构造函数传参

利用构造函数传递参数

   public class Painter{
   //定义方法
   public void showFrame(){
       javax.swing.JFrame frame=new javax.swing.JFrame();
       frame.setSize(300,400);
       frame.setTitle("QQworld");
       frame.setLocationRelativeTo(null);
       //frame.setDefaultCloseOperation(3);
       java.awt.FlowLayout layout=new java.awt.FlowLayout();
       frame.setLayout(layout);
       frame.setVisible(true);
//获取窗体的画布对象
java.awt.Graphics g = frame.getGraphics();
       //创建鼠标事件监听器
       java.awt.event.MouseListener mymouselistener=new MyMouseListener(g);
       // 对窗体进行鼠标事件监听
       frame.addMouseListener(mymouselistener);
      
      
   }
   public static void main(String[]args){
       Painter QQ=new Painter();
       QQ.showFrame();
   }
}
//创建一个鼠标监听器对象
public class MyMouseListener implements java.awt.event.MouseListener{
       private int x1,x2,y1,y2;
       private java.awt.Graphics g;  
        //构造函数
       public MyMouseListener(java.awt.Graphics gr){
g = gr;
        }
            //实现接口类中的所有抽象方法
             public void mouseClicked(java.awt.event.MouseEvent e){
                  System.out.println("clicked");
             }
             public void mousePressed(java.awt.event.MouseEvent e){
                  System.out.println("pressed");
                  x1=e.getX();
                  y1=e.getY();
             }
             public void  mouseReleased(java.awt.event.MouseEvent e){
                  System.out.println("release");
                  x2=e.getX();
                  y2=e.getY();
  //画图
g.drawLine(x1,y1,x2,y2);
             }
             public void mouseEntered(java.awt.event.MouseEvent e){
                  System.out.println("entered");
             }
             public void mouseExited(java.awt.event.MouseEvent e){
                  System.out.println("Exited");
             }
      
}
//如上例
先把MyMouseListener(g)中的实参g传给MyMouseListener(java.awt.Graphics gr)中的形参gr
然后再把gr传给MyMouseListener类中的属性g

评论

1 楼 神奇的蛋定 2013-05-25  

标题党啊，还是希望你把参数的传递说的详细一点，还有斌哥教导，只要主要的代码就好