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我正在为我的应用程序中的音频模块工作，所以我创建了简单的音频演示与服务。媒体播放器中停止服务后音频不播放
它的工作可达Play - Pause - Playing in Background但问题很奇怪。
简单而推出的应用程序，我已经添加了两个按钮像
Play/Pause（会改变按标题状态）stop（停止服务）
现在我说我的play-pause & Stop工作正常，但当我尝试播放音频后点击stop它的原因在Start
Error : 05-01 13:37:42.671: E/start(8096): java.lang.IllegalStateException
问题Audio_Activity.java
public class Audio_Activity extends Activity {
private static final String TAG = "ServicesDemo";
public static Button play_pause;
public static Button buttonStop;
Audio_Service ms;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ms = new Audio_Service();
play_pause = (Button) findViewById(R.id.play_pause);
buttonStop = (Button) findViewById(R.id.buttonStop);
play_pause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (isMyServiceRunning()) {
ms.play_pause();
} else {
startService(new Intent(Audio_Activity.this,
Audio_Service.class));
play_pause.setText("Pause");
}
}
});
buttonStop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (isMyServiceRunning()) {
ms.stop_audio();
stopService(new Intent(Audio_Activity.this,
Audio_Service.class));
play_pause.setText("Play");
} else {
stopService(new Intent(Audio_Activity.this,
Audio_Service.class));
play_pause.setText("Play");
}
}
});
}
public boolean isMyServiceRunning() {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service: manager
.getRunningServices(Integer.MAX_VALUE)) {
if (Audio_Service.class.getName().equals(
service.service.getClassName())) {
return true;
}
}
return false;
}
}
Audio_Service.java
public class Audio_Service extends Service implements OnErrorListener,
OnCompletionListener, OnPreparedListener {
public static MediaPlayer player = new MediaPlayer();
Audio_Activity ac = new Audio_Activity();
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
Toast.makeText(this, "My Service Created", Toast.LENGTH_LONG).show();
}
@Override
public void onDestroy() {
try {
Toast.makeText(this, "My Service Stopped", Toast.LENGTH_LONG)
.show();
} catch (Exception e) {
Log.e("ONdistroy", "" + e);
}
}
@Override
public void onStart(Intent intent, int startid) {
Toast.makeText(this, "My Service Started", Toast.LENGTH_LONG).show();
try {
Log.e("player_status", "" + player);
String url = "MY_WEB_URL";
player.setAudioStreamType(AudioManager.STREAM_MUSIC);
player.reset();
player.setDataSource(url);
player.prepareAsync();
player.setOnPreparedListener(this);
player.setOnErrorListener(this);
player.setOnCompletionListener(this);
} catch (Exception e) {
// TODO: handle exception
Log.e("start", "" + e);
}
// player.start();
}
public void play_pause() {
try {
if (player != null) {
if (player.isPlaying()) {
ac.play_pause.setText("Play");
player.pause();
} else {
ac.play_pause.setText("Pause");
player.start();
}
}
} catch (Exception e) {
// TODO: handle exception
Log.e("play_pause", "" + e);
}
}
public void stop_audio() {
try {
if (player != null) {
if (player.isPlaying()) {
ac.play_pause.setText("Play");
player.stop();
player.release();
} else {
ac.play_pause.setText("Play");
player.release();
}
}
} catch (Exception e) {
// TODO: handle exception
Log.e("stop_service", "" + e);
}
}
public void cleanUp() {
if (player != null) {
player.stop();
player = null;
player.release();
}
}
@Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
try {
Log.d("complete", "called...........");
player.stop();
player.release();
player = null;
stopService(new Intent(this, Audio_Service.class));
ac.play_pause.setText("Play");
} catch (Exception e) {
// TODO: handle exception
Log.e("complete", "" + e);
}
}
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
// TODO Auto-generated method stub
try {
player.stop();
player.release();
player = null;
// mp.reset();
ac.play_pause.setText("Play");
} catch (Exception e) {
// TODO: handle exception
Log.e("onError", "" + e);
}
return false;
}
@Override
public void onPrepared(MediaPlayer mp) {
// TODO Auto-generated method stub
try {
player.start();
} catch (Exception e) {
// TODO: handle exception
Log.e("onPrepare", "" + e);
}
}
}
我已经添加下面的东西Manifest文件
<uses-permission android:name="android.permission.INTERNET"/>
<service
android:name=".Audio_Service"
android:enabled="true" />
更新
我知道我可以在理想状态下播放音频的，我必须设置reset();但不知道在哪里。因为如果我设置了onDestroy;或cleanUp()或stop_audio()或onStart()然后再增加一个错误，那就是NullpointerException。
请大家帮帮我。这个错误是我最近两天得到的。 纠正我，如果我错了。
坦克需要你的时间在我的问题。
我有打电话给我服务'startService（新意图（Audio_Activity.this，Audio_Service.class））;''中点击play_pause'事件 – 2013-05-01 09:17:18
但你自己创建新的使用实例，您使用与此实例communicatate常规方法调用。这不是如何使用服务。在调用startService（）之后，您需要让OS自己创建实例。您需要等待连接到srevice才能建立，并且您需要使用活页夹与它进行通信。请参阅链接查看更多细节。 – selalerer 2013-05-01 10:22:58
感谢您的链接。这很好。但我解决了我的问题，我必须在'stop_audio（）'中添加'player = null;'。 – 2013-05-01 10:34:41