为什么 ImageView 在 SystemClock.sleep() 之前无法更新

why ImageView can#39;t update before SystemClock.sleep()(为什么 ImageView 在 SystemClock.sleep() 之前无法更新)

问题描述

我想在翻转旧图像之后的 3 秒内在 ImageView 中显示其他图像.代码:

I want to show other image in ImageView within 3 second, after that rollover old image. The code:

    OnClickListener oc = new OnClickListener() {
@Override
public void onClick(View v) {
         ImageView iv = (ImageView)v;
         iv.setImageResource(img2_id);
         SystemClock.sleep(3000);
         iv.setImageResource(img1_id);
    }
    }

    myImageView.setOnClickListener(oc);

但它不起作用?那么，我是不是做错了什么?

But it doesn't work? So, am I doing something wrong?

推荐答案

你阻塞了 UI 线程.因此在睡眠命令期间，屏幕不会刷新.您需要安排对更改图像资源的函数的非阻塞延迟调用.这是一个修改后的代码，可以做这样的事情:

You are blocking the UI thread. Thus during the sleep command, the screen won't refresh. What you need is to schedule a non-blocking delayed call to a function which changes image resource. Here is a modified code that would do such a thing:

Handler mHandler = new Handler(); /*handler declared in your Activity thread, I assume*/

OnClickListener oc = new OnClickListener() {
    @Override
    public void onClick(View v) {
        ImageView iv = (ImageView)v;
        iv.setImageResource(img2_id);

        mHandler.postDelayed(new Runnable(){
            public void Run(){
                iv.setImageResource(img1_id);
            }
        },3000);

    }
}
myImageView.setOnClickListener(oc);

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