java - Cannot refer to the non-final local variable button defined in an enclosing scope, Random method error -

i getting error in project eclipse:

cannot refer non-final local variable button defined in enclosing scope 

this class:

import android.app.activity; import android.content.context; import android.graphics.point; import android.os.bundle; import android.support.annotation.nonnull; import android.widget.button; import android.view.menu; import android.view.menuitem; import android.view.windowmanager;  import java.util.random; import java.util.timer; import java.util.timertask;  public class mainactivity extends activity { button buttonblack; @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);       buttonblack = (button)findviewbyid(r.id.button01);       startrandombutton(buttonblack);      }  public static point getdisplaysize(@nonnull context context) {     point point = new point();     windowmanager manager = (windowmanager) context.getsystemservice(context.window_service);     manager.getdefaultdisplay().getsize(point);     return point; }  private void setbuttonrandomposition(button button){     int randomx = new random().nextint(getdisplaysize(this).x);     int randomy = new random().nextint(getdisplaysize(this).y);      button.setx(randomx);     button.sety(randomy); }  private void startrandombutton(button button) {     timer timer = new timer();     timer.schedule(new timertask() {         @override         public void run() {             setbuttonrandomposition(button);         }     }, 0, 1000);//update button every second } @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; }  @override public boolean onoptionsitemselected(menuitem item) {     // handle action bar item clicks here. action bar     // automatically handle clicks on home/up button, long     // specify parent activity in androidmanifest.xml.     int id = item.getitemid();     if (id == r.id.action_settings) {         return true;     }     return super.onoptionsitemselected(item); } } 

the problem in method:

private void startrandombutton(button button) {         timer timer = new timer();         timer.schedule(new timertask() {             @override             public void run() {                 setbuttonrandomposition(button);// cannot refer non-final local variable button defined in enclosing scope             }         }, 0, 1000);//update button every second     } 

can me fix this? or suggest other code better this?

you have declared button buttonblack; globally in mainactivity..

you can pass buttonblack setbuttonrandomposition(buttonblack); without referring final.