通过类块

Question

我正在尝试制作一款船游戏，但我遇到了让对手褪色的问题。

嗯，这些对手（如船只）有一个班级。在这个课程中，我做了一个间隔，让它的孩子飞到左边（在每个速度数字上改变X选择添加敌人的函数中的第四个参数（ addOpponent(opponentX, opponentY, opponentType, opponentVelocity)），当他们中的任何一个坐标X小于-25，必须通过 class 块自行删除。

package  {

import flash.display.*
import flash.display.MovieClip;
import flash.utils.setTimeout;
import flash.utils.setInterval;
import flash.utils.clearInterval;

public class opponentNave extends MovieClip {

    public function opponentNave(opponentVelocitySet) {
    var loopMoveClassicOpponentsNave:uint = setInterval(movingClassicOpponentNave, 58);

        function movingClassicOpponentNave() {
            if (x < -25) {
                clearInterval(loopMoveClassicOpponentsNave);
                this.parent.removeChild(this);
            } else {
                x -= opponentVelocitySet;
            }
        }
    }
}

}

我正在使用this.parent.removeChild(this)。当对手X小于-25时我得到一个错误，而那时我想要移除对手的孩子。

Answer 1

以下是我将如何重构:(参见代码注释）

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

    public class opponentNave extends MovieClip
    {
        //create a class scoped variable for the velocity
        private var velocitySet:Number;

        public function opponentNave(opponentVelocitySet)
        {
            //set the velocity var
            velocitySet = opponentVelocitySet;

            //wait for this object (opponentNave) to be added to the display before doing anything display oriented
            this.addEventListener(Event.ADDED_TO_STAGE, addedToStage, false, 0, true);

        }

        private function addedToStage(e:Event):void {
            //run a function every frame tick of the application's fps
            //this is best for things that are display oriented instead of time based ways like Timer or Intervals
            this.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
        }

        private function enterFrameHandler(e:Event):void
        {
            if (x < -25){
                if (this.parent) this.parent.removeChild(this);
                this.removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
            }
            else
            {
                x -= velocitySet;
            }
        }
    }
}