02 画笔

2.7 画笔

package com.mysoft.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);
    }

    //画笔
    @Override
    public void paint(Graphics g) {
        //super.paint(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，将它还原到最初的颜色

    }
}

实行效果：

2.8 鼠标监听

目的：实现鼠标画画

TestMouseListener.java

package com.mysoft.lesson03;

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

//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<Point> points;

    public MyFrame(String title)  {
        super(title);
        setBounds(200,200,400,400);
        setVisible(true);

        //存鼠标点击的点
        points = new ArrayList<>();

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

    @Override
    public void paint(Graphics g) {
        //画画，监听鼠标的事件
        System.out.println("paint(Graphics g) called!");
        Iterator<Point> iterator = points.iterator();
        while (iterator.hasNext()) {
            Point point = (Point) iterator.next();
            g.setColor(Color.blue);
            g.fillOval(point.x,point.y,10,10);
        }

    }

    //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) {
            System.out.println("MyMouseListener =>" + e.getX()+", "+e.getY());
            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.points.add(new Point(e.getX(), e.getY()));

            //每次点击鼠标都重新画一遍！
            frame.repaint();//刷新  30帧 60帧
        }
    }

}

实行效果图：

　

思维导图：

2.9 窗口监听

窗口监听一般用的比较少，主要是键盘监听！

TestWindow.java

package com.mysoft.lesson03;

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, 400, 400);
        setBackground(Color.blue);
        setVisible(true);

        addWindowListener(new MyWindowListener());
    }

    class MyWindowListener extends WindowAdapter {
        @Override
        public void windowClosing(WindowEvent e) {
            setVisible(false);//隐藏窗口，通过按钮，隐藏窗口
            System.exit(0);//正常退出
        }
    }
}

实行效果：

匿名内部类，建议这么写

package com.mysoft.lesson03;

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, 400, 400);
        setBackground(Color.blue);
        setVisible(true);

        //addWindowListener(new MyWindowListener());
        //匿名内部类
        this.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }

    class MyWindowListener extends WindowAdapter {
        @Override
        public void windowClosing(WindowEvent e) {
            setVisible(false);//隐藏窗口，通过按钮，隐藏窗口
            System.exit(0);//正常退出
        }
    }
}

2.10 键盘监听

TestKeyListener.java

package com.mysoft.lesson03;

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

//键盘监听
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) {
                //获得键盘按下的是哪个键，当前的码
                int keyCode = e.getKeyCode();//不需要去记录这个数值，直接使用静态属性 VK_XXX
                System.out.println(keyCodes);
                if (keyCode == KeyEvent.VK_UP) {
                    System.out.println("你按下了上键");
                }

                //根据按下的键，产生不同的结果
            }

        });
    }
}