AS3 - MouseEvent.CLICK会在添加侦听器之前触发鼠标单击

时间：2013-06-05 14:41:58

标签： actionscript-3

我是AS3的新手，并制作了一款简单的"asteroids"游戏，屏幕上有游戏，resetButton可让用户再次玩游戏。当用户点击重置按钮时，屏幕上的游戏和重置按钮将从舞台上移除，并且游戏本身将与eventListeners一起添加到舞台上。其中一个是添加到MouseEvent.CLICK的{​​{1}}侦听器，它调用stage函数。此功能绘制一个项目符号并将其添加到舞台上（代码的其他部分然后使子弹在屏幕上移动）。

我遇到的问题是，当用户点击重置按钮时，游戏切换屏幕会被正确删除，并且正确的游戏（玩家，小行星，eventListeners）会被正确地添加到舞台上，但同时也是如此即使用户在点击fireBullet后未点击，也会触发bullet次。

我的reset button功能是这样的：

gameOver()

然后，stage.removeChild() all objects stage.removeEventListener() all listeners null out all objects draw and add to the stage the game over text and resetButton addEventListener(MouseEvent.CLICK, onReset) to the resetButton 函数如下所示：

onReset()

stage.removeChild() the gameover text and the resetButton call gameStart(); 函数如下所示：

gameStart()

我在每个函数中添加了跟踪以查看发生了什么，这就是流程：

initialize variables
draw and add player and asteroids on the screen
add eventListeners including MouseEvent.Click, fireBullet

我已经读过某个地方一直调度事件，无论是否有任何侦听器正在侦听它们，所以我怀疑我的MouseEvent.CLICK侦听器是从重置按钮的时间开始点击鼠标按钮单击，即使之后将此侦听器添加到舞台中。

我没有足够的AS3或编程经验来确定是否真的如此，我该怎么做才能确保added fireBullet listener //this is gameStart() function being called from Main() and adding everything to the stage the first time fired bullet //shooting at the asteroids fired bullet fired bullet fireBullet listener should have been removed //this is gameOver() being called that removes everything from the stage and adds the resetButton clicked on reset added fireBullet listener //gameStart() being called again from onReset() function fired bullet //I did not click a second time after clicking on reset 监听器不响应之前发生的任何点击加入舞台，所以对此的任何帮助将不胜感激。

====

修改

我假设我遇到了逻辑问题或者对AS3和flash一无所知，所以我只是使用上面的伪代码。下面是完整的.as文件的链接，包括生成的.swf 以下是完整的相关功能 https://www.dropbox.com/sh/a4rlasq8o0taw82/wP3rB6KPKS

MouseEvent.CLICK这是从Main

调用的 
private function startGame():void

{ //initialize variables bulletArray = []; cleanupBullets = []; bulletSpeed = 10; score = 0; asteroid1Speed = 0; asteroid2Speed = 0; asteroid3Speed = 0; asteroid4Speed = 0; //draw player and asteroids ship = drawPlayer(); asteroid1 = drawAsteroid(); asteroid2 = drawAsteroid(); asteroid3 = drawAsteroid(); asteroid4 = drawAsteroid(); //embarrasing and inefficient code to get random number between -5 and 5 without a 0 asteroid1Speed = Math.ceil(Math.random() * 10 -5); if (asteroid1Speed == 0) asteroid1Speed = returnNonZero(asteroid1Speed); asteroid2Speed = Math.ceil(Math.random() * 10 -5); if (asteroid2Speed == 0) asteroid2Speed = returnNonZero(asteroid2Speed); asteroid3Speed = Math.ceil(Math.random() * 10 -5); if (asteroid3Speed == 0) asteroid3Speed = returnNonZero(asteroid3Speed); asteroid4Speed = Math.ceil(Math.random() * 10 -5); if (asteroid4Speed == 0) asteroid4Speed = returnNonZero(asteroid4Speed); //trace(asteroid1Speed, asteroid2Speed, asteroid3Speed, asteroid4Speed); //add asteroids to stage stage.addChild(asteroid1); stage.addChild(asteroid2); stage.addChild(asteroid3); stage.addChild(asteroid4); //position player and add to stage ship.x = 40; ship.y = 40; stage.addChild(ship); //add event listeners stage.addEventListener(Event.ENTER_FRAME, onFrame); stage.addEventListener(MouseEvent.CLICK, fireBullet); trace("added fireBullet listener"); } 这是从我不包括的private function gameOver():void（称为每帧）函数中调用的（它太大而且不完全相关）。当所有小行星被移除时都会调用它。

