6.7.2画板事件

　　你可以覆盖一般的事件处理成员函数。下面是一个包含了mouseDown事件处理的例子：importjava.awt.*;importjava.applet.Applet;

　　publicclasscanvasextendsApplet{

　　Buttonb1;

　　publicvoidinit(){//SetourlayoutasaBorderstylesetLayout(new

　　BorderLayout(15,15));b1=newButton(\"Test\");myCanvasc1=new

　　myCanvas(100,100);//addthecanvasandthebuttontotheapplet

　　add(\"Center\",c1);add(\"South\",b1);}

　　publicbooleanaction(Evente,Objectarg){System.out.println(\"Event:

　　\"+arg);returntrue;}

　　publicbooleanmouseDown(Evente,intx,inty)

　　{System.out.println(\"Mouseworks:(\"+x+\",\"+y+\")\");returntrue;}}

　　classmyCanvasextendsCanvas{privateintwidth;privateintheight;

　　publicmyCanvas(intw,inth){width=w;height=h;reshape(0,0,w,

　　h);}

　　publicvoidpaint(Graphicsg){g.setColor(Color.blue);g.fillRect(0,0,

　　width,height);}

　　publicbooleanmouseDown(Evente,intx,inty){if((x