事件处理

事件和事件源

事件类和事件监听接口

实例

TestActionListener

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import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;

public class TestActionListener extends JFrame implements ActionListener {
	public TestActionListener() {
		this.setBounds(100, 200, 100, 200);
		JButton btnOk = new JButton("打开");
		btnOk.addActionListener(this);
		this.getContentPane().add(btnOk);
	}

	public void actionPerformed(ActionEvent e) {
		JFileChooser fchooser = new JFileChooser(new File("."));
		if (fchooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) {
			File file = fchooser.getSelectedFile();
			try {
				BufferedReader fir = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
				String aline;
				while ((aline = fir.readLine()) != null) {
					System.out.println(aline);
				}
			} catch (Exception ex) {
				ex.printStackTrace();
			}
		}
	}

	public static void main(String[] args) {
		TestActionListener frame = new TestActionListener();
		frame.setVisible(true);
	}
}

TestActionEvent

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import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestActionEvent {
	public static void main(String args[]) {
		
		Frame f = new Frame("Test");
		Button b = new Button("Press Me!");
		
		//Monitor bh = new Monitor();
		
		b.addActionListener(new Monitor());
		
		
		f.add(b,BorderLayout.CENTER);
		
		f.pack();
		f.setVisible(true);
	}
}


class Monitor implements ActionListener {
	public void actionPerformed(ActionEvent e) {
        System.out.println("a button has been pressed");    
    }
}

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import java.awt.Button;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestActionEvent2 {
	
	public static void main(String args[]) {
		
		Frame f = new Frame("Test");
		Button b1 = new Button("Start");
		Button b2 = new Button("Stop");
		
		Monitor2 bh = new Monitor2();
		
		b1.addActionListener(bh);  
		
		b2.addActionListener(bh);
		
		//b2.setActionCommand("game over");
		
		f.add(b1,"North");
		
		f.add(b2,"Center");
		
		f.pack(); 
		
		f.setVisible(true);
	}
}

class Monitor2 implements ActionListener {
	
    public void actionPerformed(ActionEvent e) {
    	
    	System.out.println("a button has been pressed," + 
    	"the relative info is:\n " + e.getActionCommand());  
    	
    }
    
}