Finally fix the double navigation issue event

Dialogs now survive screen rotation
Improve empty screens placeholders

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/screen/DueTodayTasksScreen.kt

@@ -1,10 +1,16 @@
 package com.wismna.geoffroy.donext.presentation.screen
 
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarToday
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
@@ -26,7 +32,14 @@ fun DueTodayTasksScreen(
             modifier = modifier.fillMaxSize(),
             contentAlignment = Alignment.Center
         ) {
-            Text("Nothing due today !")
+            Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                Icon(
+                    Icons.Default.CalendarToday,
+                    contentDescription = "Due today background icon",
+                    modifier = Modifier.size(60.dp),
+                    tint = MaterialTheme.colorScheme.secondary)
+                Text("Nothing due today !", color = MaterialTheme.colorScheme.secondary)
+            }
         }
     } else {
         LazyColumn(

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/screen/MainScreen.kt

@@ -206,7 +206,6 @@ fun AppContent(
                     navController.navigate(event.route)
                 }
                 is UiEvent.NavigateBack -> navController.popBackStack()
-                is UiEvent.EditTask -> { viewModel.showTaskSheet = true }
                 is UiEvent.ShowUndoSnackbar -> {
                     val result = snackbarHostState.showSnackbar(
                         message = event.message,
@@ -221,6 +220,15 @@ fun AppContent(
             }
         }
     }
+    LaunchedEffect(Unit) {
+        viewModel.uiEventBus.stickyEvents.collect { event ->
+            when (event) {
+                is UiEvent.EditTask -> { viewModel.showTaskSheet = true }
+                else -> Unit
+            }
+        }
+    }
+
     Scaffold(
         modifier = modifier.background(MaterialTheme.colorScheme.primaryContainer),
         containerColor = Color.Transparent,

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/screen/RecycleBinScreen.kt

@@ -2,12 +2,15 @@ package com.wismna.geoffroy.donext.presentation.screen
 
 import android.widget.Toast
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.DeleteOutline
 import androidx.compose.material.icons.filled.DeleteSweep
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ButtonDefaults
@@ -19,9 +22,6 @@ import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 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.draw.alpha
@@ -29,6 +29,7 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.wismna.geoffroy.donext.presentation.viewmodel.RecycleBinViewModel
 
 @Composable
@@ -37,6 +38,7 @@ fun RecycleBinScreen(
     viewModel: RecycleBinViewModel = hiltViewModel(),
 ) {
     val tasks = viewModel.deletedTasks
+    val taskToDelete by viewModel.taskToDeleteFlow.collectAsStateWithLifecycle()
 
     if (tasks.isEmpty()) {
         // Placeholder when recycle bin is empty
@@ -44,7 +46,15 @@ fun RecycleBinScreen(
             modifier = modifier.fillMaxSize(),
             contentAlignment = Alignment.Center
         ) {
-            Text("Recycle Bin is empty")
+            Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                Icon(
+                    Icons.Default.DeleteOutline,
+                    contentDescription = "Recycle bin background icon",
+                    modifier = Modifier.size(60.dp),
+                    tint = MaterialTheme.colorScheme.secondary
+                )
+                Text("Recycle Bin is empty", color = MaterialTheme.colorScheme.secondary)
+            }
         }
         return
     }
@@ -52,7 +62,7 @@ fun RecycleBinScreen(
     val grouped = tasks.groupBy { it.listName }
     val context = LocalContext.current
 
-    if (viewModel.taskToDelete != null) {
+    if (taskToDelete != null) {
         AlertDialog(
             onDismissRequest = { viewModel.onCancelDelete() },
             title = { Text("Delete task") },
@@ -114,10 +124,10 @@ fun RecycleBinScreen(
 @Composable
 fun EmptyRecycleBinAction(viewModel: RecycleBinViewModel = hiltViewModel()) {
     val isEmpty = viewModel.deletedTasks.isEmpty()
-    var showConfirmDialog by remember { mutableStateOf(false) }
+    val emptyRecycleBin by viewModel.emptyRecycleBinFlow.collectAsStateWithLifecycle()
 
     IconButton(
-        onClick = { showConfirmDialog = true },
+        onClick = { viewModel.onEmptyRecycleBinRequest() },
         enabled = !isEmpty) {
         Icon(
             Icons.Default.DeleteSweep,
@@ -127,9 +137,9 @@ fun EmptyRecycleBinAction(viewModel: RecycleBinViewModel = hiltViewModel()) {
         )
     }
 
-    if (showConfirmDialog) {
+    if (emptyRecycleBin) {
         AlertDialog(
-            onDismissRequest = { showConfirmDialog = false },
+            onDismissRequest = { viewModel.onCancelEmptyRecycleBinRequest() },
             title = { Text("Empty Recycle Bin") },
             text = {
                 Text("Are you sure you want to permanently delete all tasks in the recycle bin? This cannot be undone.")
@@ -138,7 +148,6 @@ fun EmptyRecycleBinAction(viewModel: RecycleBinViewModel = hiltViewModel()) {
                 TextButton(
                     onClick = {
                         viewModel.emptyRecycleBin()
-                        showConfirmDialog = false
                     },
                     colors = ButtonDefaults.textButtonColors(
                         contentColor = MaterialTheme.colorScheme.error
@@ -148,7 +157,7 @@ fun EmptyRecycleBinAction(viewModel: RecycleBinViewModel = hiltViewModel()) {
                 }
             },
             dismissButton = {
-                TextButton(onClick = { showConfirmDialog = false }) {
+                TextButton(onClick = { viewModel.onCancelEmptyRecycleBinRequest() }) {
                     Text("Cancel")
                 }
             }

