Create UI events

Create a event bus singleton
Handle navigation through events
Handle task creation and edition through events

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

@@ -50,10 +50,11 @@ import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.rememberNavController
 import androidx.navigation.navArgument
 import com.wismna.geoffroy.donext.domain.model.AppDestination
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEvent
 import com.wismna.geoffroy.donext.presentation.viewmodel.MainViewModel
 import com.wismna.geoffroy.donext.presentation.viewmodel.TaskListViewModel
-import com.wismna.geoffroy.donext.presentation.viewmodel.TaskViewModel
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 
 @Composable
@@ -63,8 +64,6 @@ fun MainScreen(
     val navController = rememberNavController()
     val drawerState = rememberDrawerState(DrawerValue.Closed)
     val scope = rememberCoroutineScope()
-    // TODO: find a way to do this better
-    val taskViewModel: TaskViewModel = hiltViewModel()
 
     if (viewModel.isLoading) {
         Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
@@ -74,7 +73,7 @@ fun MainScreen(
     }
 
     if (viewModel.showTaskSheet) {
-        TaskBottomSheet(taskViewModel) { viewModel.showTaskSheet = false }
+        TaskBottomSheet { viewModel.onDismissTaskSheet() }
     }
     if (viewModel.showAddListSheet) {
         AddListBottomSheet { viewModel.showAddListSheet = false }
@@ -85,21 +84,11 @@ fun MainScreen(
 
     ModalNavigationDrawer(
         drawerContent = {
-            MenuScreen (
+            MenuScreen (currentDestination = viewModel.currentDestination)
-                currentDestination = viewModel.currentDestination,
-                onNavigate = { route ->
-                    scope.launch {
-                        drawerState.close()
-                        navController.navigate(route) {
-                            restoreState = true
-                        }
-                    }
-                }
-            )
         },
         drawerState = drawerState
     ) {
-        AppContent(viewModel = viewModel, taskViewModel = taskViewModel, navController = navController, scope = scope, drawerState = drawerState)
+        AppContent(viewModel = viewModel, navController = navController, scope = scope, drawerState = drawerState)
     }
 }
 
@@ -107,11 +96,22 @@ fun MainScreen(
 fun AppContent(
     modifier : Modifier = Modifier,
     viewModel: MainViewModel,
-    taskViewModel: TaskViewModel,
     navController: NavHostController,
     scope: CoroutineScope,
     drawerState: DrawerState
 ) {
+    LaunchedEffect(Unit) {
+        viewModel.uiEventBus.events.collectLatest { event ->
+            when (event) {
+                is UiEvent.Navigate -> {
+                    drawerState.close()
+                    navController.navigate(event.route)
+                }
+                is UiEvent.NavigateBack -> navController.popBackStack()
+                else -> {}
+            }
+        }
+    }
     Scaffold(
         modifier = modifier.background(MaterialTheme.colorScheme.primaryContainer),
         containerColor = Color.Transparent,
@@ -126,7 +126,7 @@ fun AppContent(
                 navigationIcon = {
                     CompositionLocalProvider(LocalContentColor provides MaterialTheme.colorScheme.onPrimaryContainer) {
                         if (viewModel.currentDestination.showBackButton) {
-                            IconButton(onClick = { navController.popBackStack() }) {
+                            IconButton(onClick = { viewModel.navigateBack() }) {
                                 Icon(Icons.AutoMirrored.Default.ArrowBack, contentDescription = "Back")
                             }
                         } else {
@@ -158,10 +158,7 @@ fun AppContent(
             when (val dest = viewModel.currentDestination) {
                 is AppDestination.TaskList -> {
                     ExtendedFloatingActionButton(
-                        onClick = {
+                        onClick = { viewModel.onNewTaskButtonClicked(dest.taskListId) },
-                            taskViewModel.startNewTask(dest.taskListId)
-                            viewModel.showTaskSheet = true
-                        },
                         icon = { Icon(Icons.Filled.Add, "Create a task.") },
                         text = { Text("Create a task") },
                     )
@@ -205,17 +202,14 @@ fun AppContent(
                     }
                     LaunchedEffect(listExists) {
                         if (!viewModel.doesListExist(taskListId)) {
-                            navController.popBackStack()
+                            viewModel.navigateBack()
                         }
                     }
 
                     val taskListViewModel: TaskListViewModel = hiltViewModel(navBackStackEntry)
                     TaskListScreen(
                         viewModel = taskListViewModel,
-                        onTaskClick = { task ->
+                        onTaskClick = { task -> viewModel.onTaskClicked(task) }
-                            taskViewModel.startEditTask(task)
-                            viewModel.showTaskSheet = true
-                        }
                     )
                 }
 
