checkboxexample.java

Java程序设计清华出版课件源码答案共十四章

import java.awt.*;
import java.awt.event.*;
class CheckboxExample
	extends WindowAdapter
		implements ItemListener {
	Frame f;
	Panel p;
	Checkbox one,two,three;
	TextField tf;

	public static void main(String args[]) {
		CheckboxExample ce = new CheckboxExample( );
		ce.go( );
	}

	public void go( ) {
		f = new Frame("Checkbox Example");
		p = new Panel( );

		//  创建三个复选框
		one = new Checkbox("One");
		two = new Checkbox("Two");
		three = new Checkbox("Three");

		//  注册事件监听程序
		one.addItemListener(this);
		two.addItemListener(this);
		three.addItemListener(this);

		p.add(one);
		p.add(two);
		p.add(three);
		f.add(p,"Center");

		tf = new TextField( );
		f.add(tf,"South");

		//  注册事件监听程序
		f.addWindowListener(this);
		f.setSize(300,150);
		f.setVisible(true);
	}

	//  实现ItemListener接口中的itemStateChanged( )方法
	public void itemStateChanged(ItemEvent e) {
		String state = "deselected";
		String st ;

		if (e.getStateChange( ) == ItemEvent.SELECTED) {
		state = "selected";
		}
		st = e.getItem( ) +" "+state;
		tf.setText(st);
	}

	//  覆盖WindowAdapter类中的windowClosing( )方法
	public void windowClosing(WindowEvent e){
		//  结束程序运行
		System.exit(0);
	}
}