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/ui/events/UiEventBus.kt

@@ -1,5 +1,6 @@
 package com.wismna.geoffroy.donext.presentation.ui.events
 
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
 import javax.inject.Inject
@@ -7,10 +8,24 @@ import javax.inject.Singleton
 
 @Singleton
 class UiEventBus @Inject constructor() {
-    private val _events = MutableSharedFlow<UiEvent>(replay = 1)
+    // Non-replayable (e.g. navigation, snackbar)
+    private val _events = MutableSharedFlow<UiEvent>(replay = 0, extraBufferCapacity = 1)
     val events = _events.asSharedFlow()
 
+    // Replayable (e.g. edit/create task)
+    private val _stickyEvents = MutableSharedFlow<UiEvent>(replay = 1, extraBufferCapacity = 1)
+    val stickyEvents = _stickyEvents.asSharedFlow()
+
     suspend fun send(event: UiEvent) {
-        _events.emit(event)
+        when (event) {
+            is UiEvent.EditTask,
+            is UiEvent.CreateNewTask -> _stickyEvents.emit(event)
+            else -> _events.emit(event)
+        }
+    }
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    fun clearSticky() {
+        _stickyEvents.resetReplayCache()
     }
 }

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/viewmodel/MainViewModel.kt

@@ -71,6 +71,7 @@ class MainViewModel @Inject constructor(
         showTaskSheet = false
         viewModelScope.launch {
             uiEventBus.send(UiEvent.CloseTask)
+            uiEventBus.clearSticky()
         }
     }
 

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/viewmodel/RecycleBinViewModel.kt

@@ -30,11 +30,15 @@ class RecycleBinViewModel @Inject constructor(
     private val savedStateHandle: SavedStateHandle
 ) : ViewModel() {
 
+    companion object {
+        private const val TASK_TO_DELETE = "taskToDeleteId"
+        private const val EMPTY_RECYCLE_BIN = "emptyRecycleBin"
+    }
     var deletedTasks by mutableStateOf<List<TaskWithListName>>(emptyList())
         private set
 
-    var taskToDelete by mutableStateOf(savedStateHandle.get<Long>("taskToDelete"))
+    val taskToDeleteFlow = savedStateHandle.getStateFlow<Long?>(TASK_TO_DELETE, null)
-        private set
+    val emptyRecycleBinFlow = savedStateHandle.getStateFlow<Boolean>(EMPTY_RECYCLE_BIN, false)
 
     init {
         loadDeletedTasks()
@@ -70,29 +74,36 @@ class RecycleBinViewModel @Inject constructor(
             )
         }
     }
-    fun onTaskDeleteRequest(taskId: Long) {
+
-        taskToDelete = taskId
+    fun onEmptyRecycleBinRequest() {
-        savedStateHandle["taskToDelete"] = taskId
+        savedStateHandle[EMPTY_RECYCLE_BIN] = true
     }
 
-    fun onConfirmDelete() {
+    fun onCancelEmptyRecycleBinRequest() {
-        taskToDelete?.let {
+        savedStateHandle[EMPTY_RECYCLE_BIN] = false
-            viewModelScope.launch {
-                permanentlyDeleteTaskUseCase(it)
-            }
-        }
-        taskToDelete = null
-        savedStateHandle["taskToDelete"] = null
-    }
-
-    fun onCancelDelete() {
-        taskToDelete = null
-        savedStateHandle["taskToDelete"] = null
     }
 
     fun emptyRecycleBin() {
         viewModelScope.launch {
             emptyRecycleBinUseCase()
+            savedStateHandle[EMPTY_RECYCLE_BIN] = false
         }
     }
+
+    fun onTaskDeleteRequest(taskId: Long) {
+        savedStateHandle[TASK_TO_DELETE] = taskId
+    }
+
+    fun onConfirmDelete() {
+        taskToDeleteFlow.value?.let {
+            viewModelScope.launch {
+                permanentlyDeleteTaskUseCase(it)
+            }
+        }
+        savedStateHandle[TASK_TO_DELETE] = null
+    }
+
+    fun onCancelDelete() {
+        savedStateHandle[TASK_TO_DELETE] = null
+    }
 }

donextv2/src/main/java/com/wismna/geoffroy/donext/presentation/viewmodel/TaskViewModel.kt

@@ -37,13 +37,14 @@ class TaskViewModel @Inject constructor(
         private set
     var isDeleted by mutableStateOf(false)
         private set
-
+    var taskListId by mutableStateOf<Long?>(null)
-    private var editingTaskId: Long? = null
+        private set
-    private var taskListId: Long? = null
+    var editingTaskId by mutableStateOf<Long?>(null)
+        private set
 
     init {
         viewModelScope.launch {
-            uiEventBus.events.collect { event ->
+            uiEventBus.stickyEvents.collect { event ->
                 when (event) {
                     is UiEvent.CreateNewTask -> startNewTask(event.taskListId)
                     is UiEvent.EditTask -> startEditTask(event.task)