大家好，我是新手，想实现在屏幕上点击即可输入一个点，该怎么实现呢，谢谢了！

var color:uint=0xff0000;
var radius:int=10;
stage.addEventListener(MouseEvent.MOUSE_DOWN,stageMouseDown);
function stageMouseDown($ev:MouseEvent):void{
graphics.beginFill(color);
graphics.drawCircle(mouseX,mouseY,radius);
}