECT * FROM expense_shares WHERE id = :shareId")
+    fun getShareById(shareId: UUID): Flow<ExpenseShare?>
+
+    @Query("SELECT * FROM expense_shares WHERE expense_id = :expense_id")
+    fun getSharesByExpense(expense_id: UUID): Flow<List<ExpenseShare>>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insertShare(share: ExpenseShare)
+
+    @Delete
+    suspend fun deleteShare(share: ExpenseShare)
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/entities/User.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/entities/User.kt
@@ -5,14 +5,16 @@ import androidx.room.Delete
 import androidx.room.Entity
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
+import androidx.room.PrimaryKey
 import androidx.room.Query
 import kotlinx.coroutines.flow.Flow
 import java.util.UUID

@Entity(tableName = "users")
 data class User (
-    val id: UUID,
+    @PrimaryKey val id: UUID,
    val name: String,
+    val avatar_url: String?
 )

@Dao
@@ -20,6 +22,9 @@ interface UserDao {
    @Query("SELECT * FROM users")
    fun getAllUsers(): Flow<List<User>>

+    @Query("SELECT * FROM users WHERE id = :userId")
+    fun getUserById(userId: UUID): Flow<User?>
+
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertUser(user: User)

--- a/app/src/main/java/de/miaurizius/shap_planner/network/APIService.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/network/APIService.kt
@@ -1,17 +1,54 @@
 package de.miaurizius.shap_planner.network

+import com.google.gson.annotations.SerializedName
+import de.miaurizius.shap_planner.entities.User
 import retrofit2.Response
 import retrofit2.http.Body
+import retrofit2.http.DELETE
+import retrofit2.http.GET
+import retrofit2.http.Header
 import retrofit2.http.POST
-
-data class LoginRequest(val username: String, val password: String)
-data class LoginUser(val id: String, val username: String, val role: String, val avatarUrl: String?)
-data class LoginResponse(val access_token: String, val refresh_token: String, val user: LoginUser, val wgName: String)
+import retrofit2.http.PUT
+import retrofit2.http.Query
+import java.util.UUID

 interface APIService {
+    // Account
    @POST("api/login")
    suspend fun login(@Body req: LoginRequest): Response<LoginResponse>
-
    @POST("api/refresh")
-    suspend fun refresh(@Body req: Map<String, String>): Response<Map<String, String>>
+    suspend fun refresh(@Body req: RefreshRequest): Response<RefreshResponse>
+    @GET("api/ping")
+    suspend fun ping(@Header("Authorization") token: String): Response<Map<String, String>>
+
+    // Expenses
+    @GET("api/expenses")
+    suspend fun expensesGet(@Header("Authorization") token: String): Response<ExpensesResponse>
+    @POST("api/expenses")
+    suspend fun expenseCreate(@Header("Authorization") token: String, @Body req: ExpenseCreationRequest): Response<ExpenseCreationResponse>
+    @PUT("api/expenses")
+    suspend fun expenseUpdate(@Header("Authorization") token: String)
+    @DELETE("api/expenses")
+    suspend fun expenseDelete(@Header("Authorization") token: String)
+
+    // Shares
+    @GET("api/shares")
+    suspend fun sharesGet(@Header("Authorization") token: String): Response<ExpenseSharesResponse>
+    @GET("api/shares")
+    suspend fun shareGet(@Header("Authorization") token: String, @Query("id") shareId: UUID): Response<ExpenseShareResponse>
+    @GET("api/shares")
+    suspend fun shareGet(@Header("Authorization") token: String, @Query("id") expenseId: UUID, @Query("idType") idType: IDType): Response<ExpenseSharesResponse>
+
+    // User
+    @GET("api/userinfo")
+    suspend fun userinfo(@Header("Authorization") token: String, @Query("id") userId: UUID): Response<User>
+}
+
+enum class IDType {
+    @SerializedName("share")
+    Share,
+    @SerializedName("expense")
+    Expense,
+    @SerializedName("user")
+    User,
 }
--- a/app/src/main/java/de/miaurizius/shap_planner/network/ComDataTypes.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/network/ComDataTypes.kt
@@ -0,0 +1,22 @@
+package de.miaurizius.shap_planner.network
+
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseShare
+
+// Login
+data class LoginRequest(val username: String, val password: String)
+data class LoginUser(val id: String, val username: String, val role: String, val avatarUrl: String?)
+data class LoginResponse(val access_token: String, val refresh_token: String, val user: LoginUser, val wgName: String)
+
+// Refresh-Tokens
+data class RefreshRequest(val refresh_token: String)
+data class RefreshResponse(val access_token: String, val refresh_token: String)
+
+// Expenses
+data class ExpensesResponse(val expenses: List<Expense>)
+data class ExpenseCreationRequest(val expense: Expense, val shares: List<ExpenseShare>)
+data class ExpenseCreationResponse(val expense: Expense, val shares: List<ExpenseShare>)
+
+// ExpenseShares
+data class ExpenseSharesResponse(val shares: List<ExpenseShare>)
+data class ExpenseShareResponse(val share: ExpenseShare)
--- a/app/src/main/java/de/miaurizius/shap_planner/network/RetrofitProvider.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/network/RetrofitProvider.kt
@@ -8,7 +8,7 @@ import retrofit2.converter.gson.GsonConverterFactory
 object RetrofitProvider {

    fun create(serverUrl: String): APIService {
-        val base = if (serverUrl.endsWith("/")) serverUrl else "$serverUrl/"
+        val base = if (serverUrl.endsWith("/")) "https://$serverUrl" else "https://$serverUrl/"

        val logger = HttpLoggingInterceptor().apply { level = HttpLoggingInterceptor.Level.BASIC }