onFrame

{ //remove any remaining bullets off the screen for each (var item:Sprite in bulletArray) { stage.removeChild(item); } //null out objects and remove listeners bulletArray = null; stage.removeEventListener(Event.ENTER_FRAME, onFrame); stage.removeEventListener(MouseEvent.CLICK, fireBullet); //check if the listener has actually been removed if (!(stage.hasEventListener(MouseEvent.CLICK))) { trace("fireBullet listener should have been removed"); } stage.removeChild(ship); ship = null //graphic for resetButton resetButton = new Sprite(); resetButton.graphics.beginFill(0xFFFFFF); resetButton.graphics.drawRect(0, 0, 100, 50); resetButton.graphics.endFill(); //position for resetButton resetButton.x = 250; resetButton.y = 300; //text for resetButton resetTextField = new TextField(); var resetTextFormat:TextFormat = new TextFormat(); resetTextFormat.size = 30; resetTextFormat.color = 0x000000; resetTextField.defaultTextFormat = resetTextFormat; resetTextField.selectable = false; resetTextField.text = "RESET"; resetButton.addChild(resetTextField); //add resetButton and listener stage.addChild(resetButton); resetButton.addEventListener(MouseEvent.CLICK, onReset); //gameover text gameOverTxtField = new TextField(); gameOverFormat = new TextFormat(); gameOverFormat.size = 50; gameOverFormat.color = 0xFFFFFF; gameOverFormat.align = "center"; gameOverTxtField.defaultTextFormat = gameOverFormat; gameOverTxtField.selectable = false; gameOverTxtField.text = "GAME OVER"; gameOverTxtField.width = 660; gameOverTxtField.height = 200; gameOverTxtField.x = -10; gameOverTxtField.y = 20; stage.addChild(gameOverTxtField); } 

private function onReset(e:MouseEvent):void

2 个答案:

答案 0 :(得分：3)

正在发生的事情是MouseEvent.CLICK是bubbling event。在Flash中，事件有三个阶段：“捕获阶段”，“目标”阶段和“冒泡阶段”。您可以在此Adobe article中阅读相关内容。

您的重置按钮的点击事件处理程序发生在“目标”阶段。如果您在重置按钮单击处理程序中跟踪事件的阶段，它将显示event.phase为2.每docs，1 =“捕获阶段”，2 =“在目标”，3 = “冒泡阶段”。

在重置按钮单击处理程序完成其工作后，该事件随后通过显示列表进行回火。由于stage位于显示列表的顶部，因此点击事件会“冒泡”到舞台上。到那时，你又开始了游戏并添加了舞台的点击事件处理程序。因此，舞台的点击处理程序也会被触发。

您可以通过在event.phase方法中追踪bulletFired()的值来确认这一点：

private function fireBullet(e:MouseEvent):void 
{ 
    // most of this time it will trace out 2 for the phase
    // except when you click on an asteroid when firing or
    // click the reset button
    trace("fired bullet, event phase: " + e.eventPhase);
    bullet = drawBullet(); 
    bullet.y = ship.y; 
    bullet.x = ship.x + (ship.width / 2); 
    bulletArray.push(bullet); 
    stage.addChild(bullet); 
}

要解决此问题，您可以使用onReset()方法阻止事件冒泡：

private function onReset(e:MouseEvent):void 
{
    // prevent this event from bubbling
    e.stopPropagation();
    trace("clicked on reset"); 
    //remove gameover objects and null them 
    resetButton.removeEventListener(MouseEvent.CLICK, onReset); 
    stage.removeChild(gameOverTxtField); 
    stage.removeChild(resetButton); 
    resetButton = null; 
    gameOverTxtField = null; 
    //restart the game 
    startGame(); 
}

答案 1 :(得分：0)

听起来像你之前的游戏迭代没有移除MOUSE.CLICK事件监听器。即使游戏被移除，MOUSE.CLICK事件也会继续触发您添加到其中的任何处理程序，例如; addEventListener（MOUSE.ClICK，）。删除游戏后，您还需要删除EventListener（MOUSE.CLICK，）。

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