MainActivity.java

    public static int getDimensionForName(String resourceName, Context ctx) {
        int result = 0;
        int resourceId = ctx.getResources().getIdentifier(resourceName, "dimen", "android");
        if (resourceId > 0) {
            result = ctx.getResources().getDimensionPixelSize(resourceId);
        }
        return result;
    }

    public static int getNotificationBarHeight(Context ctx) {
        return getDimensionForName("status_bar_height", ctx);
    }

    public static int getNavigationBarHeight(Context ctx) {
        return getDimensionForName("navigation_bar_height", ctx);
    }

    public static int getActionBarHeight(Context ctx) {
        return (int) ctx.getResources().getDimension(R.dimen.abc_action_bar_default_height);
    }