actionscript-3 - 为什么我不能从其他类访问公共(public)变量？

Question

我想在我的游戏文档类中定义我的变量，然后在我的 Movement 类中使用其中的一些变量。然而，当我在我的运动类中使用这些变量时，我收到大量编译错误，说它们都是未定义的。

因此我的问题是，为什么我的公共(public)变量没有传递给我的其他类？我通过 import game; 导入了这个类，所以这让我很困惑。我可能只是做错了，但非常感谢您的帮助。

时间线

addChild((new Movement));

游戏文档类

package 
{
    import flash.display.MovieClip;
    import flash.utils.Timer;
    import flash.events.TimerEvent;

    public class game extends MovieClip
    {
        public var area1:Boolean = true;
        public var area2:Boolean = false;
        public var area3:Boolean = false;

        public var player1:Boolean = true;

        public var playerPosKeeper_mc:MovieClip = new mc_PlayerPosKeeper();

        public var up_dpad:MovieClip = new dpad_Up();
        public var down_dpad:MovieClip = new dpad_Down();
        public var left_dpad:MovieClip = new dpad_Left();
        public var right_dpad:MovieClip = new dpad_Right();
        public var menu_dpad:MovieClip = new dpad_Menu();
        public var run_dpad:MovieClip = new dpad_Menu();

        public var barrierRoof1_game:MovieClip = new game_BarrierRoof();
        public var barrierRoof2_game:MovieClip = new game_BarrierRoof();
        public var barrierSide1_game:MovieClip = new game_BarrierSide();
        public var barrierSide2_game:MovieClip = new game_BarrierSide();

        public function game()
        {
            trace("SUCCESS | Constructed Game Class");

        }
    }
}

运动类

package 
{
    import game;
    import flash.display.Stage;
    import flash.display.MovieClip;
    import flash.events.Event;
    import flash.events.TouchEvent;
    import flash.net.dns.AAAARecord;
    import flash.ui.Multitouch;
    import flash.ui.MultitouchInputMode;


    public class Movement extends MovieClip
    {
        var inMotion:Boolean = false;

        public function Movement()
        {
            trace("SUCCESS | Constructed Movement Class");

            addChild(playerPosKeeper_mc);
            playerPosKeeper_mc.x = 384;
            playerPosKeeper_mc.y = 46;

            addChild(up_dpad);
            up_dpad.x = 55;
            up_dpad.y = 336;

            addChild(down_dpad);
            down_dpad.x = 57;
            down_dpad.y = 432;

            addChild(left_dpad);
            left_dpad.x = 19;
            left_dpad.y = 372;

            addChild(right_dpad);
            right_dpad.x = 118;
            right_dpad.y = 372;

            addChild(menu_dpad);
            menu_dpad.x = 61;
            menu_dpad.y = 377;

            addChild(run_dpad);
            run_dpad.x = 684;
            run_dpad.y = 369;

            addChild(barrierRoof1_game);
            barrierRoof1_game.x = 0;
            barrierRoof1_game.y = 0;

            addChild(barrierRoof2_game);
            barrierRoof2_game.x = 0;
            barrierRoof2_game.y = 470;

            addChild(barrierSide1_game);
            barrierSide1_game.x = 0;
            barrierSide1_game.y = 0;

            addChild(barrierSide2_game);
            barrierSide2_game.x = 790;
            barrierSide2_game.y = 0;

            Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;

            up_dpad.addEventListener(TouchEvent.TOUCH_BEGIN, moveUpTouchBEGIN);
            up_dpad.addEventListener(TouchEvent.TOUCH_END, moveUpTouchEND);

        }
        public function moveUpTouchBEGIN(e:TouchEvent):void
        {
            trace("Touch Began")
        }

        public function moveUpTouchEND(e:TouchEvent):void
        {
            trace("Touch Ended")
        }
    }

}

Answer 1

您感到困惑，因为“公共(public)”并不意味着“全局”。将变量声明为公共(public)变量意味着您希望向任何实体授予对它的访问权限，前提是该实体知道该变量的位置。

让我们看看你有什么。

• 顶部显示对象:舞台。
• 主要时间轴:游戏是舞台的 child 。
• MovieClips up_dpad、down_dpad等，都是游戏实例的字段。
• 运动:实例是游戏的 child 。

在 Movement 中，您尝试访问 up_dpad 和其他内容，但它们被保留为游戏实例的字段，与 Movement 实例无关。这就是为什么它们不在 Movement 的寻址范围内。

因此，如果您想将这些变量声明为游戏字段，则需要以正确的方式从 Movement 中对它们进行寻址。

忘记时间表。在游戏中(出于缘故，除非在 Guzzle 下，否则永远不要用小写字母调用类)，我相信这是一个根文档类:

    public function Game()
    {
        trace("SUCCESS | Constructed Game Class");

        // Pass reference to this instance to the constructor.
        var aMove:Movement = new Movement(this);

        // Add it as a child.
        addChild(aMove);
    }

在运动中:

    public function Movement(main:Game)
    {
        trace("SUCCESS | Constructed Movement Class");

        // Access variables inside Game instance via given reference.
        addChild(main.playerPosKeeper_mc);
        main.playerPosKeeper_mc.x = 384;
        main.playerPosKeeper_mc.y = 46;

        // ...and so on
    }

这些是面向对象编程的基础知识。如果您想访问对象内部的任何内容，您需要先访问该对象。