在播放音频时恢复音频播放器应用程序时，SeekBar重置为0。在音频播放期间，SeekBar更新进度。但是，当恢复屏幕显示时，SeekBar从头开始，而没有指示玩家的当前位置。当您按暂停按钮，然后按播放按钮时，它将再次在当前位置播放。在updateProgress()方法中，存在long currentPosition = mLastPlaybackState.getPosition();，我认为这段代码在恢复时并未指示当前位置。
这是我的NowPlayingAcitivy.java：
private PlaybackStateCompat mLastPlaybackState;
private final Handler mHandler = new Handler();
private final Runnable mUpdateProgressTask = new Runnable() {
@Override
public void run() {
updateProgress();
}
};
private final ScheduledExecutorService mExecutorService =
Executors.newSingleThreadScheduledExecutor();
private ScheduledFuture<?> mScheduledFuture;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mNowPlayingBinding = DataBindingUtil.setContentView(
this, R.layout.activity_now_playing);
createMediaBrowserCompat();
mNowPlayingBinding.playingInfo.seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
mNowPlayingBinding.playingInfo.tvStart.setText(DateUtils.formatElapsedTime(
progress/1000));
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// Cancel the future returned by scheduleAtFixedRate() to stop the SeekBar from progressing
stopSeekbarUpdate();
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
MediaControllerCompat.getMediaController(NowPlayingActivity.this)
.getTransportControls().seekTo(seekBar.getProgress());
// Create and execute a periodic action to update the SeekBar progress
scheduleSeekbarUpdate();
}
});
}
private void createMediaBrowserCompat() {
mMediaBrowser = new MediaBrowserCompat(this,
new ComponentName(this, PodcastService.class),
mConnectionCallbacks,
null);
}
@Override
protected void onStart() {
super.onStart();
mMediaBrowser.connect();
}
@Override
protected void onResume() {
super.onResume();
setVolumeControlStream(AudioManager.STREAM_MUSIC);
}
@Override
protected void onStop() {
super.onStop();
if (MediaControllerCompat.getMediaController(this) != null) {
MediaControllerCompat.getMediaController(this).unregisterCallback(controllerCallback);
}
mMediaBrowser.disconnect();
}
@Override
protected void onDestroy() {
super.onDestroy();
stopSeekbarUpdate();
mExecutorService.shutdown();
}
private final MediaBrowserCompat.ConnectionCallback mConnectionCallbacks =
new MediaBrowserCompat.ConnectionCallback() {
@Override
public void onConnected() {
MediaSessionCompat.Token token = mMediaBrowser.getSessionToken();
MediaControllerCompat mediaController = null;
try {
mediaController = new MediaControllerCompat(NowPlayingActivity.this, token);
} catch (RemoteException e) {
Timber.e("Error creating media controller");
}
MediaControllerCompat.setMediaController(NowPlayingActivity.this,
mediaController);
buildTransportControls();
}
@Override
public void onConnectionSuspended() {
super.onConnectionSuspended();
}
@Override
public void onConnectionFailed() {
super.onConnectionFailed();
}
};
void buildTransportControls() {
mNowPlayingBinding.playingInfo.ibPlayPause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
PlaybackStateCompat pbState =
MediaControllerCompat.getMediaController(NowPlayingActivity.this).getPlaybackState();
if (pbState != null) {
MediaControllerCompat.TransportControls controls =
MediaControllerCompat.getMediaController(NowPlayingActivity.this).getTransportControls();
switch (pbState.getState()) {
case PlaybackStateCompat.STATE_PLAYING: // fall through
case PlaybackStateCompat.STATE_BUFFERING:
controls.pause();
stopSeekbarUpdate();
break;
case PlaybackStateCompat.STATE_PAUSED:
case PlaybackStateCompat.STATE_STOPPED:
controls.play();
scheduleSeekbarUpdate();
break;
default:
Timber.d("onClick with state " + pbState);
}
}
}
});
MediaControllerCompat mediaController =
MediaControllerCompat.getMediaController(NowPlayingActivity.this);
MediaMetadataCompat metadata = mediaController.getMetadata();
PlaybackStateCompat pbState = mediaController.getPlaybackState();
updatePlaybackState(pbState);
if (metadata != null) {
// Get the episode duration from the metadata and sets the end time to the textView
updateDuration(metadata);
}
// Set the current progress to the current position
updateProgress();
if (pbState != null && (pbState.getState() == PlaybackStateCompat.STATE_PLAYING ||
pbState.getState() == PlaybackStateCompat.STATE_BUFFERING)) {
scheduleSeekbarUpdate();
}
mediaController.registerCallback(controllerCallback);
}
MediaControllerCompat.Callback controllerCallback = new MediaControllerCompat.Callback() {
@Override
public void onMetadataChanged(MediaMetadataCompat metadata) {
super.onMetadataChanged(metadata);
if (metadata != null) {
updateDuration(metadata);
}
}
@Override
public void onPlaybackStateChanged(PlaybackStateCompat state) {
super.onPlaybackStateChanged(state);
// Update the playback state
updatePlaybackState(state);
}
};
/**
* Creates and executes a periodic action that becomes enabled first after the given initial delay,
* and subsequently with the given period;that is executions will commence after initialDelay
* then initialDelay + period, then initialDelay + 2 * period, and so on.
