How to know exactly off screen size of the screen in android? -

i new android , have requirement when activity loaded 1 image view fit entire screen after 5 second fit off screen devices small ,medium , screens.because after getting off screen size want display in remain screen getting alignment issues in different devices.i have used below code screen size in galaxy s3 got more off screen size.please me.

 displaymetrics dm = new displaymetrics();      getwindowmanager().getdefaultdisplay().getmetrics(dm);      displayheight=dm.widthpixels;      displaywidth=dm.heightpixels; 

if want the display size in pixels can use getsize:

display display = getwindowmanager().getdefaultdisplay(); point size = new point(); display.getsize(size); int width = size.x; int height = size.y; 

if you're not in activity can default display via window_service:

windowmanager wm = (windowmanager) ctx.getsystemservice(context.window_service); display display = wm.getdefaultdisplay(); 

you can more information here