--- a/app/src/main/java/de/miaurizius/shap_planner/network/SessionState.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/network/SessionState.kt
@@ -0,0 +1,8 @@
+package de.miaurizius.shap_planner.network
+
+sealed class SessionState {
+    object Loading : SessionState()
+    object Valid : SessionState()
+    object Invalid : SessionState()
+    data class Error(val message: String) : SessionState()
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/repository/ExpenseRepository.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/repository/ExpenseRepository.kt
@@ -0,0 +1,33 @@
+package de.miaurizius.shap_planner.repository
+
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseDao
+import de.miaurizius.shap_planner.network.APIService
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flow
+
+class ExpenseRepository(
+    private val dao: ExpenseDao,
+    private val api: APIService
+) {
+    fun getExpenses(token: String, forceRefresh: Boolean = false): Flow<Resource<List<Expense>>> = flow {
+        val cachedExpense = dao.getAllExpenses().first()
+        emit(Resource.Loading(cachedExpense))
+
+        if(cachedExpense.isEmpty() || forceRefresh) {
+            try {
+                val response = api.expensesGet("Bearer $token")
+                if(response.isSuccessful) {
+                    val remoteExpense = response.body()?.expenses ?: emptyList()
+                    remoteExpense.forEach {
+                        dao.insertExpense(it)
+                    }
+                }
+            } catch(e: Exception) {
+                emit(Resource.Error("Network Error: ${e.localizedMessage}", cachedExpense))
+            }
+        }
+        dao.getAllExpenses().collect { emit(Resource.Success(it)) }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/repository/ExpenseShareRepository.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/repository/ExpenseShareRepository.kt
@@ -0,0 +1,72 @@
+package de.miaurizius.shap_planner.repository
+
+import de.miaurizius.shap_planner.entities.ExpenseShare
+import de.miaurizius.shap_planner.entities.ExpenseShareDao
+import de.miaurizius.shap_planner.network.APIService
+import de.miaurizius.shap_planner.network.IDType
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flow
+import java.util.UUID
+
+class ExpenseShareRepository(
+    private val dao: ExpenseShareDao,
+    private val api: APIService
+) {
+    fun getShares(token: String, forceRefresh: Boolean = false): Flow<Resource<List<ExpenseShare>>> = flow {
+        val cachedData = dao.getAllShares().first()
+        emit(Resource.Loading(cachedData))
+
+        if(cachedData.isEmpty() || forceRefresh) {
+            try {
+                val response = api.sharesGet("Bearer $token")
+                if(response.isSuccessful) {
+                    val remoteShare = response.body()?.shares ?: emptyList()
+                    remoteShare.forEach {
+                        dao.insertShare(it)
+                    }
+                }
+            } catch(e: Exception) {
+                emit(Resource.Error("Network Error: ${e.localizedMessage}", cachedData))
+            }
+        }
+        dao.getAllShares().collect { emit(Resource.Success(it)) }
+    }
+
+    fun getShareById(token: String, shareId: UUID, forceRefresh: Boolean = false): Flow<Resource<ExpenseShare>> = flow {
+        val cached = dao.getShareById(shareId).first()
+        emit(Resource.Loading(cached))
+        if(cached == null || forceRefresh) {
+            try {
+                val response = api.shareGet("Bearer $token", shareId)
+                if(response.isSuccessful) {
+                    response.body()?.share?.let { remoteShare -> dao.insertShare(remoteShare) }
+                }
+            } catch(e: Exception) {
+                emit(Resource.Error("Network-Error: ${e.localizedMessage}", cached))
+            }
+        }
+        dao.getShareById(shareId).collect { share ->
+            if(share != null) emit(Resource.Success(share))
+            else emit(Resource.Error("Share nicht gefunden", null))
+        }
+    }
+
+    fun getSharesByExpenseId(token: String, expenseId: UUID, forceRefresh: Boolean = false): Flow<Resource<List<ExpenseShare>>> = flow {
+        val cached = dao.getSharesByExpense(expenseId).first()
+        emit(Resource.Loading(cached))
+        if(cached.isEmpty() || forceRefresh) {
+            try {
+                val response = api.shareGet("Bearer $token", expenseId, IDType.Expense)
+                if(response.isSuccessful) {
+                    println("Body: ${response.body()}")
+                    val remoteShare = response.body()?.shares ?: emptyList()
+                    remoteShare.forEach { dao.insertShare(it) }
+                }
+            } catch(e: Exception) {
+                emit(Resource.Error("Network Error: ${e.localizedMessage}", cached))
+            }
+        }
+        dao.getSharesByExpense(expenseId).collect { emit(Resource.Success(it)) }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/repository/Resource.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/repository/Resource.kt
@@ -0,0 +1,7 @@
+package de.miaurizius.shap_planner.repository
+
+sealed class Resource<T>(val data: T? = null, val message: String? = null) {
+    class Success<T>(data: T): Resource<T>(data)
+    class Loading<T>(data: T? = null): Resource<T>(data)
+    class Error<T>(message: String, data: T? = null): Resource<T>(data, message)
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/repository/UserRepository.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/repository/UserRepository.kt
@@ -0,0 +1,32 @@
+package de.miaurizius.shap_planner.repository
+
+import de.miaurizius.shap_planner.entities.User
+import de.miaurizius.shap_planner.entities.UserDao
+import de.miaurizius.shap_planner.network.APIService
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flow
+import java.util.UUID
+
+class UserRepository(
+    private val dao: UserDao,
+    private val api: APIService
+) {
+    fun getUser(token: String, userId: UUID, forceRefresh: Boolean = false): Flow<Resource<User>> = flow {
+        val cached = dao.getUserById(userId).first()
+        emit(Resource.Loading(cached))
+        if(cached == null || forceRefresh) {
+            try {
+                val response = api.userinfo("Bearer $token", userId)
+                if(response.isSuccessful) {
+                    println("Body: ${response.body()}")
+                    response.body()?.let { remoteUser -> dao.insertUser(remoteUser) }
+                }
+            } catch(e: Exception) {
+                emit(Resource.Error("Network-Error: ${e.localizedMessage}", cached))
+            }
+        }
+        dao.getUserById(userId).collect { user -> if(user != null) emit(Resource.Success(user)) else emit(
+            Resource.Error("User nicht gefunden", null)) }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/room/AppDatabase.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/room/AppDatabase.kt
@@ -4,12 +4,31 @@ import android.content.Context
 import androidx.room.Database
 import androidx.room.Room
 import androidx.room.RoomDatabase
+import androidx.room.TypeConverter
+import androidx.room.TypeConverters
 import de.miaurizius.shap_planner.entities.Account
 import de.miaurizius.shap_planner.entities.AccountDao
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseDao
+import de.miaurizius.shap_planner.entities.ExpenseShare
+import de.miaurizius.shap_planner.entities.ExpenseShareDao
+import de.miaurizius.shap_planner.entities.User
+import de.miaurizius.shap_planner.entities.UserDao

