画笔、窗口监听、鼠标监听、键盘监听

画笔

package com.tao.lesson03;

import java.awt.*;

public class TestPaint {
    public static void main(String[] args) {
        new MyPaint().loadFrame();
    }
}

class MyPaint extends Frame{
    public void loadFrame(){
        setBounds(200, 200, 600, 500);
        setVisible(true);
    }

    @Override
    public void paint(Graphics g) {
        g.setColor(Color.pink);
        g.drawOval(200,200,100,100);
        g.fillOval(100,100,100,100); //实心圆

        //养成习惯，画笔画完，还原为最初的颜色

    }
}

窗口监听

import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class TestWindow {
    public static void main(String[] args) {
        new WindowFrame();
    }
}

class WindowFrame extends Frame {
    public WindowFrame() {
        setBounds(100, 100, 100, 100);
        setBackground(Color.pink);
        setVisible(true);

        this.addWindowListener(
                //匿名内部类
                new WindowAdapter() {
                    @Override
                    public void windowClosing(WindowEvent e) {
                        //setVisible(false);//隐藏窗口
                        System.exit(0); //正常退出

                    }
                }
        );
    }

}

鼠标监听

目的：监听鼠标点击

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);

        //存鼠标的点
        points = new ArrayList<>();
        //鼠标监听器，针对这个窗口
        this.addMouseListener(new MyMouseListener());

        setVisible(true);
    }

    @Override
    public void paint(Graphics g) {
        //画画，监听鼠标的事件,迭代器
        Iterator iterator = points.iterator();
        while (iterator.hasNext()){
            Point point = (Point) iterator.next();
            g.setColor(Color.pink);
            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，都需要重画一次,刷新
            frame.repaint();
        }
    }
}

键盘监听

import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

public class TestKeyListener {
    public static void main(String[] args) {
        new KeyFrame();
    }
}

class KeyFrame extends Frame{
    public KeyFrame(){

        setBounds(1, 1, 300, 400);
        setVisible(true);
        this.addKeyListener(new KeyAdapter() {

            //键盘按下出现一个事件
            @Override
            public void keyPressed(KeyEvent e) {
                //获得键盘按下的键是哪一个，当前的码
                int keyCode = e.getKeyCode();
                if (keyCode==KeyEvent.VK_UP)
                    System.out.println("按下了向上键");
                if (keyCode==KeyEvent.VK_LEFT)
                    System.out.println("按下了向左键");
                if (keyCode==KeyEvent.VK_DOWN)
                    System.out.println("按下了向下键");
                if (keyCode==KeyEvent.VK_RIGHT)
                    System.out.println("按下了向右键");
            }
        });
    }
}