Feature: Error screen

app/build.gradle

@@ -2,6 +2,7 @@ plugins {
     id 'com.android.application'
     id("com.github.triplet.play") version "3.6.0"
     id 'kotlin-android'
+    id "com.google.firebase.crashlytics"
 }
 
 apply plugin: 'kotlin-parcelize'
@@ -60,6 +61,7 @@ dependencies {
     implementation project(":algorithms")
     implementation platform('com.google.firebase:firebase-bom:28.4.0')
     implementation 'com.google.firebase:firebase-analytics-ktx'
+    implementation "com.google.firebase:firebase-crashlytics"
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion"
     implementation 'androidx.activity:activity-ktx:1.8.0'
     implementation 'androidx.fragment:fragment-ktx:1.6.1'
@@ -69,8 +71,10 @@ dependencies {
     implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.6.2'
     testImplementation 'junit:junit:4.13.2'
+    testImplementation("io.mockk:mockk:1.13.9")
     testImplementation "org.mockito:mockito-core:4.8.1"
     testImplementation "org.mockito.kotlin:mockito-kotlin:4.0.0"
+    testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:1.8.0"
     androidTestImplementation 'androidx.test:core-ktx:1.5.0'
     androidTestImplementation 'androidx.test.ext:junit:1.1.5'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'

app/src/main/java/com/randomimagecreator/ImageCreator.kt

@@ -1,30 +1,35 @@
 package com.randomimagecreator
 
 import android.content.ContentResolver
-import android.graphics.Bitmap
-import android.graphics.Color
 import android.net.Uri
 import androidx.documentfile.provider.DocumentFile
 import com.randomimagecreator.algorithms.ImageCreating
 import com.randomimagecreator.algorithms.Mandelbrot
 import com.randomimagecreator.algorithms.Pixelated
 import com.randomimagecreator.algorithms.SierpinskiCarpet
 import com.randomimagecreator.algorithms.SolidColor
+import com.randomimagecreator.common.BitmapCreator
 import com.randomimagecreator.common.HsvToHexConverter
 import com.randomimagecreator.common.ImageSaver
 import com.randomimagecreator.configuration.Configuration
 import com.randomimagecreator.configuration.ImagePattern
 import com.randomimagecreator.result.ImageCreationResult
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
 import kotlin.system.measureTimeMillis
 
-class ImageCreator {
-    var bitmapSaveNotifier: MutableSharedFlow<Nothing?> = MutableSharedFlow()
+class ImageCreator(
+    private val imageSaver: ImageSaver = ImageSaver(),
+    private val bitmapCreator: BitmapCreator = BitmapCreator()
+) {
+    val bitmapSafeNotifier get() = _bitmapSaveNotifier.asSharedFlow()
+    private var _bitmapSaveNotifier: MutableSharedFlow<Nothing?> = MutableSharedFlow()
+
     suspend fun create(
         contentResolver: ContentResolver,
         saveDirectory: DocumentFile,
         configuration: Configuration
-    ): ImageCreationResult {
+    ): Result<ImageCreationResult> {
         val width = configuration.width
         val height = configuration.height
         val algorithm: ImageCreating = when (configuration.pattern) {
@@ -38,38 +43,47 @@ class ImageCreator {
         val images = mutableListOf<Array<String>>()
         val creationDurationInMilliseconds = measureTimeMillis {
             for (i in 0..<configuration.amount) {
-                val image = algorithm.createImage()
+                val image = try {
+                    algorithm.createImage()
+                } catch (exception: Exception) {
+                    return Result.failure(ImageCreatingAlgorithmError())
+                }
                 val flattenedImage = image.flatMap { it.asIterable() }.toTypedArray()
                 images.add(flattenedImage)
             }
         }
 
-        val bitmaps = images.map { bitmap ->
-            Bitmap.createBitmap(
-                bitmap.map { pixel -> Color.parseColor(pixel) }.toIntArray(),
-                configuration.width,
-                configuration.height,
-                Bitmap.Config.ARGB_8888
-            ).also {
-                it.setHasAlpha(false)
+        val bitmaps = try {
+            images.map { bitmap ->
+                bitmapCreator.create(bitmap, configuration.width, configuration.height)
             }
+        } catch (exception: IllegalArgumentException) {
+            return Result.failure(BitmapCreationError())
         }
 
         val uris = mutableListOf<Uri>()
         val saveDurationInMilliseconds = measureTimeMillis {
             for (bitmap in bitmaps) {
-                bitmapSaveNotifier.emit(null)
-                val uri = ImageSaver.saveBitmap(
-                    bitmap,
-                    contentResolver,
-                    saveDirectory,
-                    configuration.format,
-                )
+                val uri = try {
+                    imageSaver.saveBitmap(
+                        bitmap,
+                        contentResolver,
+                        saveDirectory,
+                        configuration.format,
+                    )
+                } catch (exception: Exception) {
+                    return Result.failure(BitmapSaveError())
+                }
+                _bitmapSaveNotifier.emit(null)
                 uri?.let { uris.add(it) }
             }
         }
 
