ImageViewer Android return back key (#2996)

examples/imageviewer/androidApp/src/androidMain/kotlin/example/imageviewer/MainActivity.kt

@@ -1,15 +1,29 @@
 package example.imageviewer
 
 import android.os.Bundle
+import androidx.activity.addCallback
 import androidx.activity.compose.setContent
 import androidx.appcompat.app.AppCompatActivity
 import example.imageviewer.view.ImageViewerAndroid
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
 
 class MainActivity : AppCompatActivity() {
+
+    val externalEvents = MutableSharedFlow<ExternalImageViewerEvent>(
+        replay = 0,
+        extraBufferCapacity = 1,
+        onBufferOverflow = BufferOverflow.DROP_OLDEST,
+    )
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
-            ImageViewerAndroid()
+            ImageViewerAndroid(externalEvents)
+        }
+        onBackPressedDispatcher.addCallback {
+            externalEvents.tryEmit(ExternalImageViewerEvent.ReturnBack)
         }
     }
+
 }

examples/imageviewer/shared/src/androidMain/kotlin/example/imageviewer/view/ImageViewer.android.kt

@@ -7,28 +7,41 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.platform.LocalContext
-import example.imageviewer.*
+import example.imageviewer.Dependencies
+import example.imageviewer.ExternalImageViewerEvent
+import example.imageviewer.ImageViewerCommon
+import example.imageviewer.Notification
+import example.imageviewer.PopupNotification
+import example.imageviewer.SharePicture
 import example.imageviewer.filter.PlatformContext
+import example.imageviewer.ioDispatcher
 import example.imageviewer.model.PictureData
 import example.imageviewer.storage.AndroidImageStorage
 import example.imageviewer.style.ImageViewerTheme
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
 
 @Composable
-fun ImageViewerAndroid() {
+fun ImageViewerAndroid(externalEvents: Flow<ExternalImageViewerEvent>) {
     val context: Context = LocalContext.current
     val ioScope = rememberCoroutineScope { ioDispatcher }
-    val dependencies = remember(context, ioScope) { getDependencies(context, ioScope) }
+    val dependencies = remember(context, ioScope) {
+        getDependencies(context, ioScope, externalEvents)
+    }
     ImageViewerTheme {
         ImageViewerCommon(dependencies)
     }
 }
 
-private fun getDependencies(context: Context, ioScope: CoroutineScope) = object : Dependencies() {
+private fun getDependencies(
+    context: Context,
+    ioScope: CoroutineScope,
+    externalEvents: Flow<ExternalImageViewerEvent>
+) = object : Dependencies() {
     override val notification: Notification = object : PopupNotification(localization) {
         override fun showPopUpMessage(text: String) {
             Toast.makeText(context, text, Toast.LENGTH_SHORT).show()
@@ -53,4 +66,5 @@ private fun getDependencies(context: Context, ioScope: CoroutineScope) = object
             }
         }
     }
+    override val externalEvents: Flow<ExternalImageViewerEvent> = externalEvents
 }

examples/imageviewer/shared/src/commonMain/kotlin/example/imageviewer/ImageViewer.common.kt

@@ -8,9 +8,9 @@ import example.imageviewer.model.*
 import example.imageviewer.view.*
 
 enum class ExternalImageViewerEvent {
-    Foward,
+    Next,
-    Back,
+    Previous,
-    Escape,
+    ReturnBack,
 }
 
 @Composable
@@ -38,7 +38,7 @@ internal fun ImageViewerWithProvidedDependencies(
     val externalEvents = LocalInternalEvents.current
     LaunchedEffect(Unit) {
         externalEvents.collect {
-            if (it == ExternalImageViewerEvent.Escape) {
+            if (it == ExternalImageViewerEvent.ReturnBack) {
                 navigationStack.back()
             }
         }

examples/imageviewer/shared/src/commonMain/kotlin/example/imageviewer/view/GalleryScreen.kt

@@ -57,8 +57,8 @@ internal fun GalleryScreen(
     LaunchedEffect(Unit) {
         externalEvents.collect {
             when (it) {
-                ExternalImageViewerEvent.Foward -> nextImage()
+                ExternalImageViewerEvent.Next -> nextImage()
-                ExternalImageViewerEvent.Back -> previousImage()
+                ExternalImageViewerEvent.Previous -> previousImage()
                 else -> {}
             }
         }

examples/imageviewer/shared/src/desktopMain/kotlin/example/imageviewer/view/ImageViewer.desktop.kt

@@ -24,7 +24,6 @@ import kotlinx.coroutines.channels.BufferOverflow
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
-import java.awt.Desktop
 import java.awt.Dimension
 import java.awt.Toolkit
 
@@ -63,15 +62,15 @@ fun ApplicationScope.ImageViewerDesktop() {
             if (it.type == KeyEventType.KeyUp) {
                 when (it.key) {
                     Key.DirectionLeft -> externalNavigationEventBus.produceEvent(
-                        ExternalImageViewerEvent.Back
+                        ExternalImageViewerEvent.Previous
                     )
 
                     Key.DirectionRight -> externalNavigationEventBus.produceEvent(
-                        ExternalImageViewerEvent.Foward
+                        ExternalImageViewerEvent.Next
                     )
 
                     Key.Escape -> externalNavigationEventBus.produceEvent(
-                        ExternalImageViewerEvent.Escape
+                        ExternalImageViewerEvent.ReturnBack
                     )
                 }
             }