我正在尝试更新服务中的音乐播放器 SeekBar，但没有任何反应。该服务在我的活动中启动正常并正确绑定（因为我可以使用我的服务中的一些方法并且音乐播放正常）。这是我的服务代码：
public class MusicPlayerService extends Service {
MediaPlayer myMusicPlayer;
String path;
Intent getMusicId = new Intent();
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
MusicPlayerService getService() {
// Return this instance of LocalService so clients can call public methods
return MusicPlayerService.this;
}
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
myMusicPlayer = new MediaPlayer();
Log.d(getClass().getSimpleName(),"onCreate()");
super.onCreate();
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
Log.d(getClass().getSimpleName(), "onStartCommand()");
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent intent) {
path = intent.getStringExtra("musicID");
Log.e("Music path on SD received from intent", path);
try {
myMusicPlayer.setDataSource(path);
myMusicPlayer.setLooping(true);
myMusicPlayer.prepare();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
myMusicPlayer.start();
Log.d(getClass().getSimpleName(), "onBind()");
return mBinder;
}
/** method for clients */
public int getMusicDuration() {
return myMusicPlayer.getDuration();
}
public int getMusicCurPos(){
return myMusicPlayer.getCurrentPosition();
}
public void pauseMusic(){
myMusicPlayer.pause();
Log.d(getClass().getSimpleName(), "pauseMusic()");
}
public void playMusic(){
myMusicPlayer.start();
Log.d(getClass().getSimpleName(), "start()");
}
public void stopMusic(){
myMusicPlayer.stop();
Log.d(getClass().getSimpleName(), "stop()");
}
public void seekToPos (int pos){
myMusicPlayer.seekTo(pos);
}
}
有趣的部分是，在将服务绑定到我的活动并运行它之后，服务的一些方法返回 null 值，例如getDuration()，其中一些可以找到onStart()和onDestroy()。
提前致谢。
更新：
在您的活动中，您必须检查服务是否绑定，因为它需要一段时间才能完成，然后使用它提供的公共方法，例如：
//Bound Music service and pass the music path
Intent musicIntent = new Intent(this, MusicPlayerService.class);
musicIntent.putExtra("musicID", path); //Put Extra data for music player to play the exact file
bindService(musicIntent, mConnection, Context.BIND_AUTO_CREATE); //Bound the Music player service
//Music Handler for methods
musicMethodsHandler = new Handler();
musicRun = new Runnable() {
@Override
public void run() {
if (mBound == true){ // Check if service bounded
if (musicTotTime == null){ // Put data in it one time
musicTotTime = myMusicPlayer.getMusicDuration();
Log.v("Music Duration of Player in thread", musicTotTime.toString());
seekBar.setMax(musicTotTime);
}
musicCurTime = myMusicPlayer.getMusicCurPos();
Log.v("Music Duration of Player in thread", musicCurTime.toString());
seekBar.setProgress(musicCurTime);
}else if(mBound == false){ // if service is not bounded log it
Log.v("Still waiting to bound", Boolean.toString(mBound));
}
musicMethodsHandler.postDelayed(this, 1000);
}
};
musicMethodsHandler.postDelayed(musicRun, 1000);
/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to LocalService, cast the IBinder and get LocalService instance
LocalBinder binder = (LocalBinder) service;
myMusicPlayer = binder.getService();
mBound = true;
}
@Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
请记住，onCreate()服务的方法是先运行一次。