Stopping/releasing Mediaplayer in onDestory() causes NullPointerException

Question

I'm trying to stop and release a MediaPlayer object in onDestroy(), but the app keeps crashing. Here is the code:

void StartSound(final String ReaderPath) {
    mediaplayer = MediaPlayer.create(test2.this, Uri.parse(ReaderPath));

    try {
        mediaplayer.start();
        mediaplayer.setOnCompletionListener(new OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                current++;
                try {
                    mp.reset();
                    mp.setDataSource(ReaderPath);
                    mp.prepare();

                } catch (Exception e) {
                    e.printStackTrace();
                }
                mp.start();

            }
        });

    } catch (Exception e) {

    }
}

@Override
    protected void onPause() {
        if (mediaplayer != null && mediaplayer.isPlaying())
            mediaplayer.pause();
        super.onPause();

    }

    @Override
    protected void onStop() {
        if (mediaplayer != null && mediaplayer.isPlaying()) {
            mediaplayer.release();
            mediaplayer.stop();
        }
        super.onDestroy();

    }

Logcat:

08-21 22:52:26.512: E/AndroidRuntime(16410): java.lang.RuntimeException: Unable to destroy activity {com.example.test/com.example.test.test2}: java.lang.NullPointerException
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3235)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3253)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread.access$1200(ActivityThread.java:132)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1190)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.os.Looper.loop(Looper.java:137)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread.main(ActivityThread.java:4575)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at java.lang.reflect.Method.invokeNative(Native Method)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at java.lang.reflect.Method.invoke(Method.java:511)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at dalvik.system.NativeStart.main(Native Method)
08-21 22:52:26.512: E/AndroidRuntime(16410): Caused by: java.lang.NullPointerException
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1406)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.support.v4.app.FragmentManagerImpl.dispatchDestroy(FragmentManager.java:1876)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.support.v4.app.FragmentActivity.onDestroy(FragmentActivity.java:316)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.Activity.performDestroy(Activity.java:4629)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1079)
08-21 22:52:26.512: E/AndroidRuntime(16410):    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3222)
08-21 22:52:26.512: E/AndroidRuntime(16410):    ... 11 more

Why is this?

Answer 1

Why are you calling super.onDestroy() from your onStop() method? You should be calling super.onStop(). Or is that a typing error?

The answer is probably that you are calling stop() on the MediaPlayer after you've called release(). Once you've called release() the MediaPlayer is invalidated and no longer available.