画笔、鼠标监听

画笔、鼠标监听

```java
package com.zishi.lesson03;

import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Iterator;

public class TestMouseListener {
public static void main(String[] args) {
new MyFrame("画图");
}
}

class MyFrame extends Frame{
//画画需要画笔，需要监听鼠标当前的位置，需要集合来存储这个点
ArrayList points;

public MyFrame(String title){
super(title);
setBounds(200,200,400,300);
//存鼠标点击的点
points = new ArrayList<>();

setVisible(true);

//鼠标监听器，正对这个窗口
this.addMouseListener(new MyMouseListener());
}

@Override
public void paint(Graphics g) {
//画画，监听鼠标的事件
Iterator iterator = points.iterator();
while (iterator.hasNext()){
Point point = (Point) iterator.next();
g.setColor(Color.black);
g.fillOval(point.x,point.y,10,10);
}
}

//添加一个点到界面上
public void addPaint(Point point){
points.add(point);
}

//适配器模式
private class MyMouseListener extends MouseAdapter{
//鼠标，按下 弹起 按住不放

@Override
public void mousePressed(MouseEvent e) {
MyFrame frame = (MyFrame) e.getSource();
//这个我们点击的时候，就会在界面上产生一个点
//这个点就是鼠标的点
frame.addPaint(new Point(e.getX(),e.getY()));

//每次点击鼠标都需要重画一边，刷新
frame.repaint();
}
}
}
```