Java Swing（七）：鼠标事件MouseEvent

鼠标事件MouseEvent
可以给控件/界面添加鼠标事件有三种监听器：
1.addMouseListener 点击，按住，抬起，移入，移出
2.addMouseMotionListener 移动，拖动
3.addMouseWheelListener 鼠标滚轮转动
MouseListener接口下要覆盖五个方法：mouseClicked，mouseEntered，mouseExited，mousePressed，mouseReleased分别对应不同的鼠标事件。
对于鼠标事件MouseEvent的常用方法：
getX()/getY 获取当前点击位置的坐标（相对于界面）
getXOnScreen()/getYOnSreen() 获取当前点击位置的坐标（相对于屏幕）
getSource() 点击的控件
getButton() 左键/中建/右键
getClickCount() 单机/双击/三击
由于每次使用MouseListener接口都要重写五个方法，所以改用抽象类MouseAdapter，要用哪个就写哪个。

以mouseClicked为例代码：

root.addMouseListener(new MouseAdapter(){            
    @Override           
    public void mouseClicked(MouseEvent e){                
        if(e.getButton() == MouseEvent.BUTTON1) System.out.println("左键");                
        else if(e.getButton() == MouseEvent.BUTTON2) System.out.println("中键");                
        else if(e.getButton() == MouseEvent.BUTTON3) System.out.println("右键");
     
        int cc = e.getClickCount();                
        if(cc == 1) System.out.println("单机");                
        else if(cc == 2) System.out.println("双击");
     
        System.out.println("鼠标位置:" + e.getX() +  "," + e.getY());                
        System.out.println("------------");            
    }        
});

MouseWheelListener滚轮事件

例：

MouseWheelListener wheelListener = new MouseWheelListener(){            
    @Override           
    public void mouseWheelMoved(MouseWheelEvent e){                
        Image image = canvas.getImage();                
        int i;                
        for(i=0;i<buttons.size();i++){                    
            if(buttons.get(i).getImage()==image) break;                
        }                
        ThumbButton button = buttons.get(i);                
        if(e.getUnitsToScroll()>0){ //滚轮向下时e.getUnitsToScroll()大于0                    
            button = nextImage(i);                
        }else{ //滚轮向上时e.getUnitsToScroll()小于0                    
            button = lastImage(i);                
        }                
        setBlueBorder(button);            
    }        
};