         val durationInMilliseconds = creationDurationInMilliseconds + saveDurationInMilliseconds
-        return ImageCreationResult(uris, durationInMilliseconds)
+        return Result.success(ImageCreationResult(uris, durationInMilliseconds))
     }
 }
+
+class ImageCreatingAlgorithmError : Error()
+class BitmapCreationError : Error()
+class BitmapSaveError : Error()

app/src/main/java/com/randomimagecreator/MainActivity.kt

@@ -8,9 +8,11 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentManager
 import androidx.lifecycle.lifecycleScope
+import com.google.firebase.FirebaseApp
 import com.randomimagecreator.choosesavedirectory.ChooseSaveDirectoryFragment
 import com.randomimagecreator.common.Analytics
 import com.randomimagecreator.configuration.ConfigurationFragment
+import com.randomimagecreator.error.ErrorFragment
 import com.randomimagecreator.loading.LoadingFragment
 import com.randomimagecreator.result.ResultFragment
 import kotlinx.coroutines.launch
@@ -21,6 +23,7 @@ class MainActivity : AppCompatActivity(R.layout.activity_main) {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Analytics.setup()
+        FirebaseApp.initializeApp(applicationContext)
         replaceFragment(ConfigurationFragment(), isRootFragment = true)
         lifecycleScope.launch {
             viewModel.navigationRequestBroadcaster.collect(::onNavigationRequest)
@@ -54,6 +57,10 @@ class MainActivity : AppCompatActivity(R.layout.activity_main) {
                 replaceFragment(LoadingFragment(), LoadingFragment.TAG)
             }
 
+            is Screen.Error -> {
+                replaceFragment(ErrorFragment())
+            }
+
             is Screen.Result -> {
                 replaceFragment(ResultFragment())
             }

app/src/main/java/com/randomimagecreator/MainViewModel.kt

@@ -3,11 +3,11 @@ package com.randomimagecreator
 import android.content.Context
 import android.net.Uri
 import android.provider.OpenableColumns
-import android.util.Log
 import androidx.core.database.getStringOrNull
 import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.google.firebase.crashlytics.FirebaseCrashlytics
 import com.randomimagecreator.common.errors.SaveDirectoryMissingError
 import com.randomimagecreator.common.extensions.query
 import com.randomimagecreator.configuration.Configuration
@@ -19,7 +19,6 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.launch
 
-private const val TAG = "MainViewModel"
 
 /**
  * ViewModel used throughout the app.
@@ -61,15 +60,18 @@ class MainViewModel : ViewModel() {
         val saveDirectoryUri = configuration.saveDirectory ?: throw SaveDirectoryMissingError()
         val saveDirectory =
             DocumentFile.fromTreeUri(context, saveDirectoryUri) ?: throw SaveDirectoryMissingError()
-
+        val config = configuration.copy(width = -1)
         viewModelScope.launch(Dispatchers.IO) {
-            try {
-                imageCreationResult =
-                    imageCreator.create(context.contentResolver, saveDirectory, configuration)
-                navigationRequestBroadcaster.emit(Screen.Result)
-            } catch (exception: Exception) {
-                Log.e(TAG, "", exception)
-            }
+            imageCreator.create(context.contentResolver, saveDirectory, config).fold(
+                onSuccess = {
+                    imageCreationResult = it
+                    navigationRequestBroadcaster.emit(Screen.Result)
+                },
+                onFailure = {
+                    FirebaseCrashlytics.getInstance().recordException(it)
+                    navigationRequestBroadcaster.emit(Screen.Error)
+                }
+            )
         }
     }
 

app/src/main/java/com/randomimagecreator/Screen.kt

@@ -19,6 +19,11 @@ sealed class Screen {
      */
     data object Loading : Screen()
 
+    /**
+     * Screen showing an error occurred during image generation.
+     */
+    data object Error : Screen()
+
     /**
      * Screen showing images that got created.
      */

app/src/main/java/com/randomimagecreator/common/BitmapCreator.kt

@@ -0,0 +1,24 @@
+package com.randomimagecreator.common
+
+import android.graphics.Bitmap
+import android.graphics.Color
+
+/**
+ * Wrapper class for creating Bitmaps.
+ */
+class BitmapCreator {
+    fun create(
+        bitmap: Array<String>,
+        width: Int,
+        height: Int
+    ): Bitmap {
+        return Bitmap.createBitmap(
+            bitmap.map { pixel -> Color.parseColor(pixel) }.toIntArray(),
+            width,
+            height,
+            Bitmap.Config.ARGB_8888
+        ).also {
+            it.setHasAlpha(false)
+        }
+    }
+}

