multilistener.java

我在学习JAVA的讲义

/*
 * 1.1 code.
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.*;

public class MultiListener extends Applet 
                           implements ActionListener {

    TextArea topTextArea;
    TextArea bottomTextArea;
    Button button1, button2;

    public void init() {
        Label l = null;
        GridBagLayout gridbag = new GridBagLayout();
        GridBagConstraints c = new GridBagConstraints();
        setLayout(gridbag);

        c.fill = GridBagConstraints.BOTH;
        c.gridwidth = GridBagConstraints.REMAINDER;
        l = new Label("多监听器听到的:");
        gridbag.setConstraints(l, c);
        add(l);

        c.weighty = 1.0;
        topTextArea = new TextArea(5, 20);
        topTextArea.setEditable(false);
        gridbag.setConstraints(topTextArea, c);
        add(topTextArea);

        c.weightx = 0.0;
        c.weighty = 0.0;
        l = new Label("偷听者听到的:");
        gridbag.setConstraints(l, c);
        add(l);

        c.weighty = 1.0;
        bottomTextArea = new TextArea(5, 20);
        bottomTextArea.setEditable(false);
        gridbag.setConstraints(bottomTextArea, c);
        add(bottomTextArea);

        c.weightx = 1.0;
        c.weighty = 0.0;
        c.gridwidth = 1;
        c.insets = new Insets(10, 10, 0, 10);
        button1 = new Button("啦 啦 啦");
        gridbag.setConstraints(button1, c);
        add(button1);

        c.gridwidth = GridBagConstraints.REMAINDER;
        button2 = new Button("你别说话!");
        gridbag.setConstraints(button2, c);
        add(button2);

        button1.addActionListener(this);
        button2.addActionListener(this);

        button2.addActionListener(new Eavesdropper(bottomTextArea));
    }

    public void actionPerformed(ActionEvent e) {
        topTextArea.append(e.getActionCommand() + "\n");
    }



public static void main(String[] args){

   Frame f = new Frame("Converter Applet/Application");
	f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
	        System.exit(0);
            }
        });


	MultiListener  m=new MultiListener( );
	m.init();
	
	f.add("Center", m);
   f.pack();        //Resizes the window to its natural size.
   f.setVisible(true);

	}	

}

class Eavesdropper implements ActionListener {
    TextArea myTextArea;
    public Eavesdropper(TextArea ta) {
        myTextArea = ta;
    }

    public void actionPerformed(ActionEvent e) {
        myTextArea.append(e.getActionCommand() + "\n");
    }
}