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Editorial Team
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Asked: 2026-06-10T22:46:26+00:00

I have a problem with Android media player, I’m working on some little quiz,

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I have a problem with Android media player, I’m working on some little quiz, and I have method correctAnswer(), where I create MediaPlayer with some sound, then prepare it, and then start it, but I get this NullPointerException error.

I am trying to play mp3 sound.

Here is that method correctAnswer():

    private void correctAnswer() {
    MediaPlayer correctSound = MediaPlayer.create(this, R.raw.correct);
    try {
        correctSound.prepare();
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    correctSound.start();

    Toast.makeText(getApplicationContext(), "Correct answer +1",
            Toast.LENGTH_SHORT).show();
    progressBar.incrementProgressBy(1);
    tvProgress.setText(progressBar.getProgress() + "/20");
    generateQuestion();
    endGame();
}

Here is LogCat:

09-04 21:21:30.546: E/AndroidRuntime(513): Uncaught handler: thread main exiting due to         uncaught exception
09-04 21:21:30.567: E/AndroidRuntime(513): java.lang.NullPointerException
09-04 21:21:30.567: E/AndroidRuntime(513):  at   com.example.americansportsquiz.PlayStageActivity.correctAnswer(PlayStageActivity.java:121)
09-04 21:21:30.567: E/AndroidRuntime(513):  at com.example.americansportsquiz.PlayStageActivity.onClick(PlayStageActivity.java:75)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.View.performClick(View.java:2364)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.View.onTouchEvent(View.java:4179)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.widget.TextView.onTouchEvent(TextView.java:6541)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.View.dispatchTouchEvent(View.java:3709)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
09-04 21:21:30.567: E/AndroidRuntime(513):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
09-04 21:21:30.567: E/AndroidRuntime(513):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
09-04 21:21:30.567: E/AndroidRuntime(513):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.os.Looper.loop(Looper.java:123)
09-04 21:21:30.567: E/AndroidRuntime(513):  at android.app.ActivityThread.main(ActivityThread.java:4363)
09-04 21:21:30.567: E/AndroidRuntime(513):  at java.lang.reflect.Method.invokeNative(Native Method)
09-04 21:21:30.567: E/AndroidRuntime(513):  at java.lang.reflect.Method.invoke(Method.java:521)
09-04 21:21:30.567: E/AndroidRuntime(513):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
09-04 21:21:30.567: E/AndroidRuntime(513):  at    com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
09-04 21:21:30.567: E/AndroidRuntime(513):  at dalvik.system.NativeStart.main(Native Method)

EDIT As I said, this is quiz app, and it play sound for 7 correct answers, but it fails on 8, and give me this null pointer expcetion. Before it fails at 8 correct answer it give me all time this warning.

09-04 21:41:33.086: W/MediaPlayer(598): info/warning (1, 44)
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1 Answer

  1. Editorial Team

    It looks like your are not releasing the previous MediaPlayer before you are trying to create a new one. Simply keep a reference to this MediaPlayer and replay the sound, rather than creating a new copy every time:

    MediaPlayer correctSound;

private void correctAnswer() {
    if(correctSound == null)
        correctSound = MediaPlayer.create(this, R.raw.correct);

        if(correctSound == null) {
           // Something failed... try again or break out of this method
        }

        try {
            correctSound.prepare();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    correctSound.start();
    ...
}
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