GUI编程(四)实现简易画板与设置鼠标和键盘监听

7.画笔

package com.study.lesson03;

import java.awt.*;

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

class MyPaint extends Frame {

    public void loadFrame(){
        setBounds(200,200,600,400);
        setVisible(true);
    }
    //画笔
    @Override
    public void paint(Graphics g) {
        //画笔，需要有颜色，画笔可以画画
        g.setColor(Color.red);
        //g.drawOval(100,100,100,100);
        g.fillOval(100,100,100,100);//实心的圆

        //g.setColor(Color.GREEN);
        g.fillRect(150,200,200,200);

        //养成习惯，画笔用完，将他还原到最初的颜色
    }
}

8、鼠标监听

目的：想要实现鼠标画画

package com.study.lesson03;

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

//测试鼠标监听事件
public class TestMouseListener {
    public static void main(String[] args) {
        new MyFrame("画图");

    }
}

//自己的类
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<>();
        //鼠标监听器，正对这个窗口
        this.addMouseListener(new MyMouseListener());


        setVisible(true);
    }

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

    //添加一个点到界面上
    public void addPoint(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.addPoint(new Point(e.getX(),e.getY()));

            //每次点击鼠标都需要重新画一遍
            frame.repaint();//刷新
        }
    }

}

9、窗口监听

package com.study.lesson03;

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

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

class WindowsFrame extends Frame{
    public WindowsFrame(){
        setBackground(Color.blue);
        setBounds(100,100,200,200);
        setVisible(true);
        //addWindowListener(new MyWindowListener());

        this.addWindowListener(
                //匿名内部类
                new WindowAdapter() {
                    //关闭窗口
                    @Override
                    public void windowClosing(WindowEvent e) {
                        System.out.println("windowClosing");
                        System.exit(0);
                    }

                    //激活窗口
                    @Override
                    public void windowActivated(WindowEvent e) {
                        WindowsFrame source = (WindowsFrame) e.getSource();
                        System.out.println("windowActivated");
                    }


                }
        );
    }


}

10、键盘监听

package com.study.lesson03;

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

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

class KeyFrame extends Frame{
    public KeyFrame(){
        setBounds(1,2,300,400);
        setVisible(true);

        this.addKeyListener(new KeyAdapter() {
            //键盘按下
            @Override
            public void keyPressed(KeyEvent e) {
                //键盘按下的键是哪一个,当前的码
                int keyCode = e.getKeyCode();//不需要记录这个数值，直接使用静态属性 VK_XXX
                System.out.println(keyCode);
                if  (keyCode == KeyEvent.VK_UP) {
                    System.out.println("你按下了上键");
                }
                //根据按下不同操作，产生不同结果
            }
        });
    }
}