java - Android MediaPlayer not stopping by clicking another button -

when click on 2 buttons hear 2 sounds. how can stop first sound , play second sound or when play first sound, second sound stops? how can create this? here media player

final linearlayout lm = (linearlayout) findviewbyid(r.id.linearmain);                         linearlayout.layoutparams params = new linearlayout.layoutparams(                         layoutparams.wrap_content, layoutparams.wrap_content);                         jsonarray songs = (jsonarray) response.getjsonarray("songs");                         ( int = 0; < songs.length(); i++)                          {                             // create linearlayout                            audio = songs.getjsonobject(i).getstring(tag_audio) ;                            string chanson = songs.getjsonobject(i).getstring("title") ;                            string duration = songs.getjsonobject(i).getstring(tag_duration) ;                             linearlayout ll = new linearlayout(getapplicationcontext());                            ll.setorientation(linearlayout.horizontal);                             final textview txtchanson = new textview(getapplicationcontext());                            txtchanson.settext(chanson);                            txtchanson.setpadding(10, 0, 10, 0);                            textview txtduration = new textview(getapplicationcontext());                            txtduration.settext(duration);                             final button btn = new button(getapplicationcontext());                            final mediaplayer mp = new mediaplayer();                             mp.setaudiosessionid(i+1);                             mp.setdatasource(audio);                             mp.prepare();                             btn.setid(i+1);                            btn.settypeface(ionicons);                            btn.settext(getstring(r.string.play_str));                            btn.setlayoutparams(params);                             final int index = i;                            mp.setoncompletionlistener(new oncompletionlistener()                               {                                   public void oncompletion(mediaplayer mp)                                   {                                       btn.settext(getstring(r.string.play_str));                                  }                              });                               btn.setonclicklistener(new view.onclicklistener() {                                     public void onclick(view v)                                      {                                           log.i("tag", "index :" + index);                                         toast.maketext(getapplicationcontext(),                                                  "clicked button index :" +  btn.getid(),                                                  toast.length_long).show();                                         boolean b = false ;                                         if ( b == false )                                          {                                              //txtchanson.settextcolor(r.color.green);                                             mp.start();                                             btn.settext(getstring(r.string.pause_str));                                             b = true;                                          }                                          else //if (btn.gettext().equals( getstring(r.string.pause_str)))                                         {                                             mp.pause();                                             btn.settext(getstring(r.string.play_str));                                             //txtchanson.settextcolor(r.color.gray);                                             b = false;                                          }                                     /*  else if (b == true )                                         {                                             btn.settext(getstring(r.string.play_str));                                             mp.pause();                                         }*/                                     }                                 });                                ll.addview(btn);                              ll.addview(txtchanson);                              ll.addview(txtduration);                               lm.addview(ll);                            } 

you should place boolean b = false ; line out of onclick method should global variable, because on every click, when go onclick method, b variable gets false value , never steps else clause of if-else statement. else okay.