drag and drop - custom dragable icon in android -

package com.example.drag_drop_practice;  import android.os.bundle; import android.app.activity;  import android.view.motionevent; import android.view.view; import android.view.viewgroup; import android.widget.imageview; import android.widget.relativelayout;  public class mainactivity extends activity implements view.ontouchlistener {  private imageview mimageview; private viewgroup mrrootlayout; private int _xdelta; private int _ydelta;  @override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     mrrootlayout = (viewgroup) findviewbyid(r.id.root);     mimageview = (imageview) mrrootlayout.findviewbyid(r.id.imageview);      relativelayout.layoutparams layoutparams = new       relativelayout.layoutparams(150, 150);     mimageview.setlayoutparams(layoutparams);     mimageview.setontouchlistener(this); }  public boolean ontouch(view view, motionevent event) {     final int x = (int) event.getrawx();     final int y = (int) event.getrawy();     switch (event.getaction() & motionevent.action_mask) {     case motionevent.action_down:         relativelayout.layoutparams lparams = (relativelayout.layoutparams) view.getlayoutparams();         _xdelta = x - lparams.leftmargin;         _ydelta = y - lparams.topmargin;         break;     case motionevent.action_up:         break;     case motionevent.action_pointer_down:         break;     case motionevent.action_pointer_up:         break;     case motionevent.action_move:         relativelayout.layoutparams layoutparams = (relativelayout.layoutparams) view.getlayoutparams();         layoutparams.leftmargin = x - _xdelta;         layoutparams.topmargin = y - _ydelta;         layoutparams.rightmargin = -250;         layoutparams.bottommargin = -250;         view.setlayoutparams(layoutparams);         break;     }     mrrootlayout.invalidate();     return true; } } 

the icon in app draggable code.but problem not able allign scree in android.i mean icon been dragged out of view when drag icon @ border extreme ends.so should add in code,so icon not go beyond border in android.