android - android准备dAsync

Question

如果我可以这样称呼自己，我就是新手，而且我的程序中有一个错误，我无法弄清楚如何修复它。我有一个使用流媒体源在线播放广播的小应用程序。

日志告诉我：

  > 12-09 21:32:35.207: W/WindowManager(60): Pointer down received while already down in: Window{450930b8 com.android.launcher/com.android.launcher2.Launcher paused=false}
    > 12-09 21:32:35.347: I/ActivityManager(60): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 .MainRadioActivity bnds=[174,147][230,206] } 
    > 21:32:35.777: I/Prefetcher(34): max cache size reached 12-09
    > 21:32:36.457: I/StagefrightPlayer(34):
    > setDataSource('http://64.71.133.122:8000') 12-09 21:32:36.717:
    > I/ActivityManager(60): Displayed activity MainRadioActivity: 1580 ms
    > (total 1580 ms) 12-09 21:32:36.821: I/Prefetcher(34): max cache size
    > reached 12-09 21:32:37.862: I/Prefetcher(34): max cache size reached
    > 12-09 21:32:38.902: I/Prefetcher(34): max cache size reached 12-09
    > 21:32:39.896: I/Prefetcher(34): max cache size reached
    >     12-09 21:32:40.736: E/MediaPlayer(1122): prepareAsync called in state 4
    >     12-09 21:32:40.736: D/AndroidRuntime(1122): Shutting down VM
    >     12-09 21:32:40.736: W/dalvikvm(1122): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122): FATAL EXCEPTION: main
    >     12-09 21:32:40.756: E/AndroidRuntime(1122): java.lang.IllegalStateException
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.media.MediaPlayer.prepareAsync(Native Method)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at com.example.***.MainRadioActivity.startPlaying(MainRadioActivity.java:65)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at com.example.***.MainRadioActivity.onClick(MainRadioActivity.java:55)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.view.View.performClick(View.java:2408)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.view.View$PerformClick.run(View.java:8816)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.os.Handler.handleCallback(Handler.java:587)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.os.Handler.dispatchMessage(Handler.java:92)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.os.Looper.loop(Looper.java:123)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at android.app.ActivityThread.main(ActivityThread.java:4627)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at java.lang.reflect.Method.invokeNative(Native Method)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at java.lang.reflect.Method.invoke(Method.java:521)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    >     12-09 21:32:40.756: E/AndroidRuntime(1122):   at dalvik.system.NativeStart.main(Native Method)
    >     12-09 21:32:40.776: W/ActivityManager(60):   Force finishing activity .......

这是我的代码：

public class MainRadioActivity extends Activity implements OnClickListener {

    private static String RADIO_STATION_URL = "http://64.71.133.122:8000";

    private Button buttonPlay;

    private Button buttonStopPlay;

    private MediaPlayer player;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_radio);

        initializeUIElements();

        initializeMediaPlayer();
    }

    private void initializeUIElements() {


        buttonPlay = (Button) findViewById(R.id.buttonPlay);
        buttonPlay.setOnClickListener(this);

        buttonStopPlay = (Button) findViewById(R.id.buttonStopPlay);
        buttonStopPlay.setEnabled(false);
        buttonStopPlay.setOnClickListener(this);

    }


    public void onClick(View v) {
        if (v == buttonPlay) {
            startPlaying();
        } else if (v == buttonStopPlay)
            stopPlaying();    
    }


    private void startPlaying() {
        buttonStopPlay.setEnabled(true);
        buttonPlay.setEnabled(false);



        player.setOnPreparedListener(new OnPreparedListener() {

            public void onPrepared(MediaPlayer mp) {
                player.start();
            }
        });
       player.prepareAsync();
    }

    private void stopPlaying() {
        if (player.isPlaying()) {
            player.stop();
            player.release();
            initializeMediaPlayer();
        }

        buttonPlay.setEnabled(true);
        buttonStopPlay.setEnabled(false);
    }

    private void initializeMediaPlayer() {
        player = new MediaPlayer();
        try {
            player.setDataSource(RADIO_STATION_URL);
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
}


    @Override
    protected void onPause() {
        super.onPause();
        if (player.isPlaying()) {
            player.stop();
        }
    }   
}

任何帮助是极大的赞赏 ：） ！

Answer 1

我想你忘记添加player.setAudioStreamType(AudioManager.STREAM_MUSIC);