Migrate ResultsScreen to use Nav3

app/src/main/java/com/android/developers/androidify/navigation/MainNavigation.kt

@@ -32,15 +32,21 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.IntOffset
+import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.viewmodel.navigation3.rememberViewModelStoreNavEntryDecorator
 import androidx.navigation3.runtime.entry
 import androidx.navigation3.runtime.entryProvider
 import androidx.navigation3.runtime.rememberSavedStateNavEntryDecorator
 import androidx.navigation3.ui.NavDisplay
 import com.android.developers.androidify.camera.CameraPreviewScreen
 import com.android.developers.androidify.creation.CreationScreen
+import com.android.developers.androidify.creation.CreationViewModel
+import com.android.developers.androidify.customize.CustomizeAndExportScreen
+import com.android.developers.androidify.customize.CustomizeExportViewModel
 import com.android.developers.androidify.home.AboutScreen
 import com.android.developers.androidify.home.HomeScreen
+import com.android.developers.androidify.results.ResultsScreen
+import com.android.developers.androidify.results.ResultsViewModel
 import com.android.developers.androidify.theme.transitions.ColorSplashTransitionScreen
 import com.google.android.gms.oss.licenses.OssLicensesMenuActivity
 
@@ -92,14 +98,20 @@ fun MainNavigation() {
                 CameraPreviewScreen(
                     onImageCaptured = { uri ->
                         backStack.removeAll { it is Create }
-                        backStack.add(Create(uri.toString()))
+                        backStack.add(Create(uri))
                         backStack.removeAll { it is Camera }
                     },
                 )
             }
             entry<Create> { createKey ->
+                val creationViewModel = hiltViewModel<CreationViewModel, CreationViewModel.Factory>(
+                    creationCallback = {    factory ->
+                        factory.create(
+                            originalImageUrl = createKey.fileName
+                        )
+                    }
+                )
                 CreationScreen(
-                    createKey.fileName,
                     onCameraPressed = {
                         backStack.removeAll { it is Camera }
                         backStack.add(Camera)
@@ -110,6 +122,65 @@ fun MainNavigation() {
                     onAboutPressed = {
                         backStack.add(About)
                     },
+                    onImageCreated = { resultImageUri, prompt, originalImageUri ->
+                        backStack.removeAll{ it is Result}
+                        backStack.add(
+                            Result(
+                                resultImageUri = resultImageUri,
+                                prompt = prompt,
+                                originalImageUri = originalImageUri
+                            )
+                        )
+                    },
+                    creationViewModel = creationViewModel
+                )
+            }
+            entry<Result> { resultKey ->
+                val resultsViewModel = hiltViewModel<ResultsViewModel, ResultsViewModel.Factory>(
+                    creationCallback = { factory ->
+                        factory.create(
+                            resultImageUrl = resultKey.resultImageUri,
+                            originalImageUrl = resultKey.originalImageUri,
+                            promptText = resultKey.prompt
+                        )
+                    }
+                )
+                ResultsScreen(
+                    onNextPress = { resultImageUri, originalImageUri ->
+                        backStack.removeAll{ it is Result}
+                        backStack.add(
+                            CustomizeExport(
+                                resultImageUri = resultImageUri,
+                                originalImageUri = originalImageUri
+                            )
+                        )
+                    },
+                    onAboutPress = {
+                        backStack.add(About)
+                    },
+                    onBackPress = {
+                        backStack.removeLastOrNull()
+                    },
+                    viewModel = resultsViewModel
+                )
+            }
+            entry<CustomizeExport> { shareKey ->
+                val customizeExportViewModel = hiltViewModel<CustomizeExportViewModel, CustomizeExportViewModel.Factory>(
+                    creationCallback = { factory ->
+                        factory.create(
+                            resultImageUrl = shareKey.resultImageUri,
+                            originalImageUrl = shareKey.originalImageUri
+                        )
+                    }
+                )
+                CustomizeAndExportScreen(
+                    onBackPress = {
+                        backStack.removeLastOrNull()
+                    },
+                    onInfoPress = {
+                        backStack.add(About)
+                    },
+                    viewModel = customizeExportViewModel
                 )
             }
             entry<About> {

app/src/main/java/com/android/developers/androidify/navigation/NavigationRoutes.kt

