Summary of common event response method examples in Java

The examples in this article summarize common event response methods in Java, including container class monitoring, listener class, AbstractAction, reflection, etc. For your reference. The specific method is as follows:

First, in the Java graphical user interface, the necessary steps when processing events are:

1. Create a component (control) that accepts the response
2. Implementation Relevant event listening interface
3. Registering the action listener of the event source
4. Event processing when the event is triggered

Accordingly, the event response can be made through the following centralized method.

1. Container class monitoring

Effect: Click the three buttons in the form to achieve the corresponding response time.

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); 
 } 
}

2. Monitoring class implementation

Effect: Click three buttons in the form to achieve the corresponding corresponding time.

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);; 
  } 
}

3. Use the AbstractAction class to implement monitoring

Effect: click the menu and respond

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(); 
  } 
}

4. AbstractAction class + reflection method

Effect : Click three buttons on the toolbar, and through the name of the button, the response will be obtained by reflection using a class with the same name as the button.

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"); 
  } 
}

The above examples have more detailed comments and should not be difficult to understand. I hope the examples described in this article will be helpful to everyone.

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