http://stackoverflow.com/questions/1016896/get-screen-dimensions-in-pixels

WindowManager w = activity.getWindowManager();
Display d = w.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
d.getMetrics(metrics);
// since SDK_INT = 1;
widthPixels = metrics.widthPixels;
heightPixels = metrics.heightPixels;
try {
    // used when 17 > SDK_INT >= 14; includes window decorations (statusbar bar/menu bar)
    widthPixels = (Integer) Display.class.getMethod("getRawWidth").invoke(d);
    heightPixels = (Integer) Display.class.getMethod("getRawHeight").invoke(d);
} catch (Exception ignored) {
}
try {
    // used when SDK_INT >= 17; includes window decorations (statusbar bar/menu bar)
    Point realSize = new Point();
    Display.class.getMethod("getRealSize", Point.class).invoke(d, realSize);
    widthPixels = realSize.x;
    heightPixels = realSize.y;
} catch (Exception ignored) {
}

EDIT: slightly improved version (avoid firing exceptions on non-supported OS version):