GUI编程核心技术AWT——事件监听

一个按钮的事件监听

package com.wei.lesson02;

import java.awt.*;
import java.awt.event.*;

//一个按钮的事件监听
public class TestActionEvent {
public static void main(String[] args) {

Frame frame = new Frame();

Button button = new Button("btn");

MyActionListener myActionListener = new MyActionListener();

//按钮监听事件
button.addActionListener(myActionListener);

frame.add(button, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
windowClose(frame);

}
//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);
}
});
}
}
class MyActionListener implements ActionListener {
//监听事件，当某个事件发生时，将要干什么
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("aaa");//按下按钮时，将会输出这个指令

}

}

多个按钮共享一个监听事件

package com.wei.lesson02;

import java.awt.*;
import java.awt.event.*;

public class TestAction2 {
public static void main(String[] args) {
//多个按钮实现同一个监听事件
//如果按下start按钮实现一个操作，按下stop按钮实现另一个操作

Frame frame = new Frame();

Button button1 = new Button("start");
Button button2= new Button("stop");
Button button3= new Button("sleep");

frame.add(button1,BorderLayout.EAST);
frame.add(button2,BorderLayout.WEST);
frame.add(button3,BorderLayout.CENTER);

//给按钮设置一下信息,下面通过e可以拿到
//如果没设置信息，则默认的输出按钮上的lable
button1.setActionCommand("button1-start");
button2.setActionCommand("button2-stop");
button3.setActionCommand("啥也不干");

MyMonitor myMonitor = new MyMonitor();

button1.addActionListener(myMonitor);
button2.addActionListener(myMonitor);
button3.addActionListener(myMonitor);

frame.setVisible(true);
frame.pack();
windowClose(frame);

}
private static void windowClose(Frame frame){

frame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
}//监听类
class MyMonitor implements ActionListener{
@Override//实现了接口就要重写里面的方法
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());
//在这里也可以加些判断，比如点击的是某个按钮，将会实现什么操作
if()...

}
}