How to get android device screen size?

try this code to get screen size in inch

DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int width=dm.widthPixels;
int height=dm.heightPixels;
double wi=(double)width/(double)dm.xdpi;
double hi=(double)height/(double)dm.ydpi;
double x = Math.pow(wi,2);
double y = Math.pow(hi,2);
double screenInches = Math.sqrt(x+y);

This won't work?

DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
double x = Math.pow(dm.widthPixels / dm.xdpi, 2);
double y = Math.pow(dm.heightPixels / dm.ydpi, 2);
double screenInches = Math.sqrt(x + y);
Log.d("debug", "Screen inches : " + screenInches);