testcounter.java

用java 来实现计数器的加一减一标签显示计数器值

import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;


public class TestCounter {

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		
		new CounterFrame("计数器");

	}

}
class CounterFrame extends Frame
{
	Button counterAdd;
	Button counterSub;
	Button counterClear;
	Label counterValue;
	Counter count=new Counter();
	CounterFrame(String title)
	{
		super(title);
		counterAdd=new Button("加一");
		counterSub=new Button("减一");
		counterClear=new Button("清零");
		counterValue=new Label("显示");	
		count=new Counter();
		setLayout(new FlowLayout());
		add(counterValue);
		add(counterAdd);
		add(counterSub);
		add(counterClear);
		CounterWork countWork=new CounterWork();
		counterAdd.addActionListener(countWork);
		counterSub.addActionListener(countWork);
		counterClear.addActionListener(countWork);
		addWindowListener(new HandleWin());
		setSize(300,200);
		setVisible(true);
	}
	class CounterWork implements ActionListener{
		
		public void actionPerformed(ActionEvent e) {	
			
			Object countWork;
			if(e.getActionCommand()=="加一")
			{
				count.increment();
				counterValue.setText(String.valueOf(count.getCounter()));
		    }
			else if(e.getActionCommand()=="减一")
			{
				count.decrement();
				counterValue.setText(String.valueOf(count.getCounter()));
			}
			else 
			{
				count.reset();
				counterValue.setText(String.valueOf(count.getCounter()));
			}
				
		

	}
	}
	class HandleWin extends WindowAdapter
	{
		public void windowClosing(WindowEvent e)
		{
			(e.getWindow()).dispose();
			System.exit(0);
		}
	}
}
class Counter {
	private int counterValue;
	Counter()
	{
		counterValue=0;
	}
	Counter(int number)
	{
		counterValue=number;
	}
	void increment()
	{
		counterValue++;
	}
	void decrement()
	{
		if(counterValue>0) counterValue--;
		else System.out.println("投影仪已全部出借，此次操作失败！");
	}
	void  setCounter(int number)
	{
		counterValue=number;
	}
	int getCounter()
	{
		return counterValue;
	}
	void reset()
	{
		counterValue=0;
	}
	
}