@@ -228,19 +222,13 @@ fun AppContent(
                 composable(AppDestination.DueTodayList.route) {
                     DueTodayTasksScreen (
                         modifier = Modifier,
-                        onTaskClick = { task ->
+                        onTaskClick = { task -> viewModel.onTaskClicked(task) }
-                            taskViewModel.startEditTask(task)
-                            viewModel.showTaskSheet = true
-                        }
                     )
                 }
                 composable(AppDestination.RecycleBin.route) {
                     RecycleBinScreen(
                         modifier = Modifier,
-                        onTaskClick = { task ->
+                        onTaskClick = { task -> viewModel.onTaskClicked(task) }
-                            taskViewModel.startEditTask(task)
-                            viewModel.showTaskSheet = true
-                        }
                     )
                 }
             }

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

@@ -31,7 +31,6 @@ import com.wismna.geoffroy.donext.presentation.viewmodel.MenuViewModel
 fun MenuScreen(
     viewModel: MenuViewModel = hiltViewModel(),
     currentDestination: AppDestination,
-    onNavigate: (String) -> Unit
 ) {
     ModalDrawerSheet(
         drawerContainerColor = MaterialTheme.colorScheme.surfaceVariant,
@@ -58,7 +57,7 @@ fun MenuScreen(
                     },
                     icon = { Icon(Icons.Default.Today, contentDescription = "Due Today") },
                     selected = currentDestination is AppDestination.DueTodayList,
-                    onClick = { onNavigate(AppDestination.DueTodayList.route) },
+                    onClick = { viewModel.navigateTo(AppDestination.DueTodayList.route) },
                     modifier = Modifier.padding(NavigationDrawerItemDefaults.ItemPadding)
                 )
                 HorizontalDivider()
@@ -74,7 +73,7 @@ fun MenuScreen(
                         icon = { Icon(Icons.Default.LineWeight, contentDescription = list.name) },
                         selected = currentDestination is AppDestination.TaskList &&
                                 currentDestination.taskListId == list.id,
-                        onClick = { onNavigate("taskList/${list.id}") },
+                        onClick = { viewModel.navigateTo("taskList/${list.id}") },
                         badge = {
                             if (list.overdueCount > 0) {
                                 Badge { Text(list.overdueCount.toString()) }
@@ -91,14 +90,14 @@ fun MenuScreen(
                     label = { Text("Recycle Bin") },
                     icon = { Icon(Icons.Default.Delete, contentDescription = "Recycle Bin") },
                     selected = currentDestination is AppDestination.RecycleBin,
-                    onClick = { onNavigate(AppDestination.RecycleBin.route) },
+                    onClick = { viewModel.navigateTo(AppDestination.RecycleBin.route) },
                     modifier = Modifier.padding(NavigationDrawerItemDefaults.ItemPadding)
                 )
                 NavigationDrawerItem(
                     label = { Text("Edit Lists") },
                     icon = { Icon(Icons.Default.EditNote, contentDescription = "Edit Lists") },
                     selected = currentDestination is AppDestination.ManageLists,
-                    onClick = { onNavigate(AppDestination.ManageLists.route) },
+                    onClick = { viewModel.navigateTo(AppDestination.ManageLists.route) },
                     modifier = Modifier.padding(NavigationDrawerItemDefaults.ItemPadding)
                 )
             }

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

@@ -40,6 +40,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.unit.dp
+import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.wismna.geoffroy.donext.domain.extension.toLocalDate
 import com.wismna.geoffroy.donext.domain.model.Priority
 import com.wismna.geoffroy.donext.presentation.viewmodel.TaskViewModel
@@ -53,7 +54,7 @@ import java.time.format.FormatStyle
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun TaskBottomSheet(
-    viewModel: TaskViewModel,
+    viewModel: TaskViewModel = hiltViewModel(),
     onDismiss: () -> Unit
 ) {
     val titleFocusRequester = remember { FocusRequester() }

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

@@ -0,0 +1,13 @@
+package com.wismna.geoffroy.donext.presentation.ui.events
+
+import com.wismna.geoffroy.donext.domain.model.Task
+
+sealed class UiEvent {
+    data class Navigate(val route: String) : UiEvent()
+    data object NavigateBack : UiEvent()
+    data class ShowSnackbar(val message: String) : UiEvent()
+
+    data class EditTask(val task: Task) : UiEvent()
+    data class CreateNewTask(val taskListId: Long) : UiEvent()
+    data object CloseTask : UiEvent()
+}

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

@@ -7,15 +7,20 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavBackStackEntry
 import com.wismna.geoffroy.donext.domain.model.AppDestination
+import com.wismna.geoffroy.donext.domain.model.Task
 import com.wismna.geoffroy.donext.domain.usecase.GetTaskListsUseCase
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEvent
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEventBus
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class MainViewModel @Inject constructor(
-    getTaskListsUseCase: GetTaskListsUseCase
+    getTaskListsUseCase: GetTaskListsUseCase,
+    val uiEventBus: UiEventBus
 ) : ViewModel() {
 
     var isLoading by mutableStateOf(true)
@@ -50,6 +55,33 @@ class MainViewModel @Inject constructor(
             .launchIn(viewModelScope)
     }
 
