FLex中AS实现地球轨迹运动

效果如图所示：

该运用中你可以使用键盘方向键来改变球的运动，用副键盘+ -键改变球大小！
 此例用到两个AS文件一个是Ball类,另一个是Roation类。

Ball.as

package AS3_Ball { import flash.display.Sprite; public class Ball extends Sprite { public var radius:Number; public var color:uint; public var vx:Number = 0; public var vy:Number = 0; public var drag:Boolean = false; public function Ball(radius:Number=40,color:uint=0xff0000) { this.radius = radius; this.color = color; init(); } private function init():void { graphics.beginFill(color); graphics.drawCircle(0,0,radius); graphics.endFill(); } } }

Roation.as:

package AS3_Ball { import flash.display.Sprite; import flash.events.Event; import flash.events.KeyboardEvent; import flash.ui.Keyboard; [SWF(backgroundColor="0x000000",width="700",height="300",frameRate="30")] public class Roation extends Sprite { private var flag:Boolean = true; private var _ball:Ball; //小球 private var _angerX:Number = 0; //x角度 private var _angerY:Number = 0; //y角度 private var _centerX:Number = 0; //X坐标 private var _centerY:Number = 0; //Y坐标 private var _rangeX:Number = 0; //X半径长度 private var _rangeY:Number = 0; //Y半径长度 private var _xspeed:Number = .05; //X轴速度 private var _yspeed:Number = .05; //Y轴速度 private var _xpos:Number; //lineTo X轴 private var _ypos:Number; //lineTo y轴 private var _pen:Number = .01; //轨迹大小 private var _speed:Number = .8 //方向键值增减 private var _nums:Number = 0; //统计次数 public function Roation() { init(); } private function init():void { for(var i:uint=0;i<500;i++) { var balls:Ball = new Ball(Math.random()*1,0xFFFFFF); balls.x = Math.random()*stage.stageWidth; balls.y = Math.random()*stage.stageHeight; addChild(balls); } _ball = new Ball(5,0x0000FF); //自行创建Ball类 var ball:Ball = new Ball(15); addChild(ball); //创建中间太阳 addChild(_ball); //创建 地球 _centerX = stage.stageWidth/2; _centerY = stage.stageHeight/2; ball.x = _centerX; ball.y = _centerY; graphics.lineStyle(1,0xCCCCCC,1); graphics.moveTo(_centerX,_centerY); addEventListener(Event.ENTER_FRAME,onEnterFrame); stage.addEventListener(KeyboardEvent.KEY_UP,onKeyUp); stage.addEventListener(KeyboardEvent.KEY_DOWN,onKeyDown); } private function onEnterFrame(event:Event):void { //2 PI也就是一圈,14 PI 也就是7圈 if(_angerX>Math.PI*13&&flag) { flag = false; } graphics.lineStyle(_pen,0xE7E7E7,1); _xpos = _ball.x = _centerX+Math.cos(_angerX)*_rangeX; _ypos = _ball.y = _centerY+Math.sin(_angerY)*_rangeY; _angerX += _xspeed; _angerY += _yspeed; //让开始作用于椭圆运行 if(flag) { _rangeX += 0.3; _rangeY += .08; } //用次数统计清图,即Keyboar.UP事件的清图等于多余 if(_nums>800) { graphics.clear(); _nums = 0; } _nums++; graphics.lineTo(_xpos,_ypos); } private function onKeyUp(event:KeyboardEvent):void { graphics.clear(); graphics.lineTo(_xpos,_ypos); } private function onKeyDown(event:KeyboardEvent):void { if(event.keyCode==Keyboard.LEFT) { _rangeY += -_speed; }else if(event.keyCode==Keyboard.RIGHT){ _rangeX += _speed; }else if(event.keyCode==Keyboard.UP){ _rangeX += -_speed; }else if(event.keyCode==Keyboard.DOWN){ _rangeY += _speed; }else if(event.keyCode==Keyboard.NUMPAD_ADD){ _ball.scaleX = _ball.scaleY += .1; }else if(event.keyCode==Keyboard.NUMPAD_SUBTRACT){ _ball.scaleX = _ball.scaleY -= .1; } } } }