*/
private void scheduleSeekbarUpdate() {
stopSeekbarUpdate();
if (!mExecutorService.isShutdown()) {
mScheduleFuture = mExecutorService.scheduleAtFixedRate(
new Runnable() {
@Override
public void run() {
mHandler.post(mUpdateProgressTask);
}
}, 100,
1000, TimeUnit.MILLISECONDS);
}
}
/**
* Cancels the future returned by scheduleAtFixedRate() to stop the SeekBar from progressing.
*/
private void stopSeekbarUpdate() {
if (mScheduledFuture != null) {
mScheduledFuture.cancel(false);
}
}
/**
* Gets the episode duration from the metadata and sets the end time to be displayed in the TextView.
*/
private void updateDuration(MediaMetadataCompat metadata) {
if (metadata == null) {
return;
}
int duration = (int) metadata.getLong(MediaMetadataCompat.METADATA_KEY_DURATION)
* 1000;
mNowPlayingBinding.playingInfo.seekBar.setMax(duration);
mNowPlayingBinding.playingInfo.tvEnd.setText(
DateUtils.formatElapsedTime(duration / 1000));
}
/**
* Calculates the current position (distance = timeDelta * velocity) and sets the current progress
* to the current position.
*/
private void updateProgress() {
if (mLastPlaybackState == null) {
return;
}
long currentPosition = mLastPlaybackState.getPosition();
if (mLastPlaybackState.getState() == PlaybackStateCompat.STATE_PLAYING) {
// Calculate the elapsed time between the last position update and now and unless
// paused, we can assume (delta * speed) + current position is approximately the
// latest position. This ensure that we do not repeatedly call the getPlaybackState()
// on MediaControllerCompat.
long timeDelta = SystemClock.elapsedRealtime() -
mLastPlaybackState.getLastPositionUpdateTime();
currentPosition += (int) timeDelta * mLastPlaybackState.getPlaybackSpeed();
}
mNowPlayingBinding.playingInfo.seekBar.setProgress((int) currentPosition);
}
private void updatePlaybackState(PlaybackStateCompat state) {
if (state == null) {
return;
}
mLastPlaybackState = state;
switch (state.getState()) {
case PlaybackStateCompat.STATE_PLAYING:
hideLoading();
mNowPlayingBinding.playingInfo.ibPlayPause.setImageResource(R.drawable.exo_controls_pause);
scheduleSeekbarUpdate();
break;
case PlaybackStateCompat.STATE_PAUSED:
hideLoading();
mNowPlayingBinding.playingInfo.ibPlayPause.setImageResource(R.drawable.exo_controls_play);
stopSeekbarUpdate();
break;
case PlaybackStateCompat.STATE_NONE:
case PlaybackStateCompat.STATE_STOPPED:
hideLoading();
mNowPlayingBinding.playingInfo.ibPlayPause.setImageResource(R.drawable.exo_controls_play);
stopSeekbarUpdate();
break;
case PlaybackStateCompat.STATE_BUFFERING:
showLoading();
mNowPlayingBinding.playingInfo.ibPlayPause.setImageResource(R.drawable.exo_controls_play);
stopSeekbarUpdate();
break;
default:
Timber.d("Unhandled state " + state.getState());
}
}
这是我的PodcastService.java：
public class PodcastService extends MediaBrowserServiceCompat implements Player.EventListener {
@Override
public void onCreate() {
super.onCreate();
initializeMediaSession();
}
private void initializeMediaSession() {
mMediaSession = new MediaSessionCompat(PodcastService.this, TAG);
mMediaSession.setFlags(
MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS |
MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS);
mStateBuilder = new PlaybackStateCompat.Builder()
.setActions(
PlaybackStateCompat.ACTION_PLAY |
PlaybackStateCompat.ACTION_PAUSE |
