Background file viewer playlist creation

app/src/main/java/sushi/hardcore/droidfs/file_viewers/FileViewerActivity.kt

@@ -14,6 +14,8 @@ import androidx.lifecycle.lifecycleScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
 import sushi.hardcore.droidfs.BaseActivity
 import sushi.hardcore.droidfs.FileTypes
@@ -21,7 +23,6 @@ import sushi.hardcore.droidfs.R
 import sushi.hardcore.droidfs.VolumeManagerApp
 import sushi.hardcore.droidfs.explorers.ExplorerElement
 import sushi.hardcore.droidfs.filesystems.EncryptedVolume
-import sushi.hardcore.droidfs.util.IntentUtils
 import sushi.hardcore.droidfs.util.PathUtils
 import sushi.hardcore.droidfs.util.finishOnClose
 import sushi.hardcore.droidfs.widgets.CustomAlertDialogBuilder
@@ -32,9 +33,8 @@ abstract class FileViewerActivity: BaseActivity() {
     private lateinit var originalParentPath: String
     private lateinit var windowInsetsController: WindowInsetsControllerCompat
     private var windowTypeMask = 0
-    private var foldersFirst = true
-    private var wasMapped = false
-    protected val mappedPlaylist = mutableListOf<ExplorerElement>()
+    protected val playlist = mutableListOf<ExplorerElement>()
+    private val playlistMutex = Mutex()
     protected var currentPlaylistIndex = -1
     private val isLegacyFullscreen = Build.VERSION.SDK_INT <= Build.VERSION_CODES.R
 
@@ -46,7 +46,6 @@ abstract class FileViewerActivity: BaseActivity() {
             intent.getIntExtra("volumeId", -1)
         )!!
         finishOnClose(encryptedVolume)
-        foldersFirst = sharedPrefs.getBoolean("folders_first", true)
         windowInsetsController = WindowInsetsControllerCompat(window, window.decorView)
         windowInsetsController.addOnControllableInsetsChangedListener { _, typeMask ->
             windowTypeMask = typeMask
@@ -131,48 +130,53 @@ abstract class FileViewerActivity: BaseActivity() {
         }
     }
 
-    protected fun createPlaylist() {
-        if (!wasMapped){
-            encryptedVolume.recursiveMapFiles(originalParentPath)?.let { elements ->
-                for (e in elements) {
-                    if (e.isRegularFile) {
-                        if (FileTypes.isExtensionType(getFileType(), e.name) || filePath == e.fullPath) {
-                            mappedPlaylist.add(e)
-                        }
-                    }
+    protected suspend fun createPlaylist() {
+        playlistMutex.withLock {
+            if (currentPlaylistIndex != -1) {
+                // playlist already initialized
+                return
             }
+            withContext(Dispatchers.IO) {
+                encryptedVolume.recursiveMapFiles(originalParentPath)?.filterTo(playlist) { e ->
+                    e.isRegularFile && (FileTypes.isExtensionType(getFileType(), e.name) || filePath == e.fullPath)
                 }
                 val sortOrder = intent.getStringExtra("sortOrder") ?: "name"
-            ExplorerElement.sortBy(sortOrder, foldersFirst, mappedPlaylist)
-            //find current index
-            for ((i, e) in mappedPlaylist.withIndex()){
-                if (filePath == e.fullPath){
-                    currentPlaylistIndex = i
-                    break
+                val foldersFirst = sharedPrefs.getBoolean("folders_first", true)
+                ExplorerElement.sortBy(sortOrder, foldersFirst, playlist)
+                currentPlaylistIndex = playlist.indexOfFirst { it.fullPath == filePath }
             }
         }
-            wasMapped = true
-        }
     }
 
-    protected fun playlistNext(forward: Boolean) {
+    private fun updateCurrentItem() {
+        filePath = playlist[currentPlaylistIndex].fullPath
+    }
+
+    protected suspend fun playlistNext(forward: Boolean) {
         createPlaylist()
         currentPlaylistIndex = if (forward) {
-            (currentPlaylistIndex+1)%mappedPlaylist.size
+            (currentPlaylistIndex + 1).mod(playlist.size)
         } else {
-            var x = (currentPlaylistIndex-1)%mappedPlaylist.size
-            if (x < 0) {
-                x += mappedPlaylist.size
+            (currentPlaylistIndex - 1).mod(playlist.size)
         }
-            x
-        }
-        filePath = mappedPlaylist[currentPlaylistIndex].fullPath
+        updateCurrentItem()
     }
 
