原始文件夹中的音频文件出现问题

Question

我想播放 /src/res/raw 文件夹中的音频文件，如下所示：

 public class SayItActivity extends Activity {
 private ImageButton SayLetterImgBtn;
 private MediaPlayer mp;     
 @Override
 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);



    SayLetterImgBtn=(ImageButton) findViewById(R.id.sayletter);
    SayLetterImgBtn.setOnClickListener(new OnClickListener() {
        public void onClick(View view) {

            mp = MediaPlayer.create(SayItActivity.this, R.raw.a);   
            mp.start();
            mp.setOnCompletionListener(new OnCompletionListener() {

                @Override
                public void onCompletion(MediaPlayer mp) {
                    // TODO Auto-generated method stub
                    mp.release();
                }

            });
        }

    });

}
}

Logcat

09-08 15:13:16.692: ERROR/AndroidRuntime(477): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.mds.sayit/com.android.mds.sayit.SayItActivity}: java.lang.NullPointerException
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.os.Looper.loop(Looper.java:123)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at android.app.ActivityThread.main(ActivityThread.java:4627)
09-08 15:13:16.692: ERROR/AndroidRuntime(477):     at java.lang.reflect.Method.invokeNative(Native Method)
09-08 15:13:16.692: ERROR/AndroidRuntime(477): Caused by: java.lang.NullPointerException
09-08 15:13:16.713: WARN/ActivityManager(59):   Force finishing activity  com.android.mds.sayit/.SayItActivity

我该如何处理？

谢谢

Answer 1

替换为 ::

private MediaPlayer mp;  

以

MediaPlayer mp_xmPlayer2 = new MediaPlayer(),

更新 ::

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

Answer 2

您尚未在媒体播放器上调用准备方法。

基本上，要使用媒体播放器，您需要调用prepare()。然后媒体播放器准备媒体管道并在准备完成时通知应用程序。只有这样你才能在媒体播放器上调用start()。

让我知道这是否有效。

沙什