To retreive the screens width and height in pixels, we can make use of the WindowManagers display metrics.

// Get display metrics
DisplayMetrics metrics = new DisplayMetrics();
context.getWindowManager().getDefaultDisplay().getMetrics(metrics);

These DisplayMetrics hold a series of information about the devices screen, like its density or size:

// Get width and height in pixel
Integer heightPixels = metrics.heightPixels;
Integer widthPixels = metrics.widthPixels;