Java MediaController-调用Show（）时出错
我有这段代码用于显示MediaController，但是当我调用show（）方法时，它给了我一个致命的错误 MediaPlayer本身正在处理服务，并从MediaPlayerControl界面获取意图 我的代码：Java MediaController-调用Show（）时出错,java,android,android-mediaplayer,mediacontroller,Java,Android,Android Mediaplayer,Mediacontroller,我有这段代码用于显示MediaController，但是当我调用show（）方法时，它给了我一个致命的错误 MediaPlayer本身正在处理服务，并从MediaPlayerControl界面获取意图 我的代码： @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mediaController = new MediaController(this, false);
mediaController.setMediaPlayer(mediaPlayerControl);
mediaController.setAnchorView(findViewById(R.id.mediaController));
mediaController.setEnabled(true);
mediaController.show(0);
}
//implements MediaPlayerControl interface
private MediaPlayerControl mediaPlayerControl = new MediaPlayerControl()
{
//Override the methods to send Intent to the MediaPlayer Service
....
....
};
我的代码有什么问题？好的，我很好地找到了答案。 问题在于：
mediaController.show(0);
onCreate（）mediaController.show（0）的底部当它点击时，应用程序工作正常
所以现在我必须在应用程序激活后拨打这条电话。
我尝试了onStart（）和onResume（），但都不起作用。同样的错误logCat
我怎样才能解决这个问题 我遇到了同样的问题，几个小时后得到了解决方案。我做了以下工作：
摘要：
public class MainActivity extends Activity implements MediaPlayer.OnPreparedListener, MediaController.MediaPlayerControl {
private static final String TAG = "AudioPlayer";
private MediaPlayer mediaPlayer;
private MediaController mediaController;
private Handler handler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
protected void onStart() {
Log.d(TAG, "Play - onStart");
super.onStart();
mediaPlayer = new MediaPlayer();
mediaController = new MediaController(this);
mediaPlayer.setOnPreparedListener(this);
try {
AssetFileDescriptor afd = getApplicationContext().getResources().openRawResourceFd(R.raw.audio_example);
mediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getDeclaredLength());
mediaPlayer.prepare();
afd.close();
} catch (IOException e) {
Log.e(TAG, "Error opening audio: " + e.getCause());
}
}
// override this method because of the OnPreparedListener interface
@Override
public void onPrepared(MediaPlayer mediaPlayer) {
Log.d(TAG, "Play - onPrepared");
mediaController.setMediaPlayer(this);
mediaController.setAnchorView(findViewById(R.id.mediaController1));
mediaPlayer.start();
handler.post(new Runnable() {
@Override
public void run() {
mediaController.setEnabled(true);
mediaController.show(0);
}
});
}
// override these methods because of the MediaController.MediaPlayerControl interface
@Override
public boolean canPause() {
return true;
}
@Override
public boolean canSeekBackward() {
return true;
}
@Override
public boolean canSeekForward() {
return true;
}
@Override
public int getAudioSessionId() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int getBufferPercentage() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int getCurrentPosition() {
return mediaPlayer.getCurrentPosition();
}
@Override
public int getDuration() {
return mediaPlayer.getDuration();
}
@Override
public boolean isPlaying() {
return mediaPlayer.isPlaying();
}
@Override
public void pause() {
mediaPlayer.pause();
}
@Override
public void seekTo(int pos) {
mediaPlayer.seekTo(pos);
}
@Override
public void start() {
mediaPlayer.start();
}
// release resources before kill the Activity
@Override
protected void onStop() {
Log.d(TAG, "Play - onStop");
super.onStop();
if (mediaPlayer != null) {
mediaController.hide();
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
}
} }
Activity类实现以下接口：MediaPlayer.OnPreparedListener和MediaController.MediaPlayerControl
- 一次创建。setContentView
- 开始。创建MediaPlayer和MediaController，使用setOnPreparedListener启动侦听器，并调用MediaPlayer的prepare（）方法
- 实现方法onPrepared。将mediaController与mediaPlayer链接，启动mediaPlayer，这里是使用处理程序调用方法show（）的地方，只有当我们知道mediaPlayer已准备就绪时
我的代码：
public class MainActivity extends Activity implements MediaPlayer.OnPreparedListener, MediaController.MediaPlayerControl {
private static final String TAG = "AudioPlayer";
private MediaPlayer mediaPlayer;
private MediaController mediaController;
private Handler handler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
protected void onStart() {
Log.d(TAG, "Play - onStart");
super.onStart();
mediaPlayer = new MediaPlayer();
mediaController = new MediaController(this);
mediaPlayer.setOnPreparedListener(this);
try {
AssetFileDescriptor afd = getApplicationContext().getResources().openRawResourceFd(R.raw.audio_example);
mediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getDeclaredLength());
mediaPlayer.prepare();
afd.close();
} catch (IOException e) {
Log.e(TAG, "Error opening audio: " + e.getCause());
}
}
// override this method because of the OnPreparedListener interface
@Override
public void onPrepared(MediaPlayer mediaPlayer) {
Log.d(TAG, "Play - onPrepared");
mediaController.setMediaPlayer(this);
mediaController.setAnchorView(findViewById(R.id.mediaController1));
mediaPlayer.start();
handler.post(new Runnable() {
@Override
public void run() {
mediaController.setEnabled(true);
mediaController.show(0);
}
});
}
// override these methods because of the MediaController.MediaPlayerControl interface
@Override
public boolean canPause() {
return true;
}
@Override
public boolean canSeekBackward() {
return true;
}
@Override
public boolean canSeekForward() {
return true;
}
@Override
public int getAudioSessionId() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int getBufferPercentage() {
// TODO Auto-generated method stub
return 0;
}
@Override
public int getCurrentPosition() {
return mediaPlayer.getCurrentPosition();
}
@Override
public int getDuration() {
return mediaPlayer.getDuration();
}
@Override
public boolean isPlaying() {
return mediaPlayer.isPlaying();
}
@Override
public void pause() {
mediaPlayer.pause();
}
@Override
public void seekTo(int pos) {
mediaPlayer.seekTo(pos);
}
@Override
public void start() {
mediaPlayer.start();
}
// release resources before kill the Activity
@Override
protected void onStop() {
Log.d(TAG, "Play - onStop");
super.onStop();
if (mediaPlayer != null) {
mediaController.hide();
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
}
} }
我需要向已经运行的MediaPlayer显示MediaController，所以我不能像e_v_e所说的那样设置OnPreparedListener
回答这个问题：我发现在调用所有活动生命周期方法之前，已经调用了show方法。这里提出的解决方案（将延迟设置为show）是可行的，但为了避免延迟，可以将show放在onAttachedToWindow方法中，该方法在所有活动生命周期方法之后调用。使用此方法
@Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if(mediaController != null)
mediaController.show(0);
}
只需将mediaPlayer.prepare（）和mediaPlayer.start（）放入类似线程的处理程序或异步任务中，即可完成。
如果您使用的是kotlin和anko库，那么可以将其放在doAsync{}中