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[英]Calling BroadCastReceiver from Service in android to Update UI in Fragment?
[英]How to update android fragment UI from service?
我正在開發一個可播放實時廣播音頻流的android應用程序。 我已經為此實現了android MediaPlayer API,該API不斷從遠程源接收音頻數據。
在單擊“播放”按鈕上,我啟動了一個服務並從那里控制MediaPlayer實例。 我成功完成了所有工作,我的工作代碼如下:
ListenFragment.java
playbtn_flat.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
// TODO Auto-generated method stub
if(isNetworkConnected())
{
serviceIntent.putExtra("sentAudioLink",strAudioLink);
try
{
getActivity().startService(new Intent(getContext(),PlayService.class));
}
catch (Exception e)
{
Toast.makeText(getContext(),e.getClass().getName()+" "+e.getMessage(),Toast.LENGTH_SHORT).show();
}
}
}
});
PlayService.java:
public class PlayService extends Service implements MediaPlayer.OnCompletionListener,MediaPlayer.OnPreparedListener,
MediaPlayer.OnErrorListener,MediaPlayer.OnSeekCompleteListener,MediaPlayer.OnInfoListener,
MediaPlayer.OnBufferingUpdateListener {
private MediaPlayer mediaPlayer = new MediaPlayer();
private String sentAudioLink;
@Override
public void onCreate() {
mediaPlayer.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
mediaPlayer.setOnCompletionListener(this);
mediaPlayer.setOnPreparedListener(this);
mediaPlayer.setOnErrorListener(this);
mediaPlayer.setOnSeekCompleteListener(this);
mediaPlayer.setOnInfoListener(this);
mediaPlayer.setOnBufferingUpdateListener(this);
mediaPlayer.reset();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
sentAudioLink = intent.getExtras().getString("sentAudioLink");
mediaPlayer.reset();
//setup the media player data source using the strAudioLink value
if (!mediaPlayer.isPlaying()) {
try {
mediaPlayer.setDataSource(sentAudioLink);
//prepare media player
mediaPlayer.prepareAsync();
} catch (IllegalStateException e) {
Log.e("workingerror1", e.toString());
} catch (IllegalArgumentException e) {
Log.e("workingerror2", e.toString());
} catch (IOException e) {
Log.e("workingerror3", e.toString());
}
}
return START_STICKY;
}
@Override
public void onDestroy() {
super.onDestroy();
if (mediaPlayer != null && mediaPlayer.isPlaying()) {
mediaPlayer.stop();
}
mediaPlayer.release();
}
@Override
public void onBufferingUpdate(MediaPlayer mp, int percent) {
}
@Override
public void onCompletion(MediaPlayer mp) {
stopMedia();
stopSelf();
}
public void stopMedia() {
if (mediaPlayer.isPlaying())
mediaPlayer.stop();
}
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
Toast.makeText(this, "Error" + what, Toast.LENGTH_LONG).show();
Log.e("workingmain_error", "error");
Log.e("workingmain_error2", String.format("Error(%s%s)", what, extra));
return false;
}
@Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
return false;
}
@Override
public void onPrepared(MediaPlayer mp) {
playMedia();
}
public void playMedia() {
if (!mediaPlayer.isPlaying()) {
Log.e("working4", "error");
mediaPlayer.start();
}
}
@Override
public void onSeekComplete(MediaPlayer mp) {
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
我面對的唯一問題是,我想在UI的TextView文本從“ 聽現場 ”改變“ 載入中...”,再到“ 直播 ”為媒體播放器啟動。
您可以為此使用廣播接收器。 在您的服務中發送廣播,並且可以在片段中注冊以收聽該廣播,並根據該廣播更改UI。
例如,使用
Intent intent = new Intent("intent_filter");
intent.putString("messageToShow","On Air");
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
localBroadcastManager.sendBroadcast(intent);
並在您的片段中使用:
LocalBroadcastManager.getInstance(this).registerReceiver(new YourReceiver(),new IntentFilter("intent_filter"));
您可以在https://developer.android.com/reference/android/support/v4/content/LocalBroadcastManager上閱讀更多內容
您還可以查看EventBus。
一種可能的解決方案是使用綁定服務https://developer.android.com/guide/components/bound-services引用IBinder實例,並讓您與服務進行通信。 通信(從服務到片段)可以通過提供偵聽器對象(例如IPlayServiceListener
)來完成。
這是您的服務的樣子:
public class PlayService extends Service implements MediaPlayer.OnCompletionListener,MediaPlayer.OnPreparedListener,
MediaPlayer.OnErrorListener,MediaPlayer.OnSeekCompleteListener,MediaPlayer.OnInfoListener,
MediaPlayer.OnBufferingUpdateListener {
private final IBinder mBinder = new PlayServiceLocalBinder();
private IPlayServiceListener listener = null;
/** Binder allowing external components to interact with the service */
public class PlayServiceLocalBinder extends Binder {
public PlayService getService() {
// Return this instance of LocalService so clients can call public methods
return PlayService.this;
}
}
public void setListener(IPlayServiceListener listener) {
this.listener = listener;
}
....
@Nullable
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
}
然后為了啟動服務:
Intent intent = new Intent(getContext(), PlayService.class);
bindService(intent, mPlayServiceConnection, Context.BIND_AUTO_CREATE));
private final ServiceConnection mPlayServiceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName className, IBinder service) {
PlayService.PlayServiceLocalBinder binder = (PlayService.PlayServiceLocalBinder) service;
mPlayService = binder.getService();
mPlayService.setListener(YourFragment.this);
}
@Override
public void onServiceDisconnected(ComponentName className) {
}
};
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