Handle delete properly (#141)

* When a program is deleted, make sure its screens are popped from the backstack (as they are re-visited)
jblebrun · Oct 29, 2024 · e0e2281 · e0e2281
1 parent a153e03
commit e0e2281
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Showing 5 changed files with 41 additions and 24 deletions.
diff --git a/app/src/main/java/com/emerjbl/ultra8/data/ProgramStore.kt b/app/src/main/java/com/emerjbl/ultra8/data/ProgramStore.kt
@@ -32,6 +32,9 @@ interface ProgramDao {
     @Query("SELECT name, cyclesPerTick from program ORDER BY name")
     fun allFlow(): Flow<List<Program>>
 
+    @Query("SELECT * from program where name == :name limit 1")
+    fun nameFlow(name: String): Flow<Program?>
+
     @Query("SELECT * from program where name == :name limit 1")
     suspend fun withData(name: String): Program?
 
@@ -45,19 +48,15 @@ interface ProgramDao {
     suspend fun add(program: Program)
 }
 
-sealed interface SelectedProgram {
-    data object Loading : SelectedProgram
-    data object None : SelectedProgram
-    data class Program(val programName: String) : SelectedProgram
-}
-
 /** The store of programs that Ultra8 can run. */
 class ProgramStore(
     private val context: Context,
     private val programDao: ProgramDao,
 ) {
     fun programsFlow(): Flow<List<Program>> = programDao.allFlow()
 
+    fun nameFlow(name: String): Flow<Program?> = programDao.nameFlow(name)
+
     suspend fun add(program: Program) {
         programDao.add(program)
     }

diff --git a/app/src/main/java/com/emerjbl/ultra8/ui/gameplay/PlayGameViewModel.kt b/app/src/main/java/com/emerjbl/ultra8/ui/gameplay/PlayGameViewModel.kt
@@ -34,6 +34,7 @@ class PlayGameViewModel(
     private val programStore: ProgramStore,
 ) : ViewModel() {
     private var machine = newMachine(byteArrayOf())
+    val program = programStore.nameFlow(programName)
 
     val running = MutableStateFlow<Boolean>(false)
     val halted = MutableStateFlow<Halt?>(null)
@@ -83,19 +84,19 @@ class PlayGameViewModel(
 
     suspend fun runMachine() {
         machine = withContext(Dispatchers.IO) {
-            val savedState = chip8StateStore.findState(programName)
             val program = programStore.withData(programName)
-            if (program != null) {
-                cyclesPerTick.value = program.cyclesPerTick
+            if (program == null) {
+                Log.i("Chip8", "Could not find $programName at all")
+                return@withContext null
             }
+
+            cyclesPerTick.value = program.cyclesPerTick
+            val savedState = chip8StateStore.findState(programName)
             if (savedState != null) {
                 Log.i("Chip8", "Restored save state for $programName")
                 newMachine(savedState)
-            } else if (program != null) {
-                newMachine(program.data!!)
             } else {
-                Log.i("Chip8", "Could not find $programName at all")
-                null
+                newMachine(program.data!!)
             }
         } ?: return
 

diff --git a/app/src/main/java/com/emerjbl/ultra8/ui/gameplay/PlayScreen.kt b/app/src/main/java/com/emerjbl/ultra8/ui/gameplay/PlayScreen.kt
@@ -18,13 +18,15 @@ import androidx.lifecycle.ViewModelStoreOwner
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.emerjbl.ultra8.ui.gameplay.input.onKeyEvent
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
 
 @Composable
 fun PlayScreen(
     programName: String,
     gameShouldRun: Boolean,
     resetEvents: Flow<Unit>,
     onDrawerOpen: () -> Unit,
+    onProgramGone: () -> Unit,
     title: String = programName,
 ) {
     val viewModel =
@@ -36,6 +38,13 @@ fun PlayScreen(
             factory = PlayGameViewModel.Factory
         )
 
+    // Listen for program disappearance
+    LaunchedEffect(viewModel.program) {
+        viewModel.program.first { it == null }
+        println("Program disappeared!")
+        onProgramGone()
+    }
+
     // Collect reset events from above
     LaunchedEffect(resetEvents) {
         resetEvents.collect {

diff --git a/app/src/main/java/com/emerjbl/ultra8/ui/loading/InitialLoadScreen.kt b/app/src/main/java/com/emerjbl/ultra8/ui/loading/InitialLoadScreen.kt
@@ -15,11 +15,18 @@ fun InitialLoadScreen(
     val programCount = viewModel.programs.collectAsState(null).value
     when {
         programCount == null -> Unit
-        programCount.size == 0 -> onCatalog()
-        else -> onDrawerOpen()
+        programCount.size == 0 -> {
+            println("No programs, show catalog")
+            onCatalog()
+        }
+
+        else -> {
+            println("Some programs, show drawer")
+            onDrawerOpen()
+        }
     }
 
     // Just show a blank play screen while loading.
-    PlayScreen("", false, flowOf(), onDrawerOpen, "<- Choose a game")
+    PlayScreen("", false, flowOf(), onDrawerOpen, {}, "<- Choose a game")
 
 }
diff --git a/app/src/main/java/com/emerjbl/ultra8/ui/navigation/Ultra8NavHost.kt b/app/src/main/java/com/emerjbl/ultra8/ui/navigation/Ultra8NavHost.kt
@@ -28,13 +28,7 @@ fun Ultra8NavHost(
             InitialLoadScreen(
                 onDrawerOpen,
                 onCatalog = {
-                    navController.navigate(Catalog) {
-                        // https://issuetracker.google.com/issues/370694831
-                        @SuppressLint("RestrictedApi")
-                        popUpTo(InitialLoad) {
-                            inclusive = true
-                        }
-                    }
+                    navController.navigate(Catalog)
                 },
             )
         }
@@ -44,7 +38,7 @@ fun Ultra8NavHost(
                     navController.navigate(PlayGame(it)) {
                         // https://issuetracker.google.com/issues/370694831
                         @SuppressLint("RestrictedApi")
-                        popUpTo(InitialLoad) {
+                        popUpTo(Catalog) {
                             inclusive = true
                         }
                     }
@@ -64,6 +58,13 @@ fun Ultra8NavHost(
                 programName = routeProgram,
                 gameShouldRun = gameShouldRun,
                 resetEvents = resetEvents,
+                onProgramGone = {
+                    println("$routeProgram GONE!")
+                    if (!navController.popBackStack()) {
+                        println("Couldn't pop...")
+                        navController.navigate(InitialLoad)
+                    }
+                },
                 onDrawerOpen = onDrawerOpen,
             )
         }