+    fun navigateBack() {
+        viewModelScope.launch {
+            uiEventBus.send(UiEvent.NavigateBack)
+        }
+    }
+
+    fun onNewTaskButtonClicked(taskLisId: Long) {
+        showTaskSheet = true
+        viewModelScope.launch {
+            uiEventBus.send(UiEvent.CreateNewTask(taskLisId))
+        }
+    }
+
+    fun onTaskClicked(task: Task) {
+        showTaskSheet = true
+        viewModelScope.launch {
+            uiEventBus.send(UiEvent.EditTask(task))
+        }
+    }
+
+    fun onDismissTaskSheet() {
+        showTaskSheet = false
+        viewModelScope.launch {
+            uiEventBus.send(UiEvent.CloseTask)
+        }
+    }
+
     fun setCurrentDestination(navBackStackEntry: NavBackStackEntry?) {
         val route = navBackStackEntry?.destination?.route
         val taskListId = navBackStackEntry?.arguments?.getLong("taskListId")

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

@@ -9,17 +9,20 @@ import androidx.lifecycle.viewModelScope
 import com.wismna.geoffroy.donext.domain.model.TaskListWithOverdue
 import com.wismna.geoffroy.donext.domain.usecase.GetDueTodayTasksUseCase
 import com.wismna.geoffroy.donext.domain.usecase.GetTaskListsWithOverdueUseCase
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEvent
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEventBus
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class MenuViewModel @Inject constructor(
     getTaskListsWithOverdue: GetTaskListsWithOverdueUseCase,
-    getDueTodayTasks: GetDueTodayTasksUseCase
+    getDueTodayTasks: GetDueTodayTasksUseCase,
+    private val uiEventBus: UiEventBus
 ) : ViewModel() {
-
     var taskLists by mutableStateOf<List<TaskListWithOverdue>>(emptyList())
         private set
 
@@ -38,4 +41,10 @@ class MenuViewModel @Inject constructor(
             }
             .launchIn(viewModelScope)
     }
+
+    fun navigateTo(route: String) {
+        viewModelScope.launch {
+            uiEventBus.send(UiEvent.Navigate(route))
+        }
+    }
 }

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

@@ -19,9 +19,9 @@ import javax.inject.Inject
 @HiltViewModel
 class TaskListViewModel @Inject constructor(
     getTasks: GetTasksForListUseCase,
+    savedStateHandle: SavedStateHandle,
     private val toggleTaskDone: ToggleTaskDoneUseCase,
     private val toggleTaskDeleted: ToggleTaskDeletedUseCase,
-    savedStateHandle: SavedStateHandle
 ) : ViewModel() {
 
     var tasks by mutableStateOf<List<Task>>(emptyList())

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

@@ -9,6 +9,8 @@ import com.wismna.geoffroy.donext.domain.model.Priority
 import com.wismna.geoffroy.donext.domain.model.Task
 import com.wismna.geoffroy.donext.domain.usecase.AddTaskUseCase
 import com.wismna.geoffroy.donext.domain.usecase.UpdateTaskUseCase
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEvent
+import com.wismna.geoffroy.donext.presentation.ui.events.UiEventBus
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import java.time.Instant
@@ -19,7 +21,8 @@ import javax.inject.Inject
 @HiltViewModel
 class TaskViewModel @Inject constructor(
     private val createTaskUseCase: AddTaskUseCase,
-    private val updateTaskUseCase: UpdateTaskUseCase
+    private val updateTaskUseCase: UpdateTaskUseCase,
+    private val uiEventBus: UiEventBus
 ) : ViewModel() {
 
     var title by mutableStateOf("")
@@ -38,10 +41,23 @@ class TaskViewModel @Inject constructor(
     private var editingTaskId: Long? = null
     private var taskListId: Long? = null
 
+    init {
+        viewModelScope.launch {
+            uiEventBus.events.collect { event ->
+                when (event) {
+                    is UiEvent.EditTask -> startEditTask(event.task)
+                    is UiEvent.CreateNewTask -> startNewTask(event.taskListId)
+                    is UiEvent.CloseTask -> reset()
+                    else -> {}
+                }
+            }
+        }
+    }
+
     fun screenTitle(): String = if (isDeleted) "Task details" else if (isEditing()) "Edit Task" else "New Task"
     fun isEditing(): Boolean = editingTaskId != null
 
-    fun startNewTask(selectedListId: Long) {
+    private fun startNewTask(selectedListId: Long) {
         editingTaskId = null
         taskListId = selectedListId
         title = ""
@@ -51,7 +67,7 @@ class TaskViewModel @Inject constructor(
         isDeleted = false
     }
 
-    fun startEditTask(task: Task) {
+    private fun startEditTask(task: Task) {
         editingTaskId = task.id
         taskListId = task.taskListId
         title = task.name
@@ -84,8 +100,6 @@ class TaskViewModel @Inject constructor(
             } else {
                 createTaskUseCase(taskListId!!, title, description, priority, dueDate)
             }
-            // reset state after save
-            reset()
             onDone?.invoke()
         }
     }