Flash AS3：构造函数必须是实例方法

Question

Hello guys i have a problem and no idea how to fix it :( Can someone tell me how to do it?

Constructor functions must be instance methods.

So here is my code:

package
{
    import com.coreyoneil.collision.CollisionList;
    import flash.events.Event;
    import flash.display.Sprite;    

    public class terrain extends Sprite
    {
        private var wheel:Ball;
        private var collisionList:CollisionList;
        private var speed:Number;

        private const GRAVITY:Number = .75;
        private const FRICTION:Number = .98;
        private const IMMOVABLE:Number = 10000;


        public function terrain():void
        {
            if(stage == null)
            {
                addEventListener(Event.ADDED_TO_STAGE, init, false, 0, true);
                addEventListener(Event.REMOVED_FROM_STAGE, clean, false, 0, true);
            }
            else
            {
                init();
            }
        }

        private function init(e:Event = null):void
        {
            collisionList = new CollisionList(terrain);

            wheel = new wheel(10);
            wheel.mass = IMMOVABLE * 2;
            addChild(wheel);
            collisionList.addItem(wheel);
            wheel.x = 30;
            wheel.y = 10;

            speed = 0;

            terrain.graphics.lineStyle(15);

            addEventListener(Event.ENTER_FRAME, updateScene);
        }


        private function updateScene(e:Event):void
        {           
            var collisions:Array = collisionList.checkCollisions();

            if(collisions.length)
            {
                var collision:Object = collisions[0];
                var angle:Number = collision.angle;
                var overlap:int = collision.overlapping.length;

                var sin:Number = Math.sin(angle);
                var cos:Number = Math.cos(angle);

                var vx0:Number = wheel.vx * cos + wheel.vy * sin;
                var vy0:Number = wheel.vy * cos - wheel.vx * sin;

                // Unlike the other examples, here I'm choosing to calculate the amount
                // of bounce based on the objects' masses, with a default mass of 10000 (IMMOVABLE)
                // being used for the drawing the wheel is colliding with.  As such, the only
                // real variable in play here is the current vector of the wheel.
                vx0 = ((wheel.mass - IMMOVABLE) * vx0) / (wheel.mass + IMMOVABLE);
                wheel.vx = vx0 * cos - vy0 * sin;
                wheel.vy = vy0 * cos + vx0 * sin;

                wheel.vx -= cos * overlap /wheel.radius;
                wheel.vy -= sin * overlap / wheel.radius;

                wheel.vx += speed;
            }
            trace("down");
            wheel.vy += GRAVITY;
            wheel.vy *= FRICTION;
            wheel.vx *= FRICTION;

            wheel.x += wheel.vx;
            wheel.y += wheel.vy;

            if(wheel.x > stage.stageWidth) wheel.x = stage.stageWidth;  
            if(wheel.x < 0) wheel.x = 0;                                    
            if(wheel.y > stage.stageHeight - (wheel.height >> 1)) 
            {
                wheel.y = 10;   
                wheel.x = 30;
                wheel.vx = wheel.vy = 0;
            }

        }

        private function clean(e:Event):void
        {
            removeEventListener(Event.ENTER_FRAME, updateScene);
        }




    }
    }

There are some comment in the code.. Just ignore it i have used example.

Answer 1

collisionList = new CollisionList(terrain);
terrain.graphics.lineStyle(15);

This is error 1026, also thrown if the constructor is static, private or in your case used as an identifier. Either use this.graphics instead of terrain.graphics or just graphics.etc (remove terrain) and also pass 'this' as parameter for 'CollisionList'.
(Unrelated: Also it's better to name classes starting with a capital "Terrain")