GUI学习——day2

事件监听

当某个事件完成时，会做什么

如按下按钮，生成aaa

java 复制代码

package com.kuang.lesson02;

import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;

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);
    }

    //关闭窗口的事件
    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");
    }
}

一个监听器监听多个组件

java 复制代码

package com.kuang.lesson02;

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

public class TestActionEventTwo {
    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");

        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);

    }
static class MyMonitor implements ActionListener {
        @Override
    public void actionPerformed(ActionEvent e){

            System.out.println("按钮被点击了"+e.getActionCommand());

        }
}
}

java 复制代码

import javax.swing.*;        // Swing组件（Frame/Button等）
import java.awt.*;           // AWT基础类（BorderLayout等）
import java.awt.event.*;     // 事件处理相关（ActionEvent/ActionListener）

输入框TextField监听

java 复制代码

package com.kuang.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();//自适应
    }

}

class MyActionListener2 implements ActionListener {
    @Override
    public void actionPerformed(ActionEvent e){
        TextField field = (TextField)    e.getSource();//获得一些资源，返回的一个对象
        System.out.println(field.getText());//获得输入框的文本
        field.setText("");//null ""
    }

}

简易计算器，组合+内部类回顾复习！

oop原则里：组合，大于继承！

java 复制代码

package com.kuang.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();

    }
}

//计算机类
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 MyCalculatorListenter(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 MyCalculatorListenter implements ActionListener {

    //获取三个变量
    private TextField num1, num2, num3;
    public MyCalculatorListenter(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.将这个值进行加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

java 复制代码

package com.kuang.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();

    }
}

//计算机类
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);
    }

    public Calculator() {
    }
}

//监听器类
class MyCalculatorListenter implements ActionListener {

    //获取计算机这个对象,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.将这个值进行加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

java 复制代码

package com.kuang.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();

    }
}

//计算机类
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！
    private class MyCalculatorListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            // 1.获得加数和被加数
            // 2.将这个值进行加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("");

        }
    }
}