PlaybackStateCompat.ACTION_REWIND |
PlaybackStateCompat.ACTION_FAST_FORWARD |
PlaybackStateCompat.ACTION_PLAY_PAUSE);
mMediaSession.setPlaybackState(mStateBuilder.build());
mMediaSession.setCallback(new MySessionCallback());
setSessionToken(mMediaSession.getSessionToken());
mMediaSession.setSessionActivity(PendingIntent.getActivity(this,
11,
new Intent(this, NowPlayingActivity.class),
PendingIntent.FLAG_UPDATE_CURRENT));
}
private void initializePlayer() {
if (mExoPlayer == null) {
DefaultRenderersFactory defaultRenderersFactory = new DefaultRenderersFactory(this);
TrackSelector trackSelector = new DefaultTrackSelector();
LoadControl loadControl = new DefaultLoadControl();
mExoPlayer = ExoPlayerFactory.newSimpleInstance(this, defaultRenderersFactory,
trackSelector, loadControl);
mExoPlayer.addListener(this);
// Prepare the MediaSource
Uri mediaUri = Uri.parse(mUrl);
MediaSource mediaSource = buildMediaSource(mediaUri);
mExoPlayer.prepare(mediaSource);
mExoPlayer.setPlayWhenReady(true);
}
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if (intent == null || intent.getAction() == null) {
Timber.e("intent in onStartCommand is null");
return START_STICKY;
}
// Check if the old player should be released
if (intent.getAction() != null && intent.getAction().equals(ACTION_RELEASE_OLD_PLAYER)) {
if (mExoPlayer != null) {
mExoPlayer.stop();
releasePlayer();
}
}
Bundle b = intent.getBundleExtra(EXTRA_ITEM);
if (b != null) {
mItem = b.getParcelable(EXTRA_ITEM);
mUrl = mItem.getEnclosures().get(0).getUrl();
}
initializePlayer();
// Convert hh:mm:ss string to seconds to put it into the metadata
long duration = PodUtils.getDurationInMilliSeconds(mItem);
MediaMetadataCompat metadata = new MediaMetadataCompat.Builder()
.putLong(MediaMetadataCompat.METADATA_KEY_DURATION, duration).build();
mMediaSession.setMetadata(metadata);
return START_STICKY;
}
private void releasePlayer() {
mExoPlayer.release();
mExoPlayer = null;
}
@Override
public void onTaskRemoved(Intent rootIntent) {
super.onTaskRemoved(rootIntent);
if (mExoPlayer != null) {
mExoPlayer.stop(true);
}
stopSelf();
}
@Override
public void onDestroy() {
mMediaSession.release();
releasePlayer();
super.onDestroy();
}
private MediaSource buildMediaSource(Uri mediaUri) {
String userAgent = Util.getUserAgent(this, getString(R.string.app_name));
DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(
this, userAgent);
CacheDataSourceFactory cacheDataSourceFactory =
new CacheDataSourceFactory(
DownloadUtil.getCache(this),
dataSourceFactory,
CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR);
return new ExtractorMediaSource.Factory(cacheDataSourceFactory).createMediaSource(mediaUri);
}
@Nullable
@Override
public BrowserRoot onGetRoot(@NonNull String clientPackageName, int clientUid,
@Nullable Bundle rootHints) {
return new BrowserRoot("pod_root_id", null);
}
@Override
public void onLoadChildren(@NonNull String parentMediaId,
@NonNull Result<List<MediaBrowserCompat.MediaItem>> result) {
// Browsing not allowed
if (TextUtils.equals("empty_root_id", parentMediaId)) {
result.sendResult(null);
return;
}
List<MediaBrowserCompat.MediaItem> mediaItems = new ArrayList<>();
// Check if this is the root menu:
if ("pod_root_id".equals(parentMediaId)) {
// Build the MediaItem objects for the top level,
// and put them in the mediaItems list...