-@Database(entities = [Account::class], version = 2)
+class Converters {
+    @TypeConverter
+    fun fromList(list: List<String>?): String? = list?.joinToString(",")
+    @TypeConverter
+    fun toList(data: String?): List<String>? = data?.split(",")?.map { it.trim() }
+}
+
+@Database(entities = [Account::class, Expense::class, ExpenseShare::class, User::class], version = 6)
+@TypeConverters(Converters::class)
 abstract class AppDatabase : RoomDatabase() {
    abstract fun accountDao(): AccountDao
+    abstract fun expenseDao(): ExpenseDao
+    abstract fun expenseShareDao(): ExpenseShareDao
+    abstract fun userDao(): UserDao
    companion object {
        @Volatile
        private var INSTANCE: AppDatabase? = null
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/AppContent.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/AppContent.kt
@@ -0,0 +1,89 @@
+package de.miaurizius.shap_planner.ui
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.network.SessionState
+import de.miaurizius.shap_planner.ui.screens.AccountSelectionScreen
+import de.miaurizius.shap_planner.ui.screens.DashboardScreen
+import de.miaurizius.shap_planner.ui.screens.ExpenseCreationScreen
+import de.miaurizius.shap_planner.ui.screens.ExpenseDetailScreen
+import de.miaurizius.shap_planner.ui.screens.LoginScreen
+import de.miaurizius.shap_planner.viewmodels.ExpenseCreationViewModel
+import de.miaurizius.shap_planner.viewmodels.ExpenseDetailViewModel
+import de.miaurizius.shap_planner.viewmodels.MainViewModel
+
+@Composable
+fun AppContent(
+    // Login
+    accountList: List<Account>,
+    selectedAccount: Account?,
+    showLoginForNewAccount: Boolean,
+    onLogin: (String, String, String) -> Unit,
+
+    // Expenses
+    onExpenseClick: (Expense) -> Unit,
+
+    // Account
+    onSelectAccount: (Account) -> Unit,
+    onLogoutAccount: () -> Unit,
+    onAddAccountClick: () -> Unit,
+    onDeleteAccount: () -> Unit,
+
+    // Session
+    sessionState: SessionState,
+    onValidateSession: () -> Unit,
+    onSessionInvalid: () -> Unit,
+
+    //Important
+    viewModel: MainViewModel,
+    detailViewModel: ExpenseDetailViewModel,
+    creationViewModel: ExpenseCreationViewModel
+) {
+    var selectedExpense by remember { mutableStateOf<Expense?>(null) }
+    var showAddExpenseScreen by remember { mutableStateOf(false) }
+
+    when {
+        showAddExpenseScreen -> {
+            ExpenseCreationScreen(
+                account = selectedAccount!!,
+                viewModel = creationViewModel,
+                onBack = { showAddExpenseScreen = false },
+                onSaved = { showAddExpenseScreen = false },
+            )
+        }
+        selectedExpense != null -> {
+            ExpenseDetailScreen(
+                expense = selectedExpense!!,
+                account = selectedAccount!!,
+                viewModel = detailViewModel,
+                onBack = { selectedExpense = null }
+            )
+        }
+        showLoginForNewAccount -> LoginScreen(onLogin)
+        accountList.isEmpty() -> LoginScreen(onLogin)
+        selectedAccount != null -> DashboardScreen(
+            // Data and regarding Methods
+            account = selectedAccount,
+            onExpenseClick = { selectedExpense = it },
+
+            // Default Methods
+            mainViewModel = viewModel,
+            onBack = onLogoutAccount,
+            onDelete = onDeleteAccount,
+            sessionState = sessionState,
+            onValidate = onValidateSession,
+            onSessionInvalid = onSessionInvalid,
+            onAddExpenseClick = { showAddExpenseScreen = true },
+        )
+        else -> AccountSelectionScreen(
+            accounts = accountList,
+            onAccountClick = onSelectAccount,
+            onAddAccountClick = onAddAccountClick
+        )
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/screens/AccountSelectionScreen.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/screens/AccountSelectionScreen.kt
@@ -0,0 +1,188 @@
+package de.miaurizius.shap_planner.ui.screens
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Home
+import androidx.compose.material3.Button
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CenterAlignedTopAppBar
+import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import de.miaurizius.shap_planner.entities.Account
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun AccountSelectionScreen(
+    accounts: List<Account>,
+    onAccountClick: (Account) -> Unit,
+    onAddAccountClick: () -> Unit
+) {
+    Scaffold(
+        topBar = {
+            CenterAlignedTopAppBar(
+                title = { Text("ShAp-Planner", fontWeight = FontWeight.Black) }
+            )
+        },
+        bottomBar = {
+            Surface(
+                modifier = Modifier.fillMaxWidth(),
+                tonalElevation = 2.dp
+            ) {
+                Button(
+                    onClick = onAddAccountClick,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .padding(20.dp)
+                        .navigationBarsPadding()
+                        .height(56.dp),
+                    shape = MaterialTheme.shapes.medium
+                ) {
+                    Icon(Icons.Default.Add, contentDescription = null)
+                    Spacer(modifier = Modifier.width(8.dp))
+                    Text("Add New Account", style = MaterialTheme.typography.titleMedium)
+                }
+            }
+        }
+    ) { padding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(horizontal = 20.dp)
+        ) {
+            Spacer(modifier = Modifier.height(16.dp))
+
+            Text(
+                text = "Welcome back!",
+                style = MaterialTheme.typography.headlineLarge,
+                fontWeight = FontWeight.Bold
+            )
+            Text(
+                text = "Select an account to continue",
+                style = MaterialTheme.typography.bodyLarge,
+                color = MaterialTheme.colorScheme.secondary,
+                modifier = Modifier.padding(bottom = 16.dp)
+            )
+
+            LazyColumn(
+                modifier = Modifier.fillMaxSize(),
+                verticalArrangement = Arrangement.spacedBy(12.dp),
+                contentPadding = PaddingValues(bottom = 16.dp)
+            ) {
+                if (accounts.isEmpty()) {
+                    item {
+                        Box(
+                            modifier = Modifier.fillParentMaxHeight(0.6f).fillMaxWidth(),
+                            contentAlignment = Alignment.Center
+                        ) {
+                            Text(
+                                "No accounts yet.\nTap 'Add New Account' to start.",
+                                textAlign = TextAlign.Center,
+                                color = Color.Gray
+                            )
+                        }
+                    }
+                }
+
+                items(accounts) { account ->
+                    AccountItem(account = account, onClick = { onAccountClick(account) })
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun AccountItem(account: Account, onClick: () -> Unit) {
+    ElevatedCard(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clickable { onClick() },
+        shape = MaterialTheme.shapes.large,
+        colors = CardDefaults.elevatedCardColors(
+            containerColor = MaterialTheme.colorScheme.surface
+        )
+    ) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            // Stylized Avatar with Initial
+            Surface(
+                modifier = Modifier.size(52.dp),
+                shape = CircleShape,
+                color = MaterialTheme.colorScheme.primaryContainer
+            ) {
+                Box(contentAlignment = Alignment.Center) {
+                    Text(
+                        text = account.name.take(1).uppercase(),
+                        style = MaterialTheme.typography.titleLarge,
+                        fontWeight = FontWeight.Bold,
+                        color = MaterialTheme.colorScheme.onPrimaryContainer
+                    )
+                }
+            }
+
+            Spacer(modifier = Modifier.width(16.dp))
+
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = account.name,
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.Bold
+                )
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    Icon(
+                        Icons.Default.Home,
+                        contentDescription = null,
+                        modifier = Modifier.size(14.dp),
+                        tint = MaterialTheme.colorScheme.secondary
+                    )
+                    Spacer(modifier = Modifier.width(4.dp))
+                    Text(
+                        text = account.wgName,
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.secondary
+                    )
+                }
+            }
+
+            // Trailing Chevron
+            Icon(
+                Icons.AutoMirrored.Filled.KeyboardArrowRight,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.outline
+            )
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/screens/DashboardScreen.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/screens/DashboardScreen.kt
@@ -0,0 +1,217 @@
+package de.miaurizius.shap_planner.ui.screens
+
+import android.annotation.SuppressLint
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Refresh
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.network.SessionState
+import de.miaurizius.shap_planner.repository.Resource
+import de.miaurizius.shap_planner.viewmodels.MainViewModel
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun DashboardScreen(
+    account: Account,
+    onExpenseClick: (Expense) -> Unit,
+    onAddExpenseClick: () -> Unit,
+    mainViewModel: MainViewModel,
+    onBack: () -> Unit,
+    onDelete: () -> Unit,
+    sessionState: SessionState,
+    onValidate: () -> Unit,
+    onSessionInvalid: () -> Unit
+) {
+    val expenseResource by mainViewModel.expenseResource.collectAsState()
+
+    LaunchedEffect(Unit) { onValidate() }
+    LaunchedEffect(account) { mainViewModel.loadExpenses(account, forceRefresh = false) }
+
+    if (sessionState == SessionState.Invalid) {
+        LaunchedEffect(Unit) { onSessionInvalid() }
+        return
+    }
+
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = {
+                    Column {
+                        Text(account.wgName, style = MaterialTheme.typography.titleLarge)
+                        Text("Household", style = MaterialTheme.typography.labelSmall)
+                    }
