java新手笔记27 监听器类

时间：2021-06-03 20:12:30

1、外部类监听

package com.yfs.javase;

import java.awt.Button;

import java.awt.FlowLayout;

import java.awt.Frame;

import java.awt.TextField;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

//外部类监听

public class FrameDemo1 extends Frame {

	Button but1 = new Button(" + ");

	Button but2 = new Button(" - ");

	TextField text = new TextField(20);

	public FrameDemo1() {

		super("event1外部类");

		setLocation(200, 150);

		// 设置布局

		setLayout(new FlowLayout());

		text.setText("100");

		text.setEditable(false);

		//创建监听器对象

		MyListener listener = new MyListener(this);

		//建立关联  监听器添加到按钮

		but1.addActionListener(listener);

		but2.addActionListener(listener);

		//text.getText();//取text值

		add(but1);

		add(text);

		add(but2);

		setResizable(false);

        pack();

		// 默认隐藏 设置显示

		setVisible(true);

	}

	public static void main(String[] args) {

			new FrameDemo1();

	}

}

//开发监听器  实现监听器接口

class MyListener implements ActionListener {

	private FrameDemo1 frame;

	//通过构造方法强制传入窗体对象

	public MyListener(FrameDemo1 frame) {

		this.frame = frame;

	}

   //ActionEvent  事件对象

	@Override

	public void actionPerformed(ActionEvent e) {

//		System.out.println("按钮被单击了....");

//		//事件对象

		System.out.println(e.getActionCommand());//控件字符

//		System.out.println(e.getSource());//事件源

		//从text取值

		//依赖传入对象

		//FrameDemo1 frame = new FrameDemo1();//不能创建窗体对象

		int val = Integer.parseInt(frame.text.getText());

		System.out.println("val =  " + val);

		String opt = e.getActionCommand().trim();

		if("+".equals(opt)){

			frame.text.setText(String.valueOf(val + 1));

		} else if("-".equals(opt)){

			frame.text.setText(String.valueOf(val - 1));

		} 

	}

}

2.内部类监听

package com.yfs.javase;

import java.awt.Button;

import java.awt.FlowLayout;

import java.awt.Frame;

import java.awt.TextField;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

//内部类监听

public class FrameDemo2 extends Frame {

	Button but1 = new Button(" + ");

	Button but2 = new Button(" - ");

	TextField text = new TextField(20);

	public FrameDemo2() {

		super("event1内部类");

		setLocation(200, 150);

		// 设置布局

		setLayout(new FlowLayout());

		text.setText("100");

		text.setEditable(false);

		//创建监听器对象

		Listener listener = new Listener();

		//建立关联  监听器添加到按钮

		but1.addActionListener(listener);

		but2.addActionListener(listener);

		//text.getText();//取text值

		add(but1);

		add(text);

		add(but2);

		setResizable(false);

        pack();

		// 默认隐藏 设置显示

		setVisible(true);

	}

	//内部类

	class Listener implements ActionListener {

		@Override

		public void actionPerformed(ActionEvent e) {

			int val = Integer.parseInt(text.getText());

			String opt = e.getActionCommand().trim();

			System.out.println(opt);

			if("+".equals(opt)){

				text.setText(String.valueOf(val + 1));

			} else if("-".equals(opt)){

				text.setText(String.valueOf(val - 1));

			}

		}

	}

	public static void main(String[] args) {

			new FrameDemo2();

	}

}

3.自监听

package com.yfs.javase;

import java.awt.Button;

import java.awt.FlowLayout;

import java.awt.Frame;

import java.awt.TextField;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

//自监听

public class FrameDemo3 extends Frame implements ActionListener {

	Button but1 = new Button(" + ");

	Button but2 = new Button(" - ");

	TextField text = new TextField(20);

	public FrameDemo3() {

		super("event1自监听类");

		setLocation(200, 150);

		// 设置布局

		setLayout(new FlowLayout());

		text.setText("100");

		text.setEditable(false);

		//建立关联  监听器添加到按钮

		but1.addActionListener(this);

		but2.addActionListener(this);

		//text.getText();//取text值

		add(but1);

		add(text);

		add(but2);

		setResizable(false);

        pack();

		// 默认隐藏 设置显示

		setVisible(true);

	}

	public static void main(String[] args) {

			new FrameDemo3();

	}

	@Override

	public void actionPerformed(ActionEvent e) {

		//事件处理代码

		int val = Integer.parseInt(text.getText());

		String opt = e.getActionCommand().trim();

		if("+".equals(opt)){

			text.setText(String.valueOf(val + 1));

		} else if("-".equals(opt)){

			text.setText(String.valueOf(val - 1));

		}

	}

}

4.匿名类监听

package com.yfs.javase;

import java.awt.Button;

import java.awt.FlowLayout;

import java.awt.Frame;

import java.awt.TextField;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

//匿名类监听

public class FrameDemo4 extends Frame {

	Button but1 = new Button(" + ");

	Button but2 = new Button(" - ");

	TextField text = new TextField(20);

	public FrameDemo4() {

		super("event1匿名监听类");

		setLocation(200, 150);

		// 设置布局

		setLayout(new FlowLayout());

		text.setText("100");

		text.setEditable(false);

		//建立关联  监听器添加到按钮

		but1.addActionListener(new ActionListener() {

			@Override

			public void actionPerformed(ActionEvent arg0) {

				int val = Integer.parseInt(text.getText()) + 1;

				text.setText(String.valueOf(val));

			}

		});

		but2.addActionListener(new ActionListener() {

			@Override

			public void actionPerformed(ActionEvent arg0) {

				int val = Integer.parseInt(text.getText()) - 1;

				text.setText(String.valueOf(val));

			}

		});

		//text.getText();//取text值

		add(but1);

		add(text);

		add(but2);

		setResizable(false);

        pack();

		// 默认隐藏 设置显示

		setVisible(true);

	}

	public static void main(String[] args) {

			new FrameDemo4();

	}

}

5.背景图片

package com.yfs.javase;

import java.awt.FlowLayout;

import java.awt.Image;

import javax.swing.Icon;

import javax.swing.ImageIcon;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

//匿名类监听

public class FrameDemo5 extends JFrame {

	public FrameDemo5() {

		super("event1匿名监听类");

		setBounds(200, 150, 400, 400);

		setLayout(new FlowLayout());

		//标题图片

		Image logo = new ImageIcon("img/m.gif").getImage();

		setIconImage(logo);

		//图片label

		Icon ic = new ImageIcon("img\\index.gif");

		JLabel jl = new JLabel(ic);

		JButton but = new JButton(new ImageIcon("img/1_03.gif"));

		add(but);

		add(jl);

		setResizable(false);

        //pack();

		setVisible(true);

	}

	public static void main(String[] args) {

			new FrameDemo5();

	}

}

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