Statusbarのサイズ(高さ)を取得する。 ref: http://qiita.com/Rompei/items/4f83ab38f416b60897cb

file0.java

     /**
     * Return Statusbar size.
     * @param activity Activity
     * @return Statusbar size
     */
    public static int getStatusBarHeight(Activity activity){
        final Rect rect = new Rect();
        Window window = activity.getWindow();
        window.getDecorView().getWindowVisibleDisplayFrame(rect);
        return rect.top;
    }