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java动画——鼠标事件
摘要: java动画——鼠标事件
java动画——鼠标事件
// 程序:处理鼠标事件
// 范例文件:HandleMouseEvent.java
import java.awt.*;
import java.applet.*;
import java.awt.event.*; //为了处理事件
//除了Runnable之外,还实现了MouseListener及MouseMotionListener
public class HandleMouseEvent extends Applet
implements Runnable,MouseListener,MouseMotionListener
{
int AppletWidth,AppletHeight,hammerX,hammerY,
hammerWidth,hammerHeight,clickCount;
Image hammer1,hammer2,OffScreen,currentHammer;
Thread newThread;
boolean showHammer;
Graphics drawOffScreen;
MediaTracker MT;
public void init()
{
addMouseListener(this); //注册事件处理方法
addMouseMotionListener(this);
setBackground(Color.gray); //设定背景颜色
AppletWidth = getSize().width; //取得Applet的高度
AppletHeight = getSize().height; //取得Applet的宽度
clickCount = 0; //mouseClick事件发生的次数
//取得铁锤图像
hammer1 = getImage(getDocumentBase(),"Images/hammer1.gif");
hammer2 = getImage(getDocumentBase(),"Images/hammer2.gif");
MT = new MediaTracker(this);
MT.addImage(hammer1,0);
MT.addImage(hammer2,0);
try
{
showStatus("图像加载中(Loading Images)...");
MT.waitForAll();
}
catch(InterruptedException E){ } //没有进行异常处理
hammerWidth = hammer1.getWidth(this); //取得铁锤图像宽度
hammerHeight = hammer1.getHeight(this); //取得铁锤图像高度
currentHammer = hammer1; //使用铁锤图像1
showHammer = false; //先不显示铁锤
//建立次画面
OffScreen = createImage(AppletWidth,AppletHeight);
drawOffScreen = OffScreen.getGraphics();
}
public void start() //start()方法
{
newThread = new Thread(this); //建立与启动新线程
newThread.start();
}
public void stop() //stop()方法
{
newThread = null; //将线程设为null
}
public void paint(Graphics g)
{
//清除次画面
drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);
//绘制铁锤图像
if(showHammer)
drawOffScreen.drawImage(currentHammer,hammerX,hammerY,this);
//将次画面贴到主画面中
g.drawImage(OffScreen,0,0,this);
}
public void update(Graphics g) //update()方法
{
paint(g); //只单纯调用paint()方法
}
public void run()
{
while(newThread != null) //动画循环
{
repaint(); //重新绘制图像
try
{
Thread.sleep(80); //暂停程序执行80毫秒
}
catch(InterruptedException E){ }//没有进行异常处理
}
}
//=====实现MouseListener界面
public void mouseExited(MouseEvent e) //鼠标离开Component
{
if(showHammer) showHammer = false; //不绘制铁锤
}
public void mouseClicked(MouseEvent e) //鼠标按键被按下后放开
{
showStatus("挥动铁锤" + (++clickCount) + "次");
}
public void mouseEntered(MouseEvent e) //鼠标进入Component
{
if(!showHammer) showHammer = true; //绘制铁锤
}
public void mousePressed(MouseEvent e) //鼠标按键被按下
{
currentHammer = hammer2; //绘制铁锤图像2
}
public void mouseReleased(MouseEvent e) //鼠标按键放开
{
currentHammer = hammer1; //绘制铁锤图像1
}
//=====实现MouseMotionListener界面==================================
public void mouseMoved(MouseEvent e) //鼠标移动时
{
//设定铁锤图像的坐标
hammerX = e.getX() - (hammerWidth / 2);
hammerY = e.getY() - (hammerHeight / 2);
//碰到边界时的状态
if(hammerX <= 0)
hammerX = 0;
if(hammerX >= (AppletWidth - hammerWidth))
hammerX = AppletWidth - hammerWidth;
if(hammerY <= 0)
hammerY = 0;
if(hammerY >= (AppletHeight - hammerHeight))
hammerY = AppletHeight - hammerHeight;
showStatus("(" + hammerX + "," + hammerY + ")");
}
public void mouseDragged(MouseEvent e) //鼠标拖曳时
{
//设定铁锤图像的坐标
hammerX = e.getX() - (hammerWidth / 2);
hammerY = e.getY() - (hammerHeight / 2);
//碰到边界时的状态
if(hammerX <= 0)
hammerX = 0;
if(hammerX >= (AppletWidth - hammerWidth))
hammerX = AppletWidth - hammerWidth;
if(hammerY <= 0)
hammerY = 0;
if(hammerY >= (AppletHeight - hammerHeight))
hammerY = AppletHeight - hammerHeight;
showStatus("(" + hammerX + "," + hammerY + ")");
}
}
对于鼠标事件的处理:
首先加载相应的类:
import java.awt.event.*; //为了处理事件除了Runnable之外,还实现了MouseListener及MouseMotionListener
然后在类的申明中继承自MouseListener及MouseMotionListener接口
public class HandleMouseEvent extends Applet
implements Runnable,MouseListener,MouseMotionListener
其次在类的初始化部分注册事件处理方法:
public void init()
{
addMouseListener(this); //注册事件处理方法
addMouseMotionListener(this);
最后,在代码中分别添加这两种事件的处理函数:
在MouseListener事件中包含
public void mouseExited(MouseEvent e) //鼠标离开Component
public void mouseClicked(MouseEvent e) //鼠标按键被按下后放开
public void mouseEntered(MouseEvent e) //鼠标进入Component
public void mousePressed(MouseEvent e) //鼠标按键被按下
public void mouseReleased(MouseEvent e) //鼠标按键放开
而MouseMotionListener事件包括处理函数:
public void mouseMoved(MouseEvent e) //鼠标移动时
public void mouseDragged(MouseEvent e) //鼠标拖曳时
当然也是不管你的程序中是否用到,都必须声明出来。