1.创建一个 Ball 类：
package {
import flash.display.Sprite;
public class Ball extends Sprite {
  public var radius:Number;
  public var vx:Number = 0;
  public var vy:Number = 0;
  private var color:uint;
  public function Ball(R:Number = 30,Col:uint = 0xff0000) {
   radius = R;
   color = Col;
   graphics.beginFill(0xff0000);
   graphics.drawCircle(0,0,radius);
   graphics.endFill();
  }
}
}

2.ball 对象：var ball:Ball = new Ball();

[视频教程] <wbr>ActionScript <wbr>3.0 <wbr>体验试教学

3.将 ball 加入显示列表：addChild(ball);

4.创建类路径
编辑—> 参数首选项 —> ActionScript —>“ActionScript 3.0 设置”

2.Easing 与 Spring 公式应用

Easing ：
var easing:Number = 0.8;
var targetX:Number = 100;
ball.vx = (targetX – ball.x) * easing;
ball.x += ball.vx;

Spring：
var spring:Number = 0.8;
var targetX:Number = 100;
ball.vx += (targetX – ball.x) * spring;
ball.x += ball.vx;

3.Easing 效果文档类(EaseToMouse.as)：

package {
import flash.display.Sprite;
import flash.events.Event;
public class EaseToMouse extends Sprite {
  private var ball:Ball;
  private var easing:Number = 0.2;
  public function EaseToMouse() {
   init();
  }
  private function init():void {
   ball = new Ball();
   addChild(ball);
   addEventListener(Event.ENTER_FRAME, onEnterFrame);
  }
  private function onEnterFrame(event:Event):void {
   var vx:Number = (mouseX - ball.x) * easing;
   var vy:Number = (mouseY - ball.y) * easing;
   ball.x += vx;
   ball.y += vy;
  }
}
}

4.Spring 链效果文档类(ChainArray.as)：

package
{
import flash.display.Sprite;
import flash.events.Event;

public class ChainArray extends Sprite
{
  private var balls:Array;
  private var numBalls:Number = 5;
  private var spring:Number = 0.1;
  private var friction:Number = 0.8;
  private var gravity:Number = 5;

  public function ChainArray()
  {
   init();
  }

  private function init():void
  {
   balls = new Array();
   for(var i:uint = 0; i < numBalls; i++)
   {
    var ball:Ball = new Ball(20);
    addChild(ball);
    balls.push(ball);
   }
   addEventListener(Event.ENTER_FRAME, onEnterFrame);
  }

  private function onEnterFrame(event:Event):void
  {
   graphics.clear();
   graphics.lineStyle(1);
   graphics.moveTo(mouseX, mouseY);
   moveBall(balls[0], mouseX, mouseY);
   graphics.lineTo(balls[0].x, balls[0].y);

   for(var i:uint = 1; i < numBalls; i++)
   {
    var ballA:Ball = balls[i-1];
    var ballB:Ball = balls[i];
    moveBall(ballB, ballA.x, ballA.y);
    graphics.lineTo(ballB.x, ballB.y);
   }
  }

  private function moveBall(ball:Ball, targetX:Number, targetY:Number):void
  {
   ball.vx += (targetX - ball.x) * spring;
   ball.vy += (targetY - ball.y) * spring;
   ball.vy += gravity;
   ball.vx *= friction;
   ball.vy *= friction;
   ball.x += ball.vx;
   ball.y += ball.vy;
  }
}
}