Question

在我的游戏中，如果球击中了winBox，你会收到一条Win消息。问题是球反弹，并可能反复击中盒子。如何防止每个会话发生两次消息？

            if (simContacts.isCurrentContact(winBox,gameBall))
        {
            // Won.
            trace ('You won!');
            isFiring=false;

            //Win Message
            winMsg=new win_mc();
            addChild(winMsg);
            winMsg.y=250;
            winMsg.x=40;
            winMsg.gotoAndPlay(2);

        }

完整代码：

package  {

import flash.display.MovieClip;
import com.actionsnippet.qbox.*;  
import flash.events.MouseEvent;
import flash.events.Event;

[SWF(width = 300, height = 600, frameRate = 60)]  

public class LuckyHitBeta extends MovieClip {

    public var sim:QuickBox2D;
    var winBox:QuickObject;
    var looseBox:QuickObject;
    var looseBox2:QuickObject;
    var gameBall:QuickObject;
    var simContacts:QuickContacts;
    var isFiring:Boolean=false;
    var ballIcon:ballIcon_mc;
    var winMsg:win_mc;



    /**
     * Constructor
     */
    public function LuckyHitBeta()
    {   
        liveIcon();
        sim = new QuickBox2D(this);
        simContacts = sim.addContactListener();
        simContacts.addEventListener(QuickContacts.ADD, contactListener);
        //Important Collisions;

        winBox = sim.addBox({x:2,y:597/30, width:98/30, height:10/30, density:0, skin:stick, skinScale:false});
        looseBox = sim.addBox({x:5,y:597/30, width:98/30, height:10/30, density:0, skin:stick, skinScale:false});
        looseBox2 = sim.addBox({x:8,y:597/30, width:98/30, height:10/30, density:0, skin:stick, skinScale:false});
        //Collisions
        sim.addBox({x:3.5,y:560/30, width:72/30, height:13/30, density:0, skin:stick, skinScale:false, angle:1.57});
        sim.addBox({x:6.5,y:560/30, width:72/30, height:13/30, density:0, skin:stick, skinScale:false, angle:1.57});
        sim.addBox({x:0/30,y:300/30, width:600/30, height:28/30, density:0, skin:stick, skinScale:false, angle:1.57});
        sim.addBox({x:300/30,y:300/30, width:600/30, height:28/30, density:0, skin:stick, skinScale:false, angle:1.57});



        // make obstacles 
        for (var i:int = 0; i<(stage.stageWidth/28); i++){ 
        //End
             sim.addCircle({x:1.2 + i * 0.8, y:16, radius:0.15, density:0, skin:ping, scaleSkin:false});
             sim.addCircle({x:0.6 + i * 0.8, y:15, radius:0.15, density:0, skin:ping, scaleSkin:false});
        }

        for (var o:int = 0; o<(stage.stageWidth/55); o++){  
        //Middle

              sim.addCircle({x:1.3 + o * 1.5, y:14, radius:0.15, density:0, skin:ping, scaleSkin:false});
              sim.addCircle({x:1.3 + o * 1.5, y:13, radius:0.15, density:0, skin:ping, scaleSkin:false});
              sim.addCircle({x:1.3 + o * 1.5, y:12, radius:0.15, density:0, skin:ping, scaleSkin:false});
              sim.addCircle({x:1.3 + o * 1.5, y:11, radius:0.15, density:0, skin:ping, scaleSkin:false});
              sim.addCircle({x:1.3 + o * 1.5, y:10, radius:0.15, density:0, skin:ping, scaleSkin:false});
        }

        for (var u:int = 0; u<(stage.stageWidth/45); u++){    
        //Start
             sim.addCircle({x:0.8 + u * 1.3, y:09, radius:0.15, density:0, skin:ping, scaleSkin:false});
             sim.addCircle({x:1.55 + u * 1.3, y:08, radius:0.15, density:0, skin:ping, scaleSkin:false});
             sim.addCircle({x:0.8 + u * 1.3, y:07, radius:0.15, density:0, skin:ping, scaleSkin:false});
             sim.addCircle({x:1.55 + u * 1.3, y:06, radius:0.15, density:0, skin:ping, scaleSkin:false});

        }
        addEventListener(Event.ENTER_FRAME,onEnterFrm);
        stage.addEventListener(MouseEvent.CLICK, _clicked);
        sim.start();



    }

    /**
     * ..
     * @param e MouseEvent.CLICK
     */
     private function _clicked(e:MouseEvent)
     {  
        if (! isFiring){
            gameBall = sim.addCircle({x:(mouseX/30), y:(2), radius:0.15, density:1, restitution:0.7, friction:0, skin:ball, scaleSkin:false, angularDamping:20});
            isFiring=true;
            ballIcon.gotoAndStop(2);

        }  
     }

    private function liveIcon():void {
        ballIcon=new ballIcon_mc();
        addChild(ballIcon);
        ballIcon.y=30;
    }        

     private function onEnterFrm(e:Event):void
     {          
        ballIcon.x=mouseX;
        if (gameBall && gameBall.body.IsSleeping())
            {
                gameBall.destroy();
                gameBall = null;
                isFiring=false;
                ballIcon.gotoAndStop(1);
            }  
    }

    private function contactListener(e:Event)
    {
        if (simContacts.isCurrentContact(winBox,gameBall))
        {
            // Won.
            trace ('You won!');
            isFiring=false;
            ballIcon.gotoAndStop(1);

            winMsg=new win_mc();
            addChild(winMsg);
            winMsg.y=250;
            winMsg.x=40;
            winMsg.gotoAndPlay(2);

        }

        if (simContacts.isCurrentContact(looseBox,gameBall))
        {
            // Loose.
            trace ('You loose!');
            //gameBall({friction:1,restitution:0});
            isFiring=false;
            ballIcon.gotoAndStop(1);
        }
    }


}

}

Answer 1

制作“你赢了！”每个球消息一次，当玩家获胜时移除事件监听器，并在每次用户创建一个球时添加它。可以多次向同一个对象添加一个事件监听器;事件监听器函数仍然只会被调用一次。

private function clicked(e:MouseEvent)
{  
    if (!isFiring)
    {
        // Add the ball.
        simContacts.addEventListener(QuickContacts.ADD, contactListener);
    }
}

...

private function contactListener(e:Event):void
{
    if (simContacts.isCurrentContact(winBox, gameBall))
    {
        // You win.
        simContacts.removeEventListener(QuickContacts.ADD, contactListener);
    }
    else if (simContacts.isCurrentContact(winBox, gameBall))
    {
        // You lose.
    }
}

Answer 2

或者您可以查看是否添加了winMsg。（对于你要添加它的任何东西。在这个例子中是舞台）。

if (stage.contains(winMsg)) 
{
winMsg=new win_mc();
addChild(winMsg);
winMsg.y=250;
winMsg.x=40;
winMsg.gotoAndPlay(2);
}

所以winMsg只会添加一次。

然后删除winMsg并在完成后将其设置为null。

removeChild(winMsg);
winMsg = null;

PS。设置事件监听器时，最好始终使用弱引用（IMO），否则可能会遇到从内存中清除对象的问题。要做到这一点，只需添加

，false，0，true

到addEventListeners的末尾。 e.g。

simContacts.addEventListener（QuickContacts.ADD，contactListener，false，0，true）;

AS3：防止事件发生两次？

2 个答案: