Java图形用户界面中,处理事件时所必须的步骤是:
1、创建接受响应的组件(控件)
2、实现相关事件监听接口
3、注册事件源的动作监听器
4、事件触发时的事件处理
相应的可以通过以下的集中方式来作出事件响应。
- <span style="font-size: 18px;">一、容器类监听
- 效果:单击窗体中的三个按钮,实现相应的相应时间。
- </span><pre class="java" name="code">import java.awt.*;
- import java.awt.event.*;
- import javax.swing.*;
- //声明 类时,添加“implements ActionListener”实现监听的接口,如果要对多种监听方式进行监听,则用逗号间隔开
- // 比如“implements ActionListener,KeyListener”
- class ButtonListener extends JFrame implements ActionListener{
- JButton ok, cancel,exit; //创建接受响应的组建,就是三个按钮
- public ButtonListener(String title){
- super(title);
- this.setLayout(new FlowLayout());
- ok = new JButton("确定");
- cancel = new JButton("返回");
- exit = new JButton("退出");
- //下面三个语句 为按钮分别 注册监听器
- ok.addActionListener(this);
- cancel.addActionListener(this);
- exit.addActionListener(this);
- getContentPane().add(ok);
- getContentPane().add(cancel);
- getContentPane().add(exit);
- }
- //完成 事件触发时的事件处理
- public void actionPerformed(ActionEvent e){
- if(e.getSource()==ok)
- System.out.println("确定");
- if(e.getSource()==cancel)
- System.out.println("返回");
- if(e.getSource()==exit)
- System.exit(0);;
- }
- public static void main(String args[]) {
- ButtonListener pd=new ButtonListener("ActionEvent Demo");
- pd.setSize(250,100);
- pd.setVisible(true);
- }
- }
- </pre><br>
- <br>
- <pre></pre>
- <p><span style="font-size: 18px;">二、监听类实现</span><br>
- <br>
- <pre style="margin: 4px 0px; font-size: 18px; background-color: rgb(240, 240, 240);" class="java" name="code"><span style="font-size: 18px;">效果:单击窗体中的三个按钮,实现相应的相应时间。
- </span></pre><p></p>
- <div><span style="font-size: 18px;"><br>
- </span></div>
- <pre style="font-size: 18px;" class="html" name="code">import java.awt.*;
- import java.awt.event.*;
- import javax.swing.*;
- class ButtonListener1 extends JFrame { //这里没有实现监听
- JButton ok, cancel,exit;
- public ButtonListener1(String title){
- super(title);
- this.setLayout(new FlowLayout());
- ok = new JButton("确定");
- cancel = new JButton("返回");
- exit = new JButton("退出");
- ok.addActionListener(new MyListener());
- cancel.addActionListener(new MyListener());;
- exit.addActionListener(new MyListener());;
- getContentPane().add(ok);
- getContentPane().add(cancel);
- getContentPane().add(exit);
- }
- public static void main(String args[]) {
- ButtonListener pd=new ButtonListener("ActionEvent Demo");
- pd.setSize(250,100);
- pd.setVisible(true);
- }
- }
- //监听动作事件
- class MyListener implements ActionListener{
- public void actionPerformed(ActionEvent e){
- if(e.getActionCommand()=="确定")
- System.out.println("确定");
- if(e.getActionCommand()=="返回")
- System.out.println("返回");
- if(e.getActionCommand()=="退出")
- System.exit(0);;
- }
- } </pre><br>
- <span style="font-size: 18px;">三、使用 AbstractAction类实现监听</span><br>
- <span style="font-size: 18px;"> 这个方法,我也没搞清,照着别人的例子做出来的<br>
- 效果:单击菜单,作出响应</span><br>
- <pre style="font-size: 18px;" class="java" name="code">import java.awt.BorderLayout;
- import java.awt.event.ActionEvent;
- import javax.swing.AbstractAction;
- import javax.swing.Action;
- import javax.swing.JFrame;
- import javax.swing.JMenu;
- import javax.swing.JMenuBar;
- import javax.swing.JMenuItem;
- import javax.swing.JOptionPane;
- //此类继承AbstractAction,必须实现actionPerformed()方法。
- class AbstractEvent extends AbstractAction{
- //private static final long serialVersionUID = 1L;
- AbstractEvent(){
- }
- public void actionPerformed(ActionEvent e){
- //弹出确认对话框
- if (e.getActionCommand()=="open"){
- JOptionPane.showMessageDialog(null, "打开");
- }else if (e.getActionCommand()=="close"){
- JOptionPane.showMessageDialog(null, "关闭");
- }else if (e.getActionCommand()=="run"){
- JOptionPane.showMessageDialog(null, "运行");
- }else if (e.getActionCommand()=="stop"){
- JOptionPane.showMessageDialog(null, "停止");
- }
- }
- }
- public class TestAbstractEvent {
- private static JMenuBar menubar;
- private static JFrame frame;
- //指定MenuEvent的具体处理程序是AbstractEvent类完成的。
- final Action MenuEvent=new AbstractEvent();
- public TestAbstractEvent(){
- frame=new JFrame("menu");
- frame.getContentPane().setLayout(new BorderLayout());
- menubar=new JMenuBar();
- JMenu menuFile=new JMenu("file");
- //实例化一个菜单项,并添加监听openAction,
- JMenuItem menuItemopen=new JMenuItem("open");
- menuItemopen.addActionListener(MenuEvent);
- JMenuItem menuItemclose=new JMenuItem("close");
- menuItemclose.addActionListener(MenuEvent);
- menuFile.add(menuItemopen);
- menuFile.add(menuItemclose);
- JMenu menuTool=new JMenu("tool");
- JMenuItem menuItemrun=new JMenuItem("run");
- menuItemrun.addActionListener(MenuEvent);
- JMenuItem menuItemstop=new JMenuItem("stop");
- menuItemstop.addActionListener(MenuEvent);
- menuTool.add(menuItemrun);
- menuTool.add(menuItemstop);
- menubar.add(menuFile);
- menubar.add(menuTool);
- menubar.setVisible(true);
- frame.add(menubar,BorderLayout.NORTH);
- frame.setSize(400,200);
- frame.setVisible(true);
- }
- public static void main(String[] args){
- new TestAbstractEvent();
- }
- }</pre><br>
- <span style="font-size: 18px;">四、</span><span style="font-size: 18px;"> AbstractAction类 + 反射 的方法<br>
- <span style="font-size: 18px;">这个方法,我也没搞清,照着别人的例子做出来的!<br>
- </span><br>
- 效果:单击工具栏的三个按钮,通过按钮的名称,反射得到 与按钮名称相同的类实现响应。<br>
- <br>
- </span><pre class="java" name="code">import java.awt.BorderLayout;
- import java.awt.event.ActionEvent;
- import javax.swing.*;
- class ViewAction extends AbstractAction{
- private String ActionName="";
- //private JFrame frame=null;
- private Action action=null;
- public ViewAction(){
- }
- public ViewAction(String ActionName){
- this.ActionName=ActionName;
- //this.frame=frame;
- }
- @Override
- public void actionPerformed(ActionEvent e) {
- Action action=getAction(this.ActionName);
- action.execute();
- }
- private Action getAction(String ActionName){
- try{
- if (this.action==null){
- Action action=(Action)Class.forName(ActionName).newInstance();
- this.action=action;
- }
- return this.action;
- }catch(Exception e){
- return null;
- }
- }
- }
- public class TestAE extends JFrame {
- public JToolBar bar=new JToolBar();
- String buttonName[]={"b1","b2","b3"};
- public TestAE(){
- super("事件");
- for (int i=0;i<buttonName.length;i++){
- ViewAction action=new ViewAction(buttonName[i]);
- JButton button=new JButton(buttonName[i]);
- button.addActionListener(action);
- bar.add(button);
- }
- this.getContentPane().add(bar,BorderLayout.NORTH);
- this.setSize(300, 200);
- this.setLocationRelativeTo(null);
- this.setVisible(true);
- }
- public static void main(String [] args){
- new TestAE();
- }
- }
- interface Action{
- void execute();
- }
- class b1 implements Action{
- public void execute(){
- JOptionPane.showMessageDialog(null, "单击了 b1");
- }
- }
- class b2 implements Action{
- public void execute(){
- JOptionPane.showMessageDialog(null, "单击了 b2");
- }
- }
- class b3 implements Action{
- public void execute(){
- JOptionPane.showMessageDialog(null, "单击了 b3");
- }
- }</pre><br>
- <br>
- <p></p>