+                },
+                actions = {
+                    IconButton(onClick = onBack) {
+                        Icon(Icons.Default.Refresh, "Switch")
+                    }
+                    IconButton(onClick = onDelete) {
+                        Icon(Icons.Default.Delete, "Delete", tint = MaterialTheme.colorScheme.error)
+                    }
+                }
+            )
+        },
+        floatingActionButton = {
+            androidx.compose.material3.FloatingActionButton(
+                onClick = onAddExpenseClick,
+                containerColor = MaterialTheme.colorScheme.primary,
+                contentColor = MaterialTheme.colorScheme.onPrimary
+            ) {
+                Icon(Icons.Default.Add, "Neu")
+            }
+        }
+    ) { paddingValues ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(paddingValues)
+                .background(MaterialTheme.colorScheme.surface)
+        ) {
+            Column(modifier = Modifier.padding(16.dp)) {
+                Text(
+                    text = "Hello, ${account.name}!",
+                    style = MaterialTheme.typography.headlineMedium,
+                    fontWeight = FontWeight.Bold
+                )
+
+                Spacer(modifier = Modifier.height(16.dp))
+
+                SummaryCard(expenses = expenseResource.data ?: emptyList())
+            }
+
+            Text(
+                text = "Latest expenses",
+                style = MaterialTheme.typography.titleMedium,
+                modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+                color = MaterialTheme.colorScheme.secondary
+            )
+
+            Box(modifier = Modifier.fillMaxSize()) {
+                if (expenseResource is Resource.Loading && expenseResource.data?.isEmpty() == true) {
+                    CircularProgressIndicator(modifier = Modifier.align(Alignment.Center))
+                }
+
+                LazyColumn(
+                    modifier = Modifier.fillMaxSize(),
+                    contentPadding = PaddingValues(16.dp),
+                    verticalArrangement = Arrangement.spacedBy(12.dp)
+                ) {
+                    items(expenseResource.data ?: emptyList()) { expense ->
+                        ExpenseItem(expense = expense, onClick = { onExpenseClick(expense) })
+                    }
+                }
+            }
+        }
+    }
+}
+
+@SuppressLint("DefaultLocale")
+@Composable
+fun SummaryCard(expenses: List<Expense>) {
+    val total = expenses.sumOf { it.amount } / 100.0
+    androidx.compose.material3.Card(
+        modifier = Modifier.fillMaxWidth(),
+        colors = androidx.compose.material3.CardDefaults.cardColors(
+            containerColor = MaterialTheme.colorScheme.primaryContainer
+        )
+    ) {
+        Column(modifier = Modifier.padding(20.dp)) {
+            Text("Total expenditure", style = MaterialTheme.typography.labelMedium)
+            Text(
+                text = String.format("%.2f €", total),
+                style = MaterialTheme.typography.displaySmall,
+                fontWeight = FontWeight.Black
+            )
+        }
+    }
+}
+
+@SuppressLint("DefaultLocale")
+@Composable
+fun ExpenseItem(expense: Expense, onClick: () -> Unit) {
+    androidx.compose.material3.ElevatedCard(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clickable { onClick() },
+        shape = MaterialTheme.shapes.medium,
+        colors = androidx.compose.material3.CardDefaults.elevatedCardColors(
+            containerColor = MaterialTheme.colorScheme.surface
+        )
+    ) {
+        Row(
+            modifier = Modifier
+                .padding(16.dp)
+                .fillMaxWidth(),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.SpaceBetween
+        ) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Surface(
+                    shape = androidx.compose.foundation.shape.CircleShape,
+                    color = MaterialTheme.colorScheme.primaryContainer,
+                    modifier = Modifier.size(40.dp)
+                ) {
+                    Box(contentAlignment = Alignment.Center) {
+                        Text(
+                            text = expense.title.take(1).uppercase(),
+                            style = MaterialTheme.typography.titleMedium,
+                            color = MaterialTheme.colorScheme.onPrimaryContainer
+                        )
+                    }
+                }
+
+                Spacer(modifier = Modifier.width(16.dp))
+
+                Column {
+                    Text(
+                        text = expense.title,
+                        style = MaterialTheme.typography.titleMedium,
+                        fontWeight = FontWeight.Bold
+                    )
+                }
+            }
+
+            Text(
+                text = String.format("%.2f €", expense.amount / 100.0),
+                style = MaterialTheme.typography.titleLarge,
+                fontWeight = FontWeight.ExtraBold,
+                color = MaterialTheme.colorScheme.primary
+            )
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/screens/ExpenseCreationScreen.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/screens/ExpenseCreationScreen.kt
@@ -0,0 +1,249 @@
+package de.miaurizius.shap_planner.ui.screens
+
+import android.annotation.SuppressLint
+import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Description
+import androidx.compose.material3.*
+import androidx.compose.runtime.*
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.viewmodels.ExpenseCreationViewModel
+
+@SuppressLint("DefaultLocale")
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ExpenseCreationScreen(
+    account: Account,
+    viewModel: ExpenseCreationViewModel,
+    onSaved: () -> Unit,
+    onBack: () -> Unit
+) {
+    var title by remember { mutableStateOf("") }
+    var description by remember { mutableStateOf("") }
+    var totalAmountStr by remember { mutableStateOf("") }
+    val attachmentUris = remember { mutableStateListOf<android.net.Uri>() }
+    val userShares = remember { mutableStateMapOf<java.util.UUID, String>() }
+    val users by viewModel.users.collectAsState()
+
+    // Real-time calculation logic
+    val totalCents = (totalAmountStr.replace(",", ".").toDoubleOrNull() ?: 0.0) * 100
+    val distributedCents = userShares.values.sumOf {
+        (it.replace(",", ".").toDoubleOrNull() ?: 0.0) * 100
+    }.toLong()
+
+    val diff = totalCents.toLong() - distributedCents
+    val isAmountMatched = totalCents > 0 && diff == 0L
+
+    // File Picker for multiple files (Images & PDFs)
+    val launcher = androidx.activity.compose.rememberLauncherForActivityResult(
+        contract = androidx.activity.result.contract.ActivityResultContracts.GetMultipleContents()
+    ) { uris ->
+        attachmentUris.addAll(uris)
+    }
+
+    LaunchedEffect(Unit) { viewModel.loadUsers() }
+
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = { Text("New Expense") },
+                navigationIcon = { IconButton(onClick = onBack) {
+                    Icon(Icons.AutoMirrored.Filled.ArrowBack, "Back")
+                } }
+            )
+        }
+    ) { padding ->
+        LazyColumn(
+            modifier = Modifier.fillMaxSize().padding(padding).padding(horizontal = 16.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp)
+        ) {
+            // Header Info
+            item {
+                Spacer(modifier = Modifier.height(8.dp))
+                ElevatedCard(modifier = Modifier.fillMaxWidth()) {
+                    Column(modifier = Modifier.padding(16.dp)) {
+                        OutlinedTextField(
+                            value = title,
+                            onValueChange = { title = it },
+                            label = { Text("Title *") },
+                            modifier = Modifier.fillMaxWidth()
+                        )
+                        Spacer(modifier = Modifier.height(12.dp))
+                        OutlinedTextField(
+                            value = totalAmountStr,
+                            onValueChange = { totalAmountStr = it },
+                            label = { Text("Total Amount (€) *") },
+                            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
+                            modifier = Modifier.fillMaxWidth()
+                        )
+                    }
+                }
+            }
+
+            // Optional Description & Multi-File Attachments
+            item {
+                Text("Additional Info", style = MaterialTheme.typography.titleMedium)
+                ElevatedCard(modifier = Modifier.fillMaxWidth()) {
+                    Column(modifier = Modifier.padding(16.dp)) {
+                        OutlinedTextField(
+                            value = description,
+                            onValueChange = { description = it },
+                            label = { Text("Description (Optional)") },
+                            modifier = Modifier.fillMaxWidth(),
+                            minLines = 2
+                        )
+                        Spacer(modifier = Modifier.height(16.dp))
+
+                        Text("Attachments (${attachmentUris.size})", style = MaterialTheme.typography.labelLarge)
+                        attachmentUris.forEach { uri ->
+                            Row(verticalAlignment = Alignment.CenterVertically) {
+                                Icon(Icons.Default.Description, "File", modifier = Modifier.size(20.dp))
+                                Text(" Document attached", modifier = Modifier.weight(1f), style = MaterialTheme.typography.bodySmall)
+                                IconButton(onClick = { attachmentUris.remove(uri) }) {
+                                    Icon(Icons.Default.Delete, "Remove", tint = Color.Red)
+                                }
+                            }
+                        }
+
+                        Button(onClick = { launcher.launch("*/*") }) {
+                            Text("Select Files (Images, PDF)")
+                        }
+                    }
+                }
+            }
+
+            // Split Details & Validation Message
+            item {
+                Column {
+                    Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween, verticalAlignment = Alignment.CenterVertically) {
+                        Text("Split Details *", style = MaterialTheme.typography.titleMedium)
+                        TextButton(onClick = {
+                            if (totalCents > 0) {
