get null pointer error when loading the sounds into soundpool

Question

what am I doing wrong? any help would be greatly apreciated the log shows the initAudio method called and sound pool created then crashes

 public class soundEffects extends Activity{
    SoundPool sp;
    int shot = 0;
    public void InitializeAudio(){
    Log.d("TEST", "initAudio method called");
       sp = new SoundPool(1, AudioManager.STREAM_MUSIC, 0);
       Log.d("TEST", "sound pool created sp= " + sp);
       shot = sp.load(this, R.raw.gunshot, 1);
       Log.d("TEST", "Audio is loaded :)");
    }

    public void fireSound(){
        Log.d("TEST", "fire sound method works");
        sp.play(shot, 1, 1, 0,0, 1);
        Log.d("TEST", "fire sound command sucessful");

    }


    }

Stack Trace(I think this is it) -----------------------------------------------------------

12-24 11:31:43.074: E/AndroidRuntime(14617): FATAL EXCEPTION: main
12-24 11:31:43.074: E/AndroidRuntime(14617): Process: com.example.firedatgun_v2, PID: 14617
12-24 11:31:43.074: E/AndroidRuntime(14617): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.firedatgun_v2/com.example.firedatgun_v2.Display}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2232)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2282)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread.access$800(ActivityThread.java:136)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1225)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.os.Handler.dispatchMessage(Handler.java:102)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.os.Looper.loop(Looper.java:136)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread.main(ActivityThread.java:5186)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at java.lang.reflect.Method.invoke(Native Method)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1015)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:831)
12-24 11:31:43.074: E/AndroidRuntime(14617): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.content.ContextWrapper.getResources(ContextWrapper.java:89)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.media.SoundPool$SoundPoolImpl.load(SoundPool.java:491)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.media.SoundPool.load(SoundPool.java:159)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at com.example.firedatgun_v2.soundEffects.InitializeAudio(soundEffects.java:15)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at com.example.firedatgun_v2.gun.reload(gun.java:32)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at com.example.firedatgun_v2.Display.onCreate(Display.java:26)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.Activity.performCreate(Activity.java:5231)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1098)
12-24 11:31:43.074: E/AndroidRuntime(14617):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2196)
12-24 11:31:43.074: E/AndroidRuntime(14617):    ... 9 more

Where do you get the exception? Which line? Can we see the stack trace? — But I'm Not A Wrapper Class, Dec 24 '13 at 19:21
It seems like `sp` is null. However, looking at your code that should be impossible. Try to print its value to the log. Next time, please add the stacktrace as well. — Jeffrey Klardie, Dec 24 '13 at 19:21
Also, please start following Java naming conventions - `PascalCase` for classes; `camelCase` for methods. It'll make it a lot easier for anyone else to read your code. — Jon Skeet, Dec 24 '13 at 19:24
12-24 11:24:51.935: D/TEST(14027): sound pool created sp= android.media.SoundPool@64b2b530 — coderguy22296, Dec 24 '13 at 19:26
That's not the stack trace. That's the logger statement you have. Can you post the stack trace: http://stackoverflow.com/questions/3988788/what-is-a-stack-trace-and-how-can-i-use-it-to-debug-my-application-errors — But I'm Not A Wrapper Class, Dec 24 '13 at 19:28
It seems to be failing here: `sp.load(this, R.raw.gunshot, 1);` Does `R.raw` and `R.raw.gunshot` exist? What about the `Context` (`this`)? — But I'm Not A Wrapper Class, Dec 24 '13 at 19:43
It has been solved, look at the answer below, I know that was the problematic like e of code. — coderguy22296, Dec 26 '13 at 21:07

score 1 · Accepted Answer · answered Dec 24 '13 at 19:50

You're referencing an invalid Activity, in this case the soundEffect class. Just extending the Activity class won't give you all the pleasures of an Activity unless that Activity is explicitly called with onCreate(...) to set-up resources, etc.

You can remove the "extends Activity" from you soundEffects class, and instead, replace your

public void InitializeAudio()
{
   Log.d("TEST", "initAudio method called");
   sp = new SoundPool(1, AudioManager.STREAM_MUSIC, 0);
   Log.d("TEST", "sound pool created sp= " + sp);
   shot = sp.load(this, R.raw.gunshot, 1);
   Log.d("TEST", "Audio is loaded :)");
}

with

public void InitializeAudio(Context context)
{
   Log.d("TEST", "initAudio method called");
   sp = new SoundPool(1, AudioManager.STREAM_MUSIC, 0);
   Log.d("TEST", "sound pool created sp= " + sp);
   shot = sp.load(context, R.raw.gunshot, 1);
   Log.d("TEST", "Audio is loaded :)");
}

And pass a reference from you main Activity, which would appear to be your Display class, up through gun.reload(..), which should be gun.reload(Context context).

i did that and passed getBaseContext() to the method InitializeAudio, thank you, I really appreciate your help — coderguy22296, Dec 24 '13 at 20:13

get null pointer error when loading the sounds into soundpool

1 Answers1