GUI编程 续

GUI编程

1.事件监听

事件监听：当某个事情发生的时候，干什么？

package com.tian.lesson02;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class TestActionEvent {
    public static void main(String[] args) {
        //按下按钮，触发一些事件
        Frame frame = new Frame();
        Button button = new Button();
        //因为，addActionListener()需要一个ActionListener，所以我们需要构造一个ActionListener
        MyActionListener myActionListener = new MyActionListener();
        button.addActionListener(myActionListener);
        frame.add(button,BorderLayout.CENTER);
        frame.pack();
        windowClose(frame);//关闭窗口
        frame.setVisible(true);
    }
    //关闭窗体的事件
    private static void windowClose(Frame frame){
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
}
//事件监听
class MyActionListener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println("aaa");
    }
}

多个按钮，共享一个事件

package com.tian.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestActionTwo {
    public static void main(String[] args) {
        //两个按钮，实现同一个监听
        Frame frame = new Frame("开始-停止");
        Button button1 = new Button("start");
        Button button2 = new Button("stop");
        //可以显示的定义触发会返回的命令。如果不显示定义，则会走默认的值！
        //可以多个按钮只写一个监听类
        button2.setActionCommand("button2-stop");

        MyMonitor myMonitor = new MyMonitor();

        button1.addActionListener(myMonitor);
        button2.addActionListener(myMonitor);

        frame.add(button1,BorderLayout.NORTH);
        frame.add(button2,BorderLayout.SOUTH);

        frame.pack();
        frame.setVisible(true);
    }
}
class MyMonitor implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        //e.getActionCommand()获得按钮的信息
        System.out.println("按钮被点击了：msg=> "+e.getActionCommand());
    }
}

2.输入框TextField监听

package com.tian.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestText01 {
    public static void main(String[] args) {
        //启动
        new Myframe();
    }
}
class Myframe extends Frame{
    public Myframe(){
        TextField textField = new TextField();
        add(textField);
        //监听这个文本框输入的文字
        MyActionListener2 myActionListener2 = new MyActionListener2();
        //按下enter，就会触发这个输入框的事件
        textField.addActionListener(myActionListener2);
        //设置替换编码
        textField.setEchoChar('*');
        setVisible(true);
        pack();
    }
}
class MyActionListener2 implements ActionListener{
    @Override
    public void actionPerformed(ActionEvent e) {
        TextField field = (TextField) e.getSource();//获得一些资源,返回了一个对象
        System.out.println(field.getText());//获得输入框中的文本
        field.setText("");//null
    }
}

3.简易计算器，组合+内部类回顾复习

oop原则：组合大于继承

class A extends B{
//继承
}
class A{//组合
    public B b;
}

目前代码

package com.tian.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

//简易计算器
public class TestCalc {
    public static void main(String[] args) {
        new Calculator();
    }
}
//计算器类
class Calculator extends Frame{
    public Calculator() {
        //3个文本框
        TextField num1 = new TextField(10);//字符数
        TextField num2 = new TextField(10);//字符数
        TextField num3 = new TextField(20);//字符数
        //1个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener(num1,num2,num3));
        //1个标签
        Label label = new Label("+");
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);

        pack();
        setVisible(true);
    }
}
//监听器类
class MyCalculatorListener implements ActionListener{
    //获取三个变量
    private TextField num1,num2,num3;
    public MyCalculatorListener(TextField num1,TextField num2,TextField num3){
        this.num1 = num1;
        this.num2 = num2;
        this.num3 = num3;
    }
    @Override
    public void actionPerformed(ActionEvent e) {
        //1.获得加数和被加数
        int n1 = Integer.parseInt(num1.getText());
        int n2 = Integer.parseInt(num2.getText());
        //2.将这个值+法运算后，放到第三个框
        num3.setText(""+(n1+n2));
        //3.清除前两个框
        num1.setText("");
        num2.setText("");
    }
}

完全改造为面向对象写法

package com.tian.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

//简易计算器
public class TestCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    //属性
    TextField num1,num2,num3;
    //方法
    public void loadFrame(){
        num1=new TextField(10);//字符数
        num2=new TextField(10);//字符数
        num3=new TextField(20);//字符数
        Button button = new Button("=");
        Label label = new Label("+");
        button.addActionListener(new MyCalculatorListener(this));
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
}
//监听器类
class MyCalculatorListener implements ActionListener{
    //获取计算器这个对象，在一个类中组合另外一个类；
    Calculator calculator = null;
    public MyCalculatorListener(Calculator calculator){
       this.calculator = calculator;
    }
    @Override
    public void actionPerformed(ActionEvent e) {
        //1.获得加数和被加数
        //2.将这个值+法运算后，放到第三个框
        //3.清除前两个框
        int n1 = Integer.parseInt(calculator.num1.getText());
        int n2 = Integer.parseInt(calculator.num2.getText());
        calculator.num3.setText(""+(n1+n2));
        calculator.num1.setText("");
        calculator.num2.setText("");
    }
}

内部类：

• 更好的包装

package com.tian.lesson02;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

//简易计算器
public class TestCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    //属性
    TextField num1,num2,num3;
    //方法
    public void loadFrame(){
        num1=new TextField(10);//字符数
        num2=new TextField(10);//字符数
        num3=new TextField(20);//字符数
        Button button = new Button("=");
        Label label = new Label("+");
        button.addActionListener(new MyCalculatorListener());
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
    }
    //监听器类
    //内部类最大的好处，就是可以畅通无阻的访问外部的属性和方法！
    class MyCalculatorListener implements ActionListener{
        @Override
        public void actionPerformed(ActionEvent e) {
            //1.获得加数和被加数
            //2.将这个值+法运算后，放到第三个框
            //3.清除前两个框
            int n1 = Integer.parseInt(num1.getText());
            int n2 = Integer.parseInt(num2.getText());
            num3.setText(""+(n1+n2));
            num1.setText("");
            num2.setText("");
        }
    }
}

4.画笔

package com.tian.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);//实心圆
        g.setColor(Color.GREEN);
        g.fillRect(150,200,200,200);
        //养成习惯，画笔用完，将他还原成最初的颜色
    }
}

5.鼠标监听

目的：想要实现鼠标画画！

package com.tian.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;

//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，针对窗口
        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.BLUE);
            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();
            //这里我们点击的时候，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新画一遍
            frame.repaint();//刷新
        }
    }
}

6.窗口监听

package com.tian.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() {
        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) {
                        WindowFrame source = (WindowFrame) e.getSource();//就是玩玩，没有什么实际意思
                        source.setTitle("被激活了");//就是玩玩，没有什么实际意思
                        System.out.println("windowActivated");
                    }
                }
        );
    }
}

7.键盘监听

package com.tian.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) {
                //获得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");
                }
                //根据按下不同的操作，产生不同的结果
            }
        });
    }
}