+                                val share = String.format("%.2f", (totalCents / users.size) / 100.0)
+                                users.forEach { userShares[it.id] = share }
+                            }
+                        }) { Text("Split Equally") }
+                    }
+
+                    // VALIDATION MESSAGE
+                    if (totalCents > 0) {
+                        val statusText = when {
+                            diff > 0 -> "Remaining: ${String.format("%.2f", diff / 100.0)} €"
+                            diff < 0 -> "Over-allocated: ${String.format("%.2f", Math.abs(diff) / 100.0)} €"
+                            else -> "Amount matched! ✓"
+                        }
+                        val statusColor = if (diff == 0L) Color(0xFF2E7D32) else MaterialTheme.colorScheme.error
+
+                        Surface(
+                            color = statusColor.copy(alpha = 0.1f),
+                            shape = MaterialTheme.shapes.small,
+                            modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp)
+                        ) {
+                            Text(
+                                text = statusText,
+                                color = statusColor,
+                                modifier = Modifier.padding(8.dp),
+                                style = MaterialTheme.typography.bodyMedium,
+                                fontWeight = FontWeight.Bold,
+                                textAlign = TextAlign.Center
+                            )
+                        }
+                    }
+                }
+            }
+
+            items(users) { user ->
+                UserShareInputItem(
+                    userName = user.name,
+                    amount = userShares[user.id] ?: "",
+                    onAmountChange = { userShares[user.id] = it }
+                )
+            }
+
+            // Save Actions
+            item {
+                Button(
+                    onClick = {
+                        viewModel.saveExpense(
+                            account = account,
+                            title = title,
+                            description = description,
+                            amountCents = totalCents.toInt(),
+                            shares = userShares.mapValues { (it.value.replace(",",".").toDoubleOrNull() ?: 0.0).toInt() * 100 }.filter { it.value > 0 },
+                            attachments = attachmentUris.map { it.toString() }
+                        )
+                        onSaved()
+                    },
+                    modifier = Modifier.fillMaxWidth().height(56.dp),
+                    enabled = title.isNotBlank() && isAmountMatched // STRICT VALIDATION
+                ) {
+                    Text("Save Expense")
+                }
+
+                if (totalAmountStr.isNotBlank() && !isAmountMatched) {
+                    Text(
+                        "Sum of shares must equal total amount to save.",
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.error,
+                        modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+                        textAlign = TextAlign.Center
+                    )
+                }
+
+                TextButton(onClick = onBack, modifier = Modifier.fillMaxWidth()) {
+                    Text("Cancel")
+                }
+                Spacer(modifier = Modifier.height(32.dp))
+            }
+        }
+    }
+}
+
+@Composable
+fun UserShareInputItem(userName: String, amount: String, onAmountChange: (String) -> Unit) {
+    Card(
+        modifier = Modifier.fillMaxWidth(),
+        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.3f))
+    ) {
+        Row(
+            modifier = Modifier.padding(12.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            Surface(
+                shape = androidx.compose.foundation.shape.CircleShape,
+                color = MaterialTheme.colorScheme.primaryContainer,
+                modifier = Modifier.size(32.dp)
+            ) {
+                Box(contentAlignment = Alignment.Center) {
+                    Text(userName.take(1).uppercase(), style = MaterialTheme.typography.bodySmall)
+                }
+            }
+            Spacer(modifier = Modifier.width(12.dp))
+            Text(userName, modifier = Modifier.weight(1f), style = MaterialTheme.typography.bodyLarge)
+
+            OutlinedTextField(
+                value = amount,
+                onValueChange = onAmountChange,
+                modifier = Modifier.width(100.dp),
+                placeholder = { Text("0.00") },
+                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
+                singleLine = true,
+                textStyle = MaterialTheme.typography.bodyMedium.copy(textAlign = TextAlign.End)
+            )
+            Spacer(modifier = Modifier.width(4.dp))
+            Text("€")
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/screens/ExpenseDetailScreen.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/screens/ExpenseDetailScreen.kt
@@ -0,0 +1,189 @@
+package de.miaurizius.shap_planner.ui.screens
+
+import android.annotation.SuppressLint
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.viewmodels.ExpenseDetailViewModel
+
+@SuppressLint("DefaultLocale")
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ExpenseDetailScreen(
+    expense: Expense,
+    account: Account,
+    viewModel: ExpenseDetailViewModel,
+    onBack: () -> Unit
+) {
+    val shares by viewModel.sharesWithUser.collectAsState()
+
+    LaunchedEffect(expense) {
+        viewModel.loadExpenseDetail(account, expense)
+    }
+
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = { Text("Expense Details") },
+                navigationIcon = {
+                    IconButton(onClick = onBack) {
+                        Icon(Icons.AutoMirrored.Filled.ArrowBack, contentDescription = "Back")
+                    }
+                }
+            )
+        }
+    ) { padding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(16.dp)
+        ) {
+            // Hero Section: Amount & Title
+            Column(
+                modifier = Modifier.fillMaxWidth().padding(bottom = 24.dp),
+                horizontalAlignment = Alignment.CenterHorizontally
+            ) {
+                Text(
+                    text = "Total Amount",
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.secondary
+                )
+                Text(
+                    text = String.format("%.2f €", expense.amount / 100.0),
+                    style = MaterialTheme.typography.displayMedium,
+                    fontWeight = FontWeight.Black,
+                    color = MaterialTheme.colorScheme.primary
+                )
+                Text(
+                    text = expense.title,
+                    style = MaterialTheme.typography.headlineSmall,
+                    fontWeight = FontWeight.Bold,
+                    textAlign = TextAlign.Center
+                )
+            }
+
+            // Description Card (only shown if not empty)
+            if (expense.description.isNotBlank()) {
+                androidx.compose.material3.ElevatedCard(
+                    modifier = Modifier.fillMaxWidth().padding(bottom = 24.dp),
+                    colors = androidx.compose.material3.CardDefaults.elevatedCardColors(
+                        containerColor = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f)
+                    )
+                ) {
+                    Column(modifier = Modifier.padding(16.dp)) {
+                        Text(
+                            text = "Description",
+                            style = MaterialTheme.typography.labelMedium,
+                            color = MaterialTheme.colorScheme.primary
+                        )
+                        Spacer(modifier = Modifier.height(4.dp))
+                        Text(text = expense.description, style = MaterialTheme.typography.bodyLarge)
+                    }
+                }
+            }
+
+            Text(
+                text = "Cost Distribution",
+                style = MaterialTheme.typography.titleMedium,
+                fontWeight = FontWeight.Bold,
+                modifier = Modifier.padding(bottom = 12.dp)
+            )
+
+            LazyColumn(
+                verticalArrangement = Arrangement.spacedBy(12.dp),
+                modifier = Modifier.fillMaxSize()
+            ) {
+                items(shares) { item ->
+                    ShareItem(
+                        name = item.user?.name ?: "Unknown User",
+                        amountCents = item.share.share_cents
+                    )
+                }
+            }
+        }
+    }
+}
+
+@SuppressLint("DefaultLocale")
+@Composable
+fun ShareItem(name: String, amountCents: Int) {
+    androidx.compose.material3.OutlinedCard(
+        modifier = Modifier.fillMaxWidth(),
+        shape = MaterialTheme.shapes.medium,
+        colors = androidx.compose.material3.CardDefaults.outlinedCardColors(
+            containerColor = MaterialTheme.colorScheme.surface
+        )
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(12.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            // User Avatar Circle
+            Surface(
+                shape = androidx.compose.foundation.shape.CircleShape,
+                color = MaterialTheme.colorScheme.secondaryContainer,
+                modifier = Modifier.size(36.dp)
+            ) {
+                Box(contentAlignment = Alignment.Center) {
+                    Text(
+                        text = name.take(1).uppercase(),
+                        style = MaterialTheme.typography.bodyMedium,
+                        fontWeight = FontWeight.Bold,
+                        color = MaterialTheme.colorScheme.onSecondaryContainer
+                    )
+                }
+            }
+
+            Spacer(modifier = Modifier.width(12.dp))
+
+            Text(
+                text = name,
+                style = MaterialTheme.typography.bodyLarge,
+                fontWeight = FontWeight.Medium,
+                modifier = Modifier.weight(1f)
+            )
+
+            Text(
+                text = String.format("%.2f €", amountCents / 100.0),
+                style = MaterialTheme.typography.bodyLarge,
+                fontWeight = FontWeight.Bold,
+                color = if (amountCents > 0) Color(0xFF2E7D32) else Color.Gray
+            )
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/ui/screens/LoginScreen.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/ui/screens/LoginScreen.kt
