Java自学-图形界面 事件监听

时间:2024-07-29 11:36:38

Swing 如何进行事件监听

示例 1 : 按钮监听

创建一个匿名类实现ActionListener接口,当按钮被点击时,actionPerformed方法就会被调用

Java自学-图形界面 事件监听

package gui;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener; import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel; public class TestGUI {
public static void main(String[] args) { JFrame f = new JFrame("LoL");
f.setSize(400, 300);
f.setLocation(580, 200);
f.setLayout(null); final JLabel l = new JLabel(); ImageIcon i = new ImageIcon("e:/project/j2se/shana.png");
l.setIcon(i);
l.setBounds(50, 50, i.getIconWidth(), i.getIconHeight()); JButton b = new JButton("隐藏图片");
b.setBounds(150, 200, 100, 30); // 给按钮 增加 监听
b.addActionListener(new ActionListener() { // 当按钮被点击时,就会触发 ActionEvent事件
// actionPerformed 方法就会被执行
public void actionPerformed(ActionEvent e) {
l.setVisible(false);
}
}); f.add(l);
f.add(b);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true);
}
}

示例 2 : 键盘监听

键盘监听器: KeyListener

keyPressed 代表 键被按下

keyReleased 代表 键被弹起

keyTyped 代表 一个按下弹起的组合动作

KeyEvent.getKeyCode() 可以获取当前点下了哪个键

Java自学-图形界面 事件监听

package gui;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener; import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel; public class TestGUI {
public static void main(String[] args) { JFrame f = new JFrame("LoL");
f.setSize(400, 300);
f.setLocation(580, 200);
f.setLayout(null); final JLabel l = new JLabel(); ImageIcon i = new ImageIcon("e:/project/j2se/shana.png");
l.setIcon(i);
l.setBounds(50, 50, i.getIconWidth(), i.getIconHeight()); // 增加键盘监听
f.addKeyListener(new KeyListener() { // 键被弹起
public void keyReleased(KeyEvent e) { // 39代表按下了 “右键”
if (e.getKeyCode() == 39) {
// 图片向右移动 (y坐标不变,x坐标增加)
l.setLocation(l.getX() + 10, l.getY());
}
} //键被按下
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub } // 一个按下弹起的组合动作
public void keyTyped(KeyEvent e) { }
}); f.add(l); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true);
}
}

示例 3 : 鼠标监听

MouseListener 鼠标监听器

mouseReleased 鼠标释放

mousePressed 鼠标按下

mouseExited 鼠标退出

mouseEntered 鼠标进入

mouseClicked 鼠标点击

在本例中,使用mouseEntered,当鼠标进入图片的时候,图片就移动位置

Java自学-图形界面 事件监听

package gui;

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random; import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel; public class TestGUI {
public static void main(String[] args) { final JFrame f = new JFrame("LoL");
f.setSize(800, 600);
f.setLocationRelativeTo(null);
f.setLayout(null); final JLabel l = new JLabel();
ImageIcon i = new ImageIcon("e:/project/j2se/shana_heiheihei.png");
l.setIcon(i);
l.setBounds(375, 275, i.getIconWidth(), i.getIconHeight()); f.add(l); l.addMouseListener(new MouseListener() { // 释放鼠标
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub } // 按下鼠标
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub } // 鼠标退出
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub } // 鼠标进入
public void mouseEntered(MouseEvent e) { Random r = new Random(); int x = r.nextInt(f.getWidth() - l.getWidth());
int y = r.nextInt(f.getHeight() - l.getHeight()); l.setLocation(x, y); } // 按下释放组合动作为点击鼠标
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub }
}); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true);
}
}

示例 4 : 适配器

MouseAdapter 鼠标监听适配器

一般说来在写监听器的时候,会实现MouseListener。

但是MouseListener里面有很多方法实际上都没有用到,比如mouseReleased ,mousePressed,mouseExited等等。

这个时候就可以使用 鼠标监听适配器,MouseAdapter 只需要重写必要的方法即可

package gui;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random; import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel; public class TestGUI {
public static void main(String[] args) { final JFrame f = new JFrame("LoL");
f.setSize(800, 600);
f.setLocationRelativeTo(null);
f.setLayout(null); final JLabel l = new JLabel(""); ImageIcon i = new ImageIcon("e:/project/j2se/shana_heiheihei.png");
l.setIcon(i);
l.setBounds(375, 275, i.getIconWidth(), i.getIconHeight()); f.add(l); // MouseAdapter 适配器,只需要重写用到的方法,没有用到的就不用写了
l.addMouseListener(new MouseAdapter() { // 只有mouseEntered用到了
public void mouseEntered(MouseEvent e) { Random r = new Random(); int x = r.nextInt(f.getWidth() - l.getWidth());
int y = r.nextInt(f.getHeight() - l.getHeight()); l.setLocation(x, y); }
}); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true);
}
}

更多内容,点击了解: Swing 如何进行事件监听