[Android] Add support for android auto to start on a random track when shuffle is enabled

[Robert Stone]

vlc-android | branch: master | Robert Stone <rhstone at gmail.com> | Tue Jul 27 21:43:27 2021 -0700| [a256140975121eb5122243fcfc0920ed8c50023f] | committer: Nicolas Pomepuy

Add support for android auto to start on a random track when shuffle is enabled

> https://code.videolan.org/videolan/vlc-android/commit/a256140975121eb5122243fcfc0920ed8c50023f
---

 .../vlc-android/src/org/videolan/vlc/MediaSessionCallback.kt  | 11 ++++++-----
 .../vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt |  6 +++---
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/application/vlc-android/src/org/videolan/vlc/MediaSessionCallback.kt b/application/vlc-android/src/org/videolan/vlc/MediaSessionCallback.kt
index 5ed8bfc75..c397995de 100644
--- a/application/vlc-android/src/org/videolan/vlc/MediaSessionCallback.kt
+++ b/application/vlc-android/src/org/videolan/vlc/MediaSessionCallback.kt
@@ -188,15 +188,15 @@ internal class MediaSessionCallback(private val playbackService: PlaybackService
                                 }
                                 MediaSessionBrowser.ID_ARTIST -> {
                                     val tracks = context.getFromMl { getArtist(id)?.tracks }
-                                    if (isActive) tracks?.let { loadMedia(it.toList()) }
+                                    if (isActive) tracks?.let { loadMedia(it.toList(), allowRandom = true) }
                                 }
                                 MediaSessionBrowser.ID_GENRE -> {
                                     val tracks = context.getFromMl { getGenre(id)?.albums?.flatMap { it.tracks.toList() } }
-                                    if (isActive) tracks?.let { loadMedia(it.toList()) }
+                                    if (isActive) tracks?.let { loadMedia(it.toList(), allowRandom = true) }
                                 }
                                 MediaSessionBrowser.ID_PLAYLIST -> {
                                     val tracks = context.getFromMl { getPlaylist(id, Settings.includeMissing)?.tracks }
-                                    if (isActive) tracks?.let { loadMedia(it.toList()) }
+                                    if (isActive) tracks?.let { loadMedia(it.toList(), allowRandom = true) }
                                 }
                                 MediaSessionBrowser.ID_MEDIA -> {
                                     val tracks = context.getFromMl { getMedia(id)?.tracks }
@@ -217,11 +217,12 @@ internal class MediaSessionCallback(private val playbackService: PlaybackService
         }
     }
 
-    private fun loadMedia(mediaList: List<MediaWrapper>?, position: Int = 0) {
+    private fun loadMedia(mediaList: List<MediaWrapper>?, position: Int = 0, allowRandom: Boolean = false) {
         mediaList?.let { mediaList ->
             if (AndroidDevices.isCarMode(playbackService.applicationContext))
                 mediaList.forEach { if (it.type == MediaWrapper.TYPE_VIDEO) it.addFlags(MediaWrapper.MEDIA_FORCE_AUDIO) }
-            playbackService.load(mediaList, position)
+            // Pick a random first track if allowRandom is true and shuffle is enabled
+            playbackService.load(mediaList, if (allowRandom && playbackService.isShuffling) SecureRandom().nextInt(min(mediaList.size, MEDIALIBRARY_PAGE_SIZE)) else position)
         }
     }
 
diff --git a/application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt b/application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt
index a5b8531e2..943e3e14c 100644
--- a/application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt
+++ b/application/vlc-android/src/org/videolan/vlc/media/PlaylistManager.kt
@@ -280,10 +280,10 @@ class PlaylistManager(val service: PlaybackService) : MediaWrapperList.EventList
     }
 
     @MainThread
-    fun previous(force : Boolean) {
+    fun previous(force: Boolean) {
         mediaList.getMedia(currentIndex)?.let { if (it.type == MediaWrapper.TYPE_VIDEO) it.time = player.getCurrentTime() }
-        if (hasPrevious() && currentIndex > 0 &&
-                ((force || !player.seekable || (player.getCurrentTime() < PREVIOUS_LIMIT_DELAY) || (lastPrevious != -1L && System.currentTimeMillis() - lastPrevious <  PREVIOUS_LIMIT_DELAY)))) {
+        if (hasPrevious() &&
+                ((force || !player.seekable || (player.getCurrentTime() < PREVIOUS_LIMIT_DELAY) || (lastPrevious != -1L && System.currentTimeMillis() - lastPrevious < PREVIOUS_LIMIT_DELAY)))) {
             val size = mediaList.size()
             currentIndex = prevIndex
             if (previous.size > 0) previous.pop()