@@ -0,0 +1,176 @@
+package de.miaurizius.shap_planner.ui.screens
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Cloud
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.Person
+import androidx.compose.material.icons.filled.Visibility
+import androidx.compose.material.icons.filled.VisibilityOff
+import androidx.compose.material.icons.filled.VpnKey
+import androidx.compose.material3.Button
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.input.VisualTransformation
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun LoginScreen(
+    onLogin: (String, String, String) -> Unit,
+    onBack: (() -> Unit)? = null
+) {
+    if (onBack != null) {
+        BackHandler { onBack() }
+    }
+
+    var serverUrl by remember { mutableStateOf("") }
+    var username by remember { mutableStateOf("") }
+    var password by remember { mutableStateOf("") }
+    var passwordVisible by remember { mutableStateOf(false) }
+
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = { Text("Add Account", fontWeight = FontWeight.Bold) },
+                navigationIcon = {
+                    if (onBack != null) {
+                        IconButton(onClick = onBack) {
+                            Icon(Icons.AutoMirrored.Filled.ArrowBack, contentDescription = "Back")
+                        }
+                    }
+                }
+            )
+        }
+    ) { padding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(padding)
+                .padding(24.dp)
+                .verticalScroll(rememberScrollState()), // Scrollbar, falls die Tastatur den Platz wegnimmt
+            horizontalAlignment = Alignment.CenterHorizontally
+        ) {
+            // App Icon or Welcome Text
+            Icon(
+                imageVector = Icons.Default.Lock,
+                contentDescription = null,
+                modifier = Modifier.size(64.dp),
+                tint = MaterialTheme.colorScheme.primary
+            )
+
+            Text(
+                text = "Connect to Server",
+                style = MaterialTheme.typography.headlineMedium,
+                fontWeight = FontWeight.Bold,
+                modifier = Modifier.padding(top = 16.dp)
+            )
+
+            Text(
+                text = "Enter your credentials to link your account",
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.secondary,
+                textAlign = TextAlign.Center,
+                modifier = Modifier.padding(bottom = 32.dp)
+            )
+
+            // Server URL Field
+            OutlinedTextField(
+                value = serverUrl,
+                onValueChange = { serverUrl = it },
+                label = { Text("Server URL") },
+                placeholder = { Text("your-server.com") },
+                modifier = Modifier.fillMaxWidth(),
+                singleLine = true,
+                leadingIcon = { Icon(Icons.Default.Cloud, contentDescription = null) },
+                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Uri, imeAction = ImeAction.Next)
+            )
+
+            Spacer(modifier = Modifier.height(16.dp))
+
+            // Username Field
+            OutlinedTextField(
+                value = username,
+                onValueChange = { username = it },
+                label = { Text("Username") },
+                modifier = Modifier.fillMaxWidth(),
+                singleLine = true,
+                leadingIcon = { Icon(Icons.Default.Person, contentDescription = null) },
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next)
+            )
+
+            Spacer(modifier = Modifier.height(16.dp))
+
+            // Password Field
+            OutlinedTextField(
+                value = password,
+                onValueChange = { password = it },
+                label = { Text("Password") },
+                modifier = Modifier.fillMaxWidth(),
+                singleLine = true,
+                leadingIcon = { Icon(Icons.Default.VpnKey, contentDescription = null) },
+                visualTransformation = if (passwordVisible) VisualTransformation.None else PasswordVisualTransformation(),
+                keyboardOptions = KeyboardOptions(
+                    keyboardType = KeyboardType.Password,
+                    imeAction = ImeAction.Done
+                ),
+                trailingIcon = {
+                    val image = if (passwordVisible) Icons.Default.Visibility else Icons.Default.VisibilityOff
+                    IconButton(onClick = { passwordVisible = !passwordVisible }) {
+                        Icon(imageVector = image, contentDescription = "Toggle password visibility")
+                    }
+                }
+            )
+
+            Spacer(modifier = Modifier.height(32.dp))
+
+            // Login Button
+            Button(
+                onClick = { onLogin(serverUrl, username, password) },
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .height(56.dp),
+                enabled = serverUrl.isNotBlank() && username.isNotBlank() && password.isNotBlank(),
+                shape = MaterialTheme.shapes.medium
+            ) {
+                Text("Connect Account", style = MaterialTheme.typography.titleMedium)
+            }
+
+            if (onBack != null) {
+                TextButton(onClick = onBack, modifier = Modifier.padding(top = 8.dp)) {
+                    Text("Cancel", color = MaterialTheme.colorScheme.secondary)
+                }
+            }
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/viewmodels/ExpenseCreationViewModel.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/viewmodels/ExpenseCreationViewModel.kt
@@ -0,0 +1,66 @@
+package de.miaurizius.shap_planner.viewmodels
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import de.miaurizius.shap_planner.TokenStorage
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseDao
+import de.miaurizius.shap_planner.entities.ExpenseShare
+import de.miaurizius.shap_planner.entities.ExpenseShareDao
+import de.miaurizius.shap_planner.entities.User
+import de.miaurizius.shap_planner.entities.UserDao
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import java.util.UUID
+
+class ExpenseCreationViewModel(
+    private val userDao: UserDao,
+    private val expenseDao: ExpenseDao,
+    private val shareDao: ExpenseShareDao,
+    private val tokenStorage: TokenStorage
+) : ViewModel() {
+    private val _users = MutableStateFlow<List<User>>(emptyList())
+    val users: StateFlow<List<User>> = _users
+
+    fun loadUsers() {
+        viewModelScope.launch {
+            userDao.getAllUsers().collect { _users.value = it }
+        }
+    }
+
+    fun saveExpense(
+        account: Account,
+        title: String,
+        description: String,
+        amountCents: Int,
+        shares: Map<UUID, Int>,
+        attachments: List<String>
+    ) {
+//        viewModelScope.launch {
+//            val expenseId = UUID.randomUUID()
+//            val newExpense = Expense(
+//                id = expenseId,
+//                payer_id = account.id,
+//                amount = amountCents,
+//                title = title,
+//                description = description,
+//                attachments = if (attachments.isEmpty()) null else attachments,
+//                created_at = (System.currentTimeMillis() / 1000).toInt(),
+//                last_updated_at = 0
+//            )
+//
+//            expenseDao.insertExpense(newExpense)
+//
+//            shares.forEach { (userId, shareCents) ->
+//                shareDao.insertShare(
+//                    ExpenseShare(UUID.randomUUID(), expenseId, userId, shareCents)
+//                )
+//            }
+//
+//            // API POST Request
+//
+//        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/viewmodels/ExpenseDetailViewModel.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/viewmodels/ExpenseDetailViewModel.kt
@@ -0,0 +1,59 @@
+package de.miaurizius.shap_planner.viewmodels
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import de.miaurizius.shap_planner.TokenStorage
+import de.miaurizius.shap_planner.entities.Account
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseDao
+import de.miaurizius.shap_planner.entities.ExpenseShare
+import de.miaurizius.shap_planner.entities.ExpenseShareDao
+import de.miaurizius.shap_planner.entities.User
+import de.miaurizius.shap_planner.entities.UserDao
+import de.miaurizius.shap_planner.network.RetrofitProvider
+import de.miaurizius.shap_planner.repository.ExpenseShareRepository
+import de.miaurizius.shap_planner.repository.Resource
+import de.miaurizius.shap_planner.repository.UserRepository
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+
+data class ShareWithUser(
+    val share: ExpenseShare,
+    val user: User?
+)
+
+class ExpenseDetailViewModel(
+    private val expenseDao: ExpenseDao,
+    private val shareDao: ExpenseShareDao,
+    private val userDao: UserDao,
+    private val tokenStorage: TokenStorage
+) : ViewModel() {
+    private val _sharesWithUser = MutableStateFlow<List<ShareWithUser>>(emptyList())
+    val sharesWithUser: StateFlow<List<ShareWithUser>> = _sharesWithUser
+
+    fun loadExpenseDetail(account: Account, expense: Expense) {
+        viewModelScope.launch {
+            val api = RetrofitProvider.create(account.serverUrl)
+            val token = tokenStorage.getAccess(account.id.toString()) ?: ""
+
+            val shareRepo = ExpenseShareRepository(shareDao, api)
+            val userRepo = UserRepository(userDao, api)
+
+            shareRepo.getSharesByExpenseId(token, expense.id).collect { resource ->
+                val shares = resource.data ?: emptyList()
+                val combinedList = shares.map { share ->
+                    val cachedUser = userDao.getUserById(share.user_id).first()
+                    if (cachedUser == null) {
+                        val userResource = userRepo.getUser(token, share.user_id).first { it is Resource.Success || it is Resource.Error }
+                        ShareWithUser(share, userResource.data)
+                    } else {
+                        ShareWithUser(share, cachedUser)
+                    }
+                }
+                _sharesWithUser.value = combinedList
+            }
+        }
+    }
+}
--- a/app/src/main/java/de/miaurizius/shap_planner/viewmodels/LoginViewModel.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/viewmodels/LoginViewModel.kt
@@ -13,6 +13,7 @@ import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import java.util.Locale.getDefault
 import java.util.UUID

