movebtn.java

java练习程序

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class MoveBtn extends Applet implements KeyListener
{
	Button b=new Button("我能被移动");
	int b_x=0, b_y=0;
	public void init()
	{
		b.addKeyListener(this);//按钮获得键盘事件监视器
		setLayout(null);
		add(b);
		b.setBounds(20, 20, 70, 30);
		b_x=b.getBounds().x;b_y=b.getBounds().y;////获取按钮左上角的x，y坐标
	}
	public void keyTyped(KeyEvent e)
	{}
	
	public void keyPressed(KeyEvent e)
	{
		if(e.getKeyCode()==KeyEvent.VK_UP)
		{
			b_y=b_y-2;
			if(b_y<=0)
			{
				b_y=0;
			}
			b.setLocation(b_x, b_y);
		}
		else if(e.getKeyCode()==KeyEvent.VK_DOWN)
		{
			b_y=b_y+2;
			if(b_y>=300) b_y=300;
			b.setLocation(b_x, b_y);
		}
		else if(e.getKeyCode()==KeyEvent.VK_LEFT)
		{
			b_x=b_x- 2;
			if(b_x<=0)b_x=0;
			b.setLocation(b_x, b_y);
		}
		else if(e.getKeyCode()==KeyEvent.VK_RIGHT)
		{
			b_x=b_x+2;
			if(b_x>=300) b_x=300;
			b.setLocation(b_x, b_y);
		}
	}
	
	public void keyReleased(KeyEvent e)
	{}
}