-    protected fun refreshPlaylist() {
-        mappedPlaylist.clear()
-        wasMapped = false
-        createPlaylist()
+    protected suspend fun deleteCurrentFile(): Boolean {
+        createPlaylist() // ensure we know the current position in the playlist
+        return if (encryptedVolume.deleteFile(filePath)) {
+            playlist.removeAt(currentPlaylistIndex)
+            if (playlist.size != 0) {
+                if (currentPlaylistIndex == playlist.size) {
+                    // deleted the last element of the playlist, go back to the first
+                    currentPlaylistIndex = 0
+                }
+                updateCurrentItem()
+            }
+            true
+        } else {
+            false
+        }
     }
 
     protected fun goBackToExplorer() {

app/src/main/java/sushi/hardcore/droidfs/file_viewers/ImageViewer.kt

@@ -12,10 +12,12 @@ import android.widget.Toast
 import androidx.activity.addCallback
 import androidx.activity.viewModels
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.lifecycleScope
 import com.bumptech.glide.Glide
 import com.bumptech.glide.RequestBuilder
 import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool
 import com.bumptech.glide.load.resource.bitmap.BitmapTransformation
+import kotlinx.coroutines.launch
 import sushi.hardcore.droidfs.Constants
 import sushi.hardcore.droidfs.R
 import sushi.hardcore.droidfs.databinding.ActivityImageViewerBinding
@@ -105,17 +107,15 @@ class ImageViewer: FileViewerActivity() {
                 .keepFullScreen()
                 .setTitle(R.string.warning)
                 .setPositiveButton(R.string.ok) { _, _ ->
-                    createPlaylist() //be sure the playlist is created before deleting if there is only one image
-                    if (encryptedVolume.deleteFile(filePath)) {
-                        playlistNext(true)
-                        refreshPlaylist()
-                        if (mappedPlaylist.size == 0) { //deleted all images of the playlist
+                    lifecycleScope.launch {
+                        if (deleteCurrentFile()) {
+                            if (playlist.size == 0) { // no more image left
                                 goBackToExplorer()
                             } else {
                                 loadImage(true)
                             }
                         } else {
-                        CustomAlertDialogBuilder(this, theme)
+                            CustomAlertDialogBuilder(this@ImageViewer, theme)
                                 .keepFullScreen()
                                 .setTitle(R.string.error)
                                 .setMessage(getString(R.string.remove_failed, fileName))
@@ -123,6 +123,7 @@ class ImageViewer: FileViewerActivity() {
                                 .show()
                         }
                     }
+                }
                 .setNegativeButton(R.string.cancel, null)
                 .setMessage(getString(R.string.single_delete_confirm, fileName))
                 .show()
@@ -199,6 +200,7 @@ class ImageViewer: FileViewerActivity() {
     }
 
     private fun swipeImage(deltaX: Float, slideshowSwipe: Boolean = false) {
+        lifecycleScope.launch {
             playlistNext(deltaX < 0)
             loadImage(true)
             if (slideshowActive) {
@@ -208,6 +210,7 @@ class ImageViewer: FileViewerActivity() {
                 handler.postDelayed(slideshowNext, Constants.SLIDESHOW_DELAY)
             }
         }
+    }
 
     private fun stopSlideshow(){
         slideshowActive = false

app/src/main/java/sushi/hardcore/droidfs/file_viewers/MediaPlayer.kt

@@ -2,6 +2,7 @@ package sushi.hardcore.droidfs.file_viewers
 
 import android.view.WindowManager
 import androidx.annotation.OptIn
+import androidx.lifecycle.lifecycleScope
 import androidx.media3.common.MediaItem
 import androidx.media3.common.PlaybackException
 import androidx.media3.common.Player
@@ -11,6 +12,7 @@ import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.exoplayer.source.MediaSource
 import androidx.media3.exoplayer.source.ProgressiveMediaSource
 import androidx.media3.extractor.DefaultExtractorsFactory
+import kotlinx.coroutines.launch
 import sushi.hardcore.droidfs.Constants
 import sushi.hardcore.droidfs.R
 import sushi.hardcore.droidfs.widgets.CustomAlertDialogBuilder
@@ -39,12 +41,16 @@ abstract class MediaPlayer: FileViewerActivity() {
     private fun initializePlayer(){
         player = ExoPlayer.Builder(this).setSeekForwardIncrementMs(5000).build()
         bindPlayer(player)
+        player.addMediaSource(createMediaSource(filePath))
+        lifecycleScope.launch {
             createPlaylist()
-        for (e in mappedPlaylist) {
-            player.addMediaSource(createMediaSource(e.fullPath))
+            playlist.forEachIndexed { index, e ->
+                if (index != currentPlaylistIndex) {
+                    player.addMediaSource(index, createMediaSource(e.fullPath))
+                }
+            }
         }
         player.repeatMode = Player.REPEAT_MODE_ALL
-        player.seekToDefaultPosition(currentPlaylistIndex)
         player.playWhenReady = true
         player.addListener(object : Player.Listener{
             override fun onVideoSizeChanged(videoSize: VideoSize) {
@@ -67,11 +73,13 @@ abstract class MediaPlayer: FileViewerActivity() {
             }
 
             override fun onMediaItemTransition(mediaItem: MediaItem?, reason: Int) {
-                if (player.repeatMode != Player.REPEAT_MODE_ONE) {
-                    playlistNext(player.currentMediaItemIndex == (currentPlaylistIndex + 1) % mappedPlaylist.size)
+                if (player.repeatMode != Player.REPEAT_MODE_ONE && currentPlaylistIndex != -1) {
+                    lifecycleScope.launch {
+                        playlistNext(player.currentMediaItemIndex == (currentPlaylistIndex + 1) % player.mediaItemCount)
                         refreshFileName()
                     }
                 }
+            }
         })
         player.prepare()
     }