Fix navigation issue when navigating back to a deleted list

Some refactoring

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

@@ -15,7 +15,6 @@ import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.wismna.geoffroy.donext.domain.model.Task
 import com.wismna.geoffroy.donext.presentation.viewmodel.DueTodayViewModel
-import com.wismna.geoffroy.donext.presentation.viewmodel.TaskItemViewModel
 
 @Composable
 fun DueTodayTasksScreen(
@@ -41,7 +40,7 @@ fun DueTodayTasksScreen(
             items(tasks, key = { it.id!! }) { task ->
                 TaskItemScreen(
                     modifier = Modifier.animateItem(),
-                    viewModel = TaskItemViewModel(task),
+                    task = task,
                     onTaskClick = { onTaskClick(task) },
                     onSwipeLeft = {
                         viewModel.updateTaskDone(task.id!!)

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

@@ -18,6 +18,7 @@ import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DrawerState
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.LocalContentColor
@@ -31,7 +32,10 @@ import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.rememberDrawerState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -60,7 +64,7 @@ fun MainScreen(
     val navController = rememberNavController()
     val drawerState = rememberDrawerState(DrawerValue.Closed)
     val scope = rememberCoroutineScope()
-    // TODO: find a way to get rid of this
+    // TODO: find a way to do this better
     val taskViewModel: TaskViewModel = hiltViewModel()
 
     if (viewModel.isLoading) {
@@ -154,9 +158,13 @@ fun AppContent(
         floatingActionButton = {
             when (val dest = viewModel.currentDestination) {
                 is AppDestination.TaskList -> {
-                    TaskListFab(
-                        taskListId = dest.taskListId,
-                        showBottomSheet = { viewModel.showTaskSheet = it }
+                    ExtendedFloatingActionButton(
+                        onClick = {
+                            taskViewModel.startNewTask(dest.taskListId)
+                            viewModel.showTaskSheet = true
+                        },
+                        icon = { Icon(Icons.Filled.Add, "Create a task.") },
+                        text = { Text("Create a task") },
                     )
                 }
                 else -> null
@@ -192,7 +200,16 @@ fun AppContent(
                         type = NavType.LongType
                     })
                 ) { navBackStackEntry ->
-                    // TODO: when task list has been deleted, we should not navigate to it event if in the stack
+                    val taskListId = navBackStackEntry.arguments?.getLong("taskListId") ?: return@composable
+                    val listExists by remember(taskListId, viewModel.destinations) {
+                        derivedStateOf { viewModel.doesListExist(taskListId) }
+                    }
+                    LaunchedEffect(listExists) {
+                        if (!viewModel.doesListExist(taskListId)) {
+                            navController.popBackStack()
+                        }
+                    }
+
                     val taskListViewModel: TaskListViewModel = hiltViewModel(navBackStackEntry)
                     TaskListScreen(
                         viewModel = taskListViewModel,

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

@@ -31,7 +31,6 @@ import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.wismna.geoffroy.donext.domain.model.Task
 import com.wismna.geoffroy.donext.presentation.viewmodel.RecycleBinViewModel
-import com.wismna.geoffroy.donext.presentation.viewmodel.TaskItemViewModel
 
 @Composable
 fun RecycleBinScreen(
@@ -77,7 +76,7 @@ fun RecycleBinScreen(
             items(items, key = { it.task.id!! }) { item ->
                 TaskItemScreen(
                     modifier = Modifier.animateItem(),
-                    viewModel = TaskItemViewModel(item.task),
+                    task = item.task,
                     onTaskClick = { onTaskClick(item.task) },
                     onSwipeLeft = {
                         viewModel.restore(item.task.id!!)

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

@@ -38,16 +38,18 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import com.wismna.geoffroy.donext.domain.model.Priority
+import com.wismna.geoffroy.donext.domain.model.Task
 import com.wismna.geoffroy.donext.presentation.viewmodel.TaskItemViewModel
 
 @Composable
 fun TaskItemScreen(
     modifier: Modifier = Modifier,
-    viewModel: TaskItemViewModel,
+    task: Task,
     onTaskClick: (taskId: Long) -> Unit,
     onSwipeLeft: () -> Unit,
     onSwipeRight: () -> Unit
 ) {
+    val viewModel = TaskItemViewModel(task)
     // TODO: change this
     val dismissState = rememberSwipeToDismissBoxState(
         confirmValueChange = {

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

@@ -21,7 +21,6 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.wismna.geoffroy.donext.domain.model.Task
-import com.wismna.geoffroy.donext.presentation.viewmodel.TaskItemViewModel
 import com.wismna.geoffroy.donext.presentation.viewmodel.TaskListViewModel
 import com.wismna.geoffroy.donext.presentation.viewmodel.TaskViewModel
 
@@ -50,7 +49,7 @@ fun TaskListScreen(
         ) { task ->
             TaskItemScreen(
                 modifier = Modifier.animateItem(),
-                viewModel = TaskItemViewModel(task),
+                task = task,
                 onTaskClick = { onTaskClick(task) },
                 onSwipeLeft = {
                     viewModel.updateTaskDone(task.id!!, true)
@@ -81,7 +80,7 @@ fun TaskListScreen(
         ) { task ->
             TaskItemScreen(
                 modifier = Modifier.animateItem(),
-                viewModel = TaskItemViewModel(task),
+                task = task,
                 onTaskClick = { onTaskClick(task) },
                 onSwipeLeft = {
                     viewModel.updateTaskDone(task.id!!, false)
@@ -95,20 +94,4 @@ fun TaskListScreen(
         }
 
     }
-}
-
-@Composable
-fun TaskListFab(
-    taskListId: Long,
-    viewModel: TaskViewModel = hiltViewModel(),
-    showBottomSheet: (Boolean) -> Unit = {}
-) {
-    ExtendedFloatingActionButton(
-        onClick = {
-            viewModel.startNewTask(taskListId)
-            showBottomSheet(true)
-        },
-        icon = { Icon(Icons.Filled.Add, "Create a task.") },
-        text = { Text("Create a task") },
-    )
 }

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

@@ -61,4 +61,10 @@ class MainViewModel @Inject constructor(
             }
         } ?: startDestination
     }
+
+    fun doesListExist(taskListId: Long): Boolean {
+        return destinations.any { dest ->
+            dest is AppDestination.TaskList && dest.taskListId == taskListId
+        }
+    }
 }