Android 获取 屏幕状态栏高度和标题栏高度 避免出现0的情况

@Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);  

        Rect frame = new Rect();
        getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
        int statusBarHeight = frame.top;
        // 获取标题栏高度
        Window window = getWindow();
        int contentViewTop = getWindow()
                .findViewById(Window.ID_ANDROID_CONTENT).getTop();
        // statusBarHeight是上面所求的状态栏的高度
        titleBarHeight = contentViewTop - statusBarHeight;  

        Log.i("test", "statusBarHeight=" + statusBarHeight + " contentViewTop="
                + contentViewTop + " titleBarHeight=" + titleBarHeight);
    }