弹跳的小球

跳动小球

package 
{
	import flash.display.Sprite;
	import flash.display.MovieClip;
	import flash.events.Event;
	import flash.ui.Keyboard;
	import flash.events.KeyboardEvent;
	
	
	public class  main extends Sprite
	{
		
		public var ball:Sprite;
		public var border:Sprite;
		public var vy:Number = 0;
		public var g:Number = 0.9;
		
		public function main()
		{
			//stage.addEventListener(KeyboardEvent.KEY_DOWN,keyDownHandler);
			//stage.addEventListener(KeyboardEvent.KEY_UP,keyUpHandler);
			addEventListener(Event.ENTER_FRAME,frameHandler);
		}
		
		/*public function keyDownHandler(e:KeyboardEvent):void
		{
			//trace("键盘按下");
			switch(e.keyCode)
			{
				case Keyboard.LEFT:
					vx = -5;
					break;
				case Keyboard.RIGHT:
					vx = 5;
					break;
			}
		}
		
		public function keyUpHandler(e:KeyboardEvent):void
		{
			//trace("键盘抬起");
			switch(e.keyCode)
			{
				case Keyboard.LEFT:
					vx = 0;
					break;
				case Keyboard.RIGHT:
					vx = 0;
					break;
			}
		}*/
		public function frameHandler(e:Event):void
		{
			vy += g;
			ball.y += vy;
			//if (ball.y >= border.y-ball.height)
			if(ball.hitTestObject(border))
			{
				ball.y = border.y - ball.height;
				vy = -20;
			}
		}	
	}
	
}