@@ -17,6 +17,7 @@
 
 package com.android.developers.androidify.navigation
 
+import android.net.Uri
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.Serializable
 
@@ -26,10 +27,39 @@ sealed interface NavigationRoute
 data object Home : NavigationRoute
 
 @Serializable
-data class Create(val fileName: String? = null, val prompt: String? = null) : NavigationRoute
+data class Create(
+    @Serializable(with = UriSerializer::class) val fileName: Uri? = null,
+    val prompt: String? = null
+) : NavigationRoute
 
 @Serializable
 object Camera : NavigationRoute
 
 @Serializable
 object About : NavigationRoute
+
+/**
+ * Represents the result of an image generation process, used for navigation.
+ *
+ * @param resultImageUri The URI of the generated image.
+ * @param originalImageUri The URI of the original image used as a base for generation, if any.
+ * @param prompt The text prompt used to generate the image, if any.
+ */
+@Serializable
+data class Result(
+    @Serializable(with = UriSerializer::class) val resultImageUri: Uri,
+    @Serializable(with = UriSerializer::class) val originalImageUri: Uri? = null,
+    val prompt: String? = null
+) : NavigationRoute
+
+/**
+ * Represents the navigation route to the screen for customizing and exporting a generated image.
+ *
+ * @param resultImageUri The URI of the generated image to be customized.
+ * @param originalImageUri The URI of the original image, passed along for context.
+ */
+@Serializable
+data class CustomizeExport(
+    @Serializable(with = UriSerializer::class) val resultImageUri: Uri,
+    @Serializable(with = UriSerializer::class) val originalImageUri: Uri?
+) : NavigationRoute

app/src/main/java/com/android/developers/androidify/navigation/UriSerializer.kt

@@ -0,0 +1,21 @@
+package com.android.developers.androidify.navigation
+
+import android.net.Uri
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import androidx.core.net.toUri
+
+object UriSerializer: KSerializer<Uri> {
+    override val descriptor: SerialDescriptor =
+        PrimitiveSerialDescriptor("Uri", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: Uri) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): Uri = decoder.decodeString().toUri()
+}

core/testing/src/main/java/com/android/developers/testing/data/TestFileProvider.kt

@@ -64,4 +64,8 @@ class TestFileProvider : LocalFileProvider {
     ): Uri {
         TODO("Not yet implemented")
     }
+
+    override suspend fun loadBitmapFromUri(uri: Uri): Bitmap? {
+        TODO("Not yet implemented")
+    }
 }

core/util/src/main/java/com/android/developers/androidify/util/LocalFileProvider.kt

@@ -18,6 +18,7 @@ package com.android.developers.androidify.util
 import android.app.Application
 import android.content.ContentValues
 import android.graphics.Bitmap
+import android.graphics.BitmapFactory
 import android.net.Uri
 import android.os.Build
 import android.os.Environment
@@ -53,6 +54,9 @@ interface LocalFileProvider {
 
     @WorkerThread
     suspend fun saveUriToSharedStorage(inputUri: Uri, fileName: String, mimeType: String): Uri
+
+    @WorkerThread
+    suspend fun loadBitmapFromUri(uri: Uri): Bitmap?
 }
 
 @Singleton
@@ -120,6 +124,20 @@ class LocalFileProviderImpl @Inject constructor(
         return@withContext newUri
     }
 
+    override suspend fun loadBitmapFromUri(uri: Uri): Bitmap? {
+        return withContext(ioDispatcher) {
+            try {
+                application.contentResolver.openInputStream(uri)?.use {
+                    return@withContext BitmapFactory.decodeStream(it)
+                }
+                null
+            } catch (e: Exception) {
+                e.printStackTrace()
+                null
+            }
+        }
+    }
+
     @Throws(IOException::class)
     @WorkerThread
     private fun saveFileToUri(file: File, uri: Uri) {

feature/creation/src/main/java/com/android/developers/androidify/creation/CreationScreen.kt