app/src/main/java/com/randomimagecreator/common/ImageSaver.kt

@@ -1,7 +1,6 @@
 package com.randomimagecreator.common
 
 import android.content.ContentResolver
-import android.content.Context
 import android.graphics.Bitmap
 import android.net.Uri
 import androidx.documentfile.provider.DocumentFile
@@ -10,39 +9,15 @@ import com.randomimagecreator.configuration.ImageFileFormat
 /**
  * Helper class for saving images.
  */
-object ImageSaver {
+class ImageSaver {
     /**
-     * Saves the given array of bitmaps to the provided [directory].
+     * Saves the given bitmap to the provided [saveDirectory].
      *
-     * @param bitmaps           A list of all bitmaps to save.
-     * @param context           The context of the caller.
-     * @param directory         Directory selected by user for saving.
+     * @param bitmap            Bitmap to save.
+     * @param contentResolver   Resolver for creating the outputstream.
+     * @param saveDirectory     Directory selected by user for saving.
      * @param format            Format to save the bitmap in.
-     * @param notifier          Notifier that emits the amount of saved bitmaps.
      */
-    fun saveBitmaps(
-        bitmaps: List<Bitmap>,
-        context: Context,
-        directory: Uri,
-        format: ImageFileFormat,
-//        notifier: MutableSharedFlow<Nothing?>
-    ): List<Uri> {
-        val rootDocumentFile = DocumentFile.fromTreeUri(context, directory)
-        assert(rootDocumentFile != null) { "root document file shouldn't be null" }
-
-        val bitmapUris = mutableListOf<Uri>()
-
-        for (bitmap in bitmaps) {
-            saveBitmap(bitmap, context.contentResolver, rootDocumentFile!!, format)?.let {
-                bitmapUris.add(it)
-//                scope.launch {
-//                    notifier.emit(null)
-//                }
-            }
-        }
-        return bitmapUris
-    }
-
     fun saveBitmap(
         bitmap: Bitmap,
         contentResolver: ContentResolver,

app/src/main/java/com/randomimagecreator/error/ErrorFragment.kt

@@ -0,0 +1,9 @@
+package com.randomimagecreator.error
+
+import androidx.fragment.app.Fragment
+import com.randomimagecreator.R
+
+/**
+ * Provides feedback to the user an error occurred during image generation.
+ */
+class ErrorFragment : Fragment(R.layout.fragment_error)

app/src/main/java/com/randomimagecreator/loading/LoadingFragment.kt

@@ -23,7 +23,7 @@ class LoadingFragment : Fragment(R.layout.fragment_loading) {
         numberOfSavedImagesTextField = view.findViewById(R.id.loading_saved_amount)
 
         viewLifecycleOwner.lifecycleScope.launch {
-            viewModel.imageCreator.bitmapSaveNotifier.collect {
+            viewModel.imageCreator.bitmapSafeNotifier.collect {
                 numberOfSavedImages++
                 updateNumberOfSavedImages()
             }

app/src/main/res/layout/fragment_error.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.constraintlayout.widget.Guideline
+        android:id="@+id/guideline_begin"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        app:layout_constraintGuide_begin="28dp" />
+
+    <androidx.constraintlayout.widget.Guideline
+        android:id="@+id/guideline_end"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        app:layout_constraintGuide_end="28dp" />
+
+    <include
+        android:id="@+id/shared_logo"
+        layout="@layout/shared_top_logo"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <TextView
+        android:id="@+id/error_title"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="24dp"
+        android:text="@string/error_title"
+        android:textSize="18sp"
+        android:textStyle="bold"
+        android:textAlignment="center"
+        app:layout_constraintEnd_toStartOf="@id/guideline_end"
+        app:layout_constraintStart_toEndOf="@id/guideline_begin"
+        app:layout_constraintTop_toBottomOf="@id/shared_logo"
+        app:layout_constraintBottom_toBottomOf="parent"/>
+
+    <TextView
+        android:id="@+id/error_instructions"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:text="@string/error_instructions"
+        android:textSize="14sp"
+        android:textStyle="normal"
+        android:textAlignment="center"
+        android:paddingTop="4dp"
+        app:layout_constraintEnd_toStartOf="@id/guideline_end"
+        app:layout_constraintStart_toEndOf="@id/guideline_begin"
+        app:layout_constraintTop_toBottomOf="@id/error_title" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values/strings.xml

@@ -34,4 +34,6 @@
     <string name="image_creator_pixelated">Pixelated</string>
     <string name="image_creator_mandelbrot">Mandelbrot</string>
     <string name="image_creator_sierpinski">Sierpinski carpet</string>
+    <string name="error_title">An error occurred :(</string>
+    <string name="error_instructions">Please try it again with a different configuration</string>
 </resources>