android - Can't handle with Handler -

i playing music form sd card , want seekbar getprogress every 2 sec when music playing. trying handler. dont know how use handler coretly here code:

@override protected void oncreate(bundle savedinstancestate)  {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      seekbar1 = (seekbar) findviewbyid(r.id.seekbar1);     button1 = (button) findviewbyid(r.id.button1);     button2 = (button) findviewbyid(r.id.button2);     textview1 = (textview) findviewbyid(r.id.textview1);        button1.setonclicklistener(new onclicklistener()      {          @override         public void onclick(view v)          {             mediaplayer mediaplayer = new mediaplayer();             try {                 mediaplayer.setdatasource(environment.getexternalstoragedirectory()+"/myimages/.audio2.wav");                 mediaplayer.prepare();                 mediaplayer.start();              } catch (illegalargumentexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (securityexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (illegalstateexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (ioexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }                      setuphandler();          }     }); } private void setuphandler() {   handler.removecallbacks(moveseekbarthread);   handler.postdelayed(moveseekbarthread, 2000); //cal thread after  millisec } private runnable moveseekbarthread = new runnable() {      public void run() {          if(mediaplayer.isplaying()){          int mediapos = mediaplayer.getcurrentposition();         int mediamax = mediaplayer.getduration();         seekbar1.setmax(mediamax);         seekbar1.setprogress(mediapos);          handler.postdelayed(this, 2000); //looping thread after  second                                         // seconds         }       } }; 

}

my app crashing 2 second after clikc button1. sure problem here handler. call handler wrong or something?

post logcat when ask app crashes. therefor in case have nullpointerexception here, think: if(mediaplayer.isplaying()) doesn't initialize mediaplayer variable.

edited:

mediaplayer mediaplayer;     @override protected void oncreate(bundle savedinstancestate)  {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     seekbar1 = (seekbar) findviewbyid(r.id.seekbar1);     button1 = (button) findviewbyid(r.id.button1);     button2 = (button) findviewbyid(r.id.button2);     textview1 = (textview) findviewbyid(r.id.textview1);        button1.setonclicklistener(new onclicklistener()      {          @override         public void onclick(view v)          {             mediaplayer = new mediaplayer();             try {                 mediaplayer.setdatasource(environment.getexternalstoragedirectory()+"/myimages/.audio2.wav");                 mediaplayer.prepare();                 mediaplayer.start();              } catch (illegalargumentexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (securityexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (illegalstateexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             } catch (ioexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }                      setuphandler();          }     }); } private void setuphandler() {   handler.removecallbacks(moveseekbarthread);   handler.postdelayed(moveseekbarthread, 2000); //cal thread after  millisec } private runnable moveseekbarthread = new runnable() {      public void run() {          if(mediaplayer.isplaying()){          int mediapos = mediaplayer.getcurrentposition();         int mediamax = mediaplayer.getduration();         seekbar1.setmax(mediamax);         seekbar1.setprogress(mediapos);          handler.postdelayed(this, 2000); //looping thread after  second                                         // seconds         }       } };