 class LoginViewModel(private val prefs: UserPreferences, private val appContext: Context) : ViewModel() {
@@ -28,7 +29,7 @@ class LoginViewModel(private val prefs: UserPreferences, private val appContext:

            try {
                val response = withContext(Dispatchers.IO) {
-                    api.login(LoginRequest(username, password))
+                    api.login(LoginRequest(username.lowercase(getDefault()).trim(), password))
                }

                if(response.isSuccessful) {
@@ -43,7 +44,7 @@ class LoginViewModel(private val prefs: UserPreferences, private val appContext:

                    val account = Account(
                        id = UUID.fromString(body.user.id),
-                        name = username,
+                        name = username.trim(),
                        wgName = body.wgName,
                        avatarUrl = null,
                        serverUrl = serverUrl,
--- a/app/src/main/java/de/miaurizius/shap_planner/viewmodels/MainViewModel.kt
+++ b/app/src/main/java/de/miaurizius/shap_planner/viewmodels/MainViewModel.kt
@@ -5,32 +5,108 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import de.miaurizius.shap_planner.TokenStorage
 import de.miaurizius.shap_planner.entities.Account
 import de.miaurizius.shap_planner.entities.AccountDao
+import de.miaurizius.shap_planner.entities.Expense
+import de.miaurizius.shap_planner.entities.ExpenseDao
+import de.miaurizius.shap_planner.network.RefreshRequest
+import de.miaurizius.shap_planner.network.RetrofitProvider
+import de.miaurizius.shap_planner.network.SessionState
+import de.miaurizius.shap_planner.repository.ExpenseRepository
+import de.miaurizius.shap_planner.repository.Resource
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import kotlin.collections.emptyList

-class MainViewModel(private val accountDao: AccountDao) : ViewModel() {
+class MainViewModel(
+    private val accountDao: AccountDao,
+    private val expenseDao: ExpenseDao,
+    private val tokenStorage: TokenStorage
+) : ViewModel() {

+    var selectedAccount by mutableStateOf<Account?>(null)
+        private set
    val accounts: StateFlow<List<Account>> = accountDao.getAllAccounts()
        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5000), emptyList())
+    var sessionState by mutableStateOf<SessionState>(SessionState.Loading)
+        private set
+
+    private val _expenseResource = MutableStateFlow<Resource<List<Expense>>>(Resource.Loading(emptyList()))
+    val expenseResource: StateFlow<Resource<List<Expense>>> = _expenseResource
+
+    fun loadExpenses(account: Account, forceRefresh: Boolean = false) {
+        viewModelScope.launch {
+            val api = RetrofitProvider.create(account.serverUrl)
+            val repo = ExpenseRepository(expenseDao, api)
+            val accessToken = tokenStorage.getAccess(account.id.toString()) ?: ""
+
+            repo.getExpenses(accessToken, forceRefresh).collect { result -> _expenseResource.value = result }
+        }
+    }
+
+    fun validateSession(account: Account) {
+        viewModelScope.launch {
+            sessionState = SessionState.Loading
+            val api = RetrofitProvider.create(account.serverUrl)
+
+            val accessToken = tokenStorage.getAccess(account.id.toString())
+            val refreshToken = tokenStorage.getRefresh(account.id.toString())
+
+            if(accessToken == null || refreshToken == null) {
+                sessionState = SessionState.Invalid
+                return@launch
+            }
+
+            val pingResponse = api.ping("Bearer $accessToken")
+
+            if(pingResponse.isSuccessful) {
+                sessionState = SessionState.Valid
+                return@launch
+            }
+
+            if(pingResponse.code() == 401) {
+                val refreshResponse = api.refresh(RefreshRequest(refreshToken))
+
+                if(refreshResponse.isSuccessful) {
+                    val newTokens = refreshResponse.body()!!
+
+                    tokenStorage.saveTokens(
+                        account.id.toString(),
+                        newTokens.access_token,
+                        newTokens.refresh_token
+                    )
+
+                    sessionState = SessionState.Valid
+
+                    return@launch
+                } else {
+                    sessionState = SessionState.Invalid
+                    return@launch
+                }
+            }
+            sessionState = SessionState.Error("Server error")
+        }
+    }

