java - 按下按钮后尝试绘画

Question

按下按钮后如何使其重新绘制？当我启动小程序时，它会在随机位置绘制 2 个具有随机宽度和高度的矩形，如何让它们在按下按钮后在不同位置“重生”？

package test;

import java.applet.Applet;
import java.awt.Button;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

public class Main extends Applet implements ActionListener{

    private static final long serialVersionUID = 1L;
    Thread thread = new Thread();
    boolean running = true;
    Random r = new Random();
    public int randX = r.nextInt(400);
    public int randY = r.nextInt(400);
    public int randW = r.nextInt(100);
    public int randH = r.nextInt(100);

    public int randX2 = r.nextInt(400);
    public int randY2= r.nextInt(400);
    public int randW2 = r.nextInt(100);
    public int randH2 = r.nextInt(100);


    public void start(){thread.start();}
    public void stop(){}
    public void init(){
        setSize(500,500);
        Button randomButton = new Button("RANDOMNESS");
        randomButton.addActionListener(this);
        add(randomButton);
    }

    public void run(){}
    public void destroy(){}

    public void paint(Graphics g){ //paints rect with random with and height
        g.fillRect(randX, randY, randW, randH);
        g.fillRect(randX2, randY2, randW2, randH2);
    }

    @Override
    public void actionPerformed(ActionEvent e) {// How can they repaint at a different random location after pressing the button?
        System.out.println("WORKING");

    }

}

Answer 1

您可以在您的 actionPerformed(...) 方法中简单地更改 randX、randY 等，方法是为它们提供新的随机值，就像您当前所做的那样，然后调用repaint() 来通知小程序重新绘制自身？

<小时/>

顺便说一句，这段代码应该做什么？

Thread thread = new Thread();

// .....

public void start(){thread.start();}

根据我的观点，它没有多大作用。