} else {
// Examine the passed parentMediaId to see which submenu we're at,
// and put the children of that menu in the mediaItems list...
}
result.sendResult(mediaItems);
}
private class MySessionCallback extends MediaSessionCompat.Callback {
@Override
public void onPlay() {
startService(new Intent(getApplicationContext(), PodcastService.class));
mMediaSession.setActive(true);
// Start the player
if (mExoPlayer != null) {
mExoPlayer.setPlayWhenReady(true);
}
}
@Override
public void onPause() {
mExoPlayer.setPlayWhenReady(false);
stopForeground(false);
}
@Override
public void onRewind() {
mExoPlayer.seekTo(Math.max(mExoPlayer.getCurrentPosition() - 10000, 0));
}
@Override
public void onFastForward() {
long duration = mExoPlayer.getDuration();
mExoPlayer.seekTo(Math.min(mExoPlayer.getCurrentPosition() + 30000, duration));
}
@Override
public void onStop() {
stopSelf();
mMediaSession.setActive(false);
mExoPlayer.stop();
stopForeground(true);
}
@Override
public void onSeekTo(long pos) {
super.onSeekTo(pos);
if (mExoPlayer != null) {
mExoPlayer.seekTo((int) pos);
}
}
}
// Player Event Listeners
@Override
public void onTimelineChanged(Timeline timeline, @Nullable Object manifest, int reason) {
}
@Override
public void onPlayerError(ExoPlaybackException error) {
}
@Override
public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
if (playbackState == Player.STATE_IDLE) {
mStateBuilder.setState(PlaybackStateCompat.STATE_PAUSED,
mExoPlayer.getCurrentPosition(), 1f);
} else if (playbackState == Player.STATE_BUFFERING) {
mStateBuilder.setState(PlaybackStateCompat.STATE_BUFFERING,
mExoPlayer.getCurrentPosition(), 1f);
} else if (playbackState == Player.STATE_READY && playWhenReady) {
mStateBuilder.setState(PlaybackStateCompat.STATE_PLAYING,
mExoPlayer.getCurrentPosition(), 1f);
Timber.d("onPlayerStateChanged: we are playing");
} else if (playbackState == Player.STATE_READY) {
mStateBuilder.setState(PlaybackStateCompat.STATE_PAUSED,
mExoPlayer.getCurrentPosition(), 1f);
Timber.d("onPlayerStateChanged: we are paused");
} else if (playbackState == Player.STATE_ENDED) {
mStateBuilder.setState(PlaybackStateCompat.STATE_PAUSED,
mExoPlayer.getCurrentPosition(), 1f);
} else {
mStateBuilder.setState(PlaybackStateCompat.STATE_NONE,
mExoPlayer.getCurrentPosition(), 1f);
}
mMediaSession.setPlaybackState(mStateBuilder.build());
}
}
编辑：完整的源代码可用here。
答案 0 :(得分：0)
要基于值设置状态进度，请使用setProgress(value)方法。
当暂停来自seekBar的音乐保存值作为Integer时，然后在恢复它时获得该值并将其作为参数放入setProgress()方法中。
当您暂停音乐以保存值时：
@Override
protected void onPause() {
super.onPause();
mSeekBarRate.setOnSeekBarChangeListener(
new SeekBar.OnSeekBarChangeListener() {
int progress = 0;
@Override
public void onProgressChanged(SeekBar mSeekBarRate, int progressValue, boolean fromUser) {
progress = progressValue;
}
@Override
public void onStartTrackingTouch(SeekBar mSeekBarRate) {
}
@Override
public void onStopTrackingTouch(SeekBar mSeekBarRate) {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
SharedPreferences.Editor editor = prefs.edit();
editor.putInt("value", progress);
}
});
}
当您恢复音乐时，将获取该值：
@Override
protected void onStart() {
super.onStart();
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
int value = prefs.getInt("value", 0);
mSeekBarRate.setProgress(value);
}
希望它对您有帮助。