multithreading - Post invalidate 方法在 Thread 类中有什么作用

Question

这是我的代码：

package com.example.analogclock;

    import android.view.View;


public class MyThread implements Runnable {

    private View view;

    public MyThread(View v){
        view = v;
    }

    public void run() {
        while(true){
            try {
                Thread.sleep(1000);
                view.postInvalidate();
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

}