首次進入Activity、動畫卡頓問題的解決方案

初步思路，等待Activity的轉場動畫完成後，再開始頁面內的動畫

    /**
     * Activities cannot draw during the period that their windows are animating in. In order
     * to know when it is safe to begin drawing they can override this method which will be
     * called when the entering animation has completed.
     */
    public void onEnterAnimationComplete() {
    }