@@ -92,6 +92,7 @@ import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.material3.ripple
 import androidx.compose.material3.toShape
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -123,6 +124,11 @@ import androidx.core.net.toUri
 import androidx.graphics.shapes.RoundedPolygon
 import androidx.graphics.shapes.rectangle
 import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.compose.LifecycleResumeEffect
+import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import coil3.compose.AsyncImage
 import coil3.request.ImageRequest
@@ -158,32 +164,41 @@ import com.android.developers.androidify.creation.R as CreationR
 
 @Composable
 fun CreationScreen(
-    fileName: String? = null,
-    creationViewModel: CreationViewModel = hiltViewModel(),
+    creationViewModel: CreationViewModel,
     isMedium: Boolean = isAtLeastMedium(),
     onCameraPressed: () -> Unit = {},
     onBackPressed: () -> Unit,
     onAboutPressed: () -> Unit,
+    onImageCreated: (resultImageUri: Uri, prompt: String?, originalImageUri: Uri?) -> Unit,
 ) {
     val uiState by creationViewModel.uiState.collectAsStateWithLifecycle()
     BackHandler(
         enabled = uiState.screenState != ScreenState.EDIT,
     ) {
         creationViewModel.onBackPress()
     }
-    LaunchedEffect(Unit) {
-        if (fileName != null) {
-            creationViewModel.onImageSelected(fileName.toUri())
-        } else {
-            creationViewModel.onImageSelected(null)
-        }
-    }
     val pickMedia = rememberLauncherForActivityResult(PickVisualMedia()) { uri ->
         if (uri != null) {
             creationViewModel.onImageSelected(uri)
         }
     }
     val snackbarHostState by creationViewModel.snackbarHostState.collectAsStateWithLifecycle()
+
+    LaunchedEffect(uiState.resultBitmapUri) {
+        uiState.resultBitmapUri?.let { resultBitmapUri ->
+            onImageCreated(
+                resultBitmapUri,
+                uiState.descriptionText.text.toString(),
+                if (uiState.selectedPromptOption == PromptType.PHOTO) {
+                    uiState.imageUri
+                } else {
+                    null
+                }
+            )
+            creationViewModel.onResultDisplayed()
+        }
+    }
+
     when (uiState.screenState) {
         ScreenState.EDIT -> {
             EditScreen(
@@ -211,46 +226,6 @@ fun CreationScreen(
                 },
             )
         }
-
-        ScreenState.RESULT -> {
-            val prompt = uiState.descriptionText.text.toString()
-            val key = if (uiState.descriptionText.text.isBlank()) {
-                uiState.imageUri.toString()
-            } else {
-                prompt
-            }
-            ResultsScreen(
-                uiState.resultBitmap!!,
-                if (uiState.selectedPromptOption == PromptType.PHOTO) {
-                    uiState.imageUri
-                } else {
-                    null
-                },
-                promptText = prompt,
-                viewModel = hiltViewModel(key = key),
-                onAboutPress = onAboutPressed,
-                onBackPress = onBackPressed,
-                onNextPress = creationViewModel::customizeExportClicked,
-            )
-        }
-
-        ScreenState.CUSTOMIZE -> {
-            val prompt = uiState.descriptionText.text.toString()
-            val key = if (uiState.descriptionText.text.isBlank()) {
-                uiState.imageUri.toString()
-            } else {
-                prompt
-            }
-            uiState.resultBitmap?.let { bitmap ->
-                CustomizeAndExportScreen(
-                    resultImage = bitmap,
-                    originalImageUri = uiState.imageUri,
-                    onBackPress = onBackPressed,
-                    onInfoPress = onAboutPressed,
-                    viewModel = hiltViewModel<CustomizeExportViewModel>(key = key),
-                )
-            }
-        }
     }
 }