ScrollView中smoothScrollTo()方法无效

最近在写一个自定义的View继承于ScrollView时出现了一个问题，就是调用smoothScrollTo()方法时不起作用了，scrollTo()方法是没有问题的，但我们想要一种平滑的效果，所以就得使用smoothScrollTo()方法。网上找了好多方法，只有一种方法目前是有效的，就是使用post()方法，具体如下：

this.post(new Runnable() {  
    @Override  
    public void run() {  
        smoothScrollTo(0, 0);  
    }  
}); 

/**
     * <p>Causes the Runnable to be added to the message queue.
     * The runnable will be run on the user interface thread.</p>
     * 
     * <p>This method can be invoked from outside of the UI thread
     * only when this View is attached to a window.</p>
     *
     * @param action The Runnable that will be executed.
     *
     * @return Returns true if the Runnable was successfully placed in to the
     *         message queue.  Returns false on failure, usually because the
     *         looper processing the message queue is exiting.
     */
    public boolean post(Runnable action) {
        Handler handler;
        AttachInfo attachInfo = mAttachInfo;
        if (attachInfo != null) {
            handler = attachInfo.mHandler;
        } else {
            // Assume that post will succeed later
            ViewRootImpl.getRunQueue().post(action);
            return true;
        }
 
        return handler.post(action);
    }

看到注释中的第二行，再看看代码中的Handler，有没有一种很熟悉的感觉呢----通过Handler发送消息到主线程中对界面进行更新。当然这只是看到这两行代码后的初步猜想，具体的原理在下面的链接中有解释，其中的涉及的Handler及其内部类和关联类的知识点需要深度学习：

http://www.cnblogs.com/akira90/archive/2013/03/06/2946740.html