media player - Android MediaPlayer not playing sounds on button click -

i'm new android , need project i'm working on. need play sound clicking button. followed online tutorials code not play sounds @ , i'm getting error on mediaplayer error(-19,0). i've tried lot of fixes saw here , can't seem make work. help? here's code

import android.media.audiomanager; import android.media.mediaplayer; import android.media.mediaplayer.oncompletionlistener; import android.os.bundle; import android.app.activity; import android.view.menu; import android.view.view; import android.widget.button;  public class mainactivity extends activity {     mediaplayer player;      @override     protected void oncreate(bundle savedinstancestate) {         try {             super.oncreate(savedinstancestate);             setcontentview(r.layout.activity_main);              audiomanager audiomanager = (audiomanager)     getsystemservice(mainactivity.audio_service);             audiomanager.setstreamvolume(audiomanager.stream_music, 20, 0);              button buttonhello = (button) findviewbyid(r.id.button1);             buttonhello.setonclicklistener(new view.onclicklistener() {                 @override                 public void onclick(view v) {                     mediaplayer mp = medi    aplayer.create(mainactivity.this, r.raw.button);                     mp.start();                     mp.setoncompletionlistener(new oncompletion    listener() {                         public void oncompletion(mediaplayer mp) {                             mp.release();                          };                     });                 }             });         } catch (exception e) {             system.out.println("error!");         }      }      @override     public boolean oncreateoptionsmenu(menu menu) {         // inflate menu; adds items action bar if present.         getmenuinflater().inflate(r.menu.main, menu);         return true;     }  } 

this links http://marakana.com/forums/android/examples/59.html has great example use mediaplayer class play song raw folder.

to play song files in memory can use following code.

 mediaplayer mp = new mediaplayer();          mp.reset();          contentvalues values = new contentvalues();                                 values.put(mediastore.images.media.data, filename.getabsolutepath());           uri selectedimage=ringtonedownload.this.getcontentresolver().insert(                           mediastore.images.media.external_content_uri, values);                         try {                             mp.setdatasource(ringtonedownload.this,selectedimage);                             mp.prepare();                             mp.start();                         }catch (exception e) {                             // todo auto-generated catch block                             e.printstacktrace();                         } 

this code working me while set source file.