    fun addAccount(account: Account) {
        viewModelScope.launch {
            accountDao.insertAccount(account)
        }
    }
-
-    var selectedAccount by mutableStateOf<Account?>(null)
-        private set
-
+    fun deleteAccount(account: Account) {
+        viewModelScope.launch {
+            accountDao.deleteAccount(account)
+            tokenStorage.clearTokens(account.id.toString())
+            selectedAccount = null
+        }
+    }
    fun selectAccount(account: Account) {
        selectedAccount = account
    }
-
    fun logoutFromAccount() {
        selectedAccount = null
    }
--- a/app/src/main/res/xml/network_security_config.xml
+++ b/app/src/main/res/xml/network_security_config.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config>
+    <debug-overrides>
+        <trust-anchors>
+            <certificates src="user" />
+        </trust-anchors>
+    </debug-overrides>
+</network-security-config>
Author	SHA1	Message	Date
Maurice L.	463e1a013f	Improved UI and enhanced expense creation Updated the UI across all screens (Login, Dashboard, Account Selection, Expense Details, and Creation) with a more modern, card-based design and improved layouts. Expense creation now includes: - Real-time split validation to ensure shares match the total amount. - An "Equal Split" shortcut for quick allocation. - Support for optional descriptions and multiple file attachments. - Strict save validation. The `MainActivity` now supports edge-to-edge display, and the `AccountDao` includes a new query to fetch accounts by ID. Added `material-icons-extended` dependency for enhanced iconography.	2026-03-04 16:38:40 +01:00
Maurice L.	69e0344261	Implemented expense creation functionality. A new `ExpenseCreationScreen` and `ExpenseCreationViewModel` have been added to allow users to create new expenses. This includes fields for the title, amount, and a participant selection using filter chips. Key changes: - Added `ExpenseCreationViewModel` to handle user loading and persistent storage of expenses and shares. - Created `ExpenseCreationScreen` UI with validation for the "Save" button. - Updated `DashboardScreen` to include a Floating Action Button (FAB) for navigating to the expense creation flow. - Added `expenseCreate` API endpoint and related data types (`ExpenseCreationRequest`, `ExpenseCreationResponse`). - Integrated `ExpenseCreationViewModel` into `MainActivity` and `AppContent`.	2026-03-04 14:55:31 +01:00
Maurice L.	25d1038c9d	Updated UI text to English and improved currency formatting The UI strings in `ExpenseDetailScreen`, `DashboardScreen`, and `AccountSelectionScreen` have been translated from German to English. Additionally, currency display logic has been updated to use `String.format("%.2f€", ...)` for consistent two-decimal formatting across the `ExpenseDetailScreen` and `DashboardScreen`.	2026-03-04 14:22:21 +01:00
Maurice L.	ea6349c85c	Added Expense Detail screen and functionality The new `ExpenseDetailScreen` displays expense information, including title, amount, and a breakdown of cost shares among users. Key changes: - Created `ExpenseDetailViewModel` to manage loading and combining expense shares with user information. - Added `ExpenseDetailScreen` UI with a list of shares and a back navigation option. - Updated `MainActivity` and `AppContent` to handle navigation to the expense detail view. - Extended `ExpenseShareDao` and `ExpenseShareRepository` to support fetching shares by expense ID. - Updated `APIService` and `UserRepository` to simplify user information retrieval and support querying shares by different ID types. - Added `@OptIn(ExperimentalMaterial3Api::class)` to several UI components to support Material 3 features.	2026-03-04 14:16:45 +01:00
Maurice L.	4104930ea5	Added UserRepository and ExpenseShareRepository Implemented `UserRepository` and `ExpenseShareRepository` to handle data fetching with a caching strategy (local DAO + remote API). Specific changes include: - Added `getUserById` to `UserDao` and updated `getShareById` in `ExpenseShareDao` to support nullable returns. - Updated `APIService` and `ComDataTypes` to include endpoints and data models for User info, Expense Shares, and pluralized Expense responses. - Refactored `ExpenseRepository` to use the updated API naming conventions and removed debug print statements.	2026-03-04 12:28:12 +01:00
Maurice L.	3d789c0352	Implemented a repository-based data layer for expenses and updated Room entities. The `ExpenseRepository` was introduced to handle data fetching with a caching strategy, utilizing a new `Resource` sealed class to represent Loading, Success, and Error states. Key changes include: - Added `ExpenseRepository` to manage data flow between the local database and remote API. - Updated `MainViewModel` to use the repository and expose expenses via a `StateFlow<Resource<List<Expense>>>`. - Enhanced Room entities (`Expense`, `ExpenseShare`, `User`) with `@PrimaryKey` annotations and added a `Converters` class to handle `List<String>` types. - Expanded `AppDatabase` to include DAOs for `Expense`, `ExpenseShare`, and `User`. - Updated `DashboardScreen` to reactively display loading indicators, error messages, and cached/remote expense data.	2026-03-04 11:56:57 +01:00
Maurice L.	37d8e8cc74	Refined network configuration and login UI The login screen now labels the server input as "Server-Domain", and the network provider has been updated to automatically prepend the HTTPS protocol. The database version has been incremented, and a network security configuration has been added to allow user certificates for debugging. Additionally, the encrypted shared preferences storage name was updated.	2026-03-03 16:30:21 +01:00
Maurice L.	f3f83b7ca9	Implemented expense tracking and data fetching The `Expense` entity and its associated API endpoints have been updated, and a new `ExpenseShare` entity with a corresponding DAO has been added. The `MainViewModel` now includes logic to fetch expenses from the server upon successful session validation. The `DashboardScreen` has been updated to display a list of expenses using a `LazyColumn` and a new `ExpenseItem` component. Additionally, the `APIService` has been expanded to include CRUD operations for expenses and user information.	2026-03-01 16:55:09 +01:00
Maurice L.	552f604200	Updated RefreshResponse field names and token handling The `RefreshResponse` data class has been updated to use `access_token` and `refresh_token` to match the API response. Consequently, `MainViewModel` now uses these updated field names when saving new tokens to storage. Debug print statements for access and refresh tokens have also been removed.	2026-02-27 22:21:13 +01:00
Maurice L.	f01357987c	Cleaned up AndroidManifest.xml The manifest has been simplified by removing unused namespace declarations and redundant activity labels. Extraneous whitespace and empty lines were also removed for better readability.	2026-02-27 20:35:32 +01:00
Maurice L.	b4229c29c4	Cleaned up unused imports Removed several unused Compose and utility imports from `MainActivity.kt`, `LoginViewModel.kt`, and `APIService.kt` to improve code cleanliness.	2026-02-27 20:06:49 +01:00
Maurice L.	d05d93a0d7	Refactored UI components and extracted screens into separate files. The UI logic from `MainActivity.kt` has been moved into a new `AppContent` composable, and individual screens (`LoginScreen`, `DashboardScreen`, `AccountSelectionScreen`) have been extracted to their own files within the `ui.screens` package. Additional changes: - Updated `MainActivity` to use the new `AppContent` structure and handled back navigation for new account logins. - Fixed a field name mismatch in `RefreshRequest` within `APIService.kt`, changing `refreshToken` to `refresh_token`. - Minor formatting update in `README.md`.	2026-02-27 20:04:05 +01:00
Maurice L.	37e125945b	Added a README.md file	2026-02-27 19:34:07 +01:00
Maurice L.	463e9b6258	Updated .gitignore The `.gitignore` file has been reorganized and expanded to include standard exclusions for build artifacts, Kotlin/Java project files, Android Studio metadata, keys/secrets, and OS-generated files.	2026-02-27 19:26:25 +01:00
Maurice L.	e99e951232	Updated Login and Git configuration The `LoginViewModel` now trims whitespace from usernames during the login request and account creation process. The `.gitignore` file has been updated to exclude `.jks` files and the `/app/release` directory.	2026-02-27 19:23:04 +01:00
Maurice L.	ca1ad57f7e	Implemented session validation and token refreshing Added a `SessionState` sealed class to track the connection status and integrated it into the `DashboardScreen`. The dashboard now triggers a session validation on launch, showing a loading indicator during the check. The `MainViewModel` has been updated with a `validateSession` function that: - Pings the server using the stored access token. - Attempts to refresh the token if a 401 Unauthorized response is received. - Updates the `TokenStorage` with new tokens upon successful refresh. - Redirects to logout if both tokens are invalid. Additionally, the `APIService` was expanded with `ping` and `refresh` endpoints, and the `AppDatabase` version was incremented.	2026-02-27 19:04:28 +01:00
Maurice L.	8ad212ee76	Integrated TokenStorage into MainViewModel MainViewModel now accepts a `TokenStorage` instance. When an account is deleted, its associated tokens are now cleared from storage. MainActivity has been updated to initialize and provide the `TokenStorage` to the view model.	2026-02-27 18:33:34 +01:00
Maurice L.	dc9f4121e0	Added account deletion and improved login case-insensitivity The Dashboard now includes a "Löschen" (Delete) button that allows users to remove the currently selected account via the `MainViewModel`. The login process has been updated to convert usernames to lowercase before authentication to ensure consistency. Additionally, spacing adjustments were made to the Dashboard UI layout.	2026-02-27 18:28:17 +01:00
Maurice L.	d94b3f74de	Improved account management and navigation The app now supports adding a new account without logging out of the current session. A `BackHandler` has been implemented in the `LoginScreen` and `DashboardScreen` to improve navigation flow, and the `LoginScreen` now accepts an optional `onBack` callback.	2026-02-27 18:15:18 +01:00