ActionScript 3: «Ошибка типа: ошибка # 1009: невозможно получить доступ к свойству или методу ссылки на пустой объект». на переключателе

Question

Я пишу простое меню с ActionScript3 и вложенными случаями переключения.Для этого необходимо проверить текущий кадр с выбранным меню, и если выбранное меню ссылается на другое меню, выполнить переход, а затем перейти к выбранному кадру, и, если выбранное меню является текущим кадром, отслеживается простое сообщение.Но когда выбранное меню и текущий кадр совпадают, я получаю это раздражающее сообщение, и я не знаю, что мне нужно сделать, чтобы решить проблему.

Мой код:

//Import TweenMax
import com.greensock.*;;
import com.greensock.plugins.*;
import flash.events.MouseEvent;

var frameNumber:int = currentFrame;

TweenPlugin.activate([BlurFilterPlugin]);

//Add the buttons into an array
var buttonsArray:Array = new Array(s1t1,s1t2,s1t3,s1t4,s1t5);

//Loop through the buttons array
for (var i:uint = 0; i < buttonsArray.length; i++) {
    //Add event listeners for the button
    buttonsArray[i].addEventListener(MouseEvent.MOUSE_OVER, mouseOverButton);
    buttonsArray[i].addEventListener(MouseEvent.CLICK, buttonClicked);
}

//Move the buttonBackground under the home button (= starting position)
buttonBackground.x = s1t1.x;
buttonBackground.y = s1t1.y;

//Make the buttonBackground a bit bigger than the home button
buttonBackground.width = s1t1.width + 10;
buttonBackground.height = s1t1.height + 10;

//Tween the buttonBackground to a random color using TweenMax
TweenMax.to(buttonBackground, 0.1, {tint: Math.random() * 0xffffff});

//This function is called when the mouse is over a button
function mouseOverButton(e:MouseEvent):void {
    //trace(e.target.name + " was touched!");
    //Assign the button to a local variable
    var button:MovieClip = (MovieClip)(e.target);

    //Calculate the new target width and height for the buttonBackground
    var targetWidth:Number = button.width + 10;
    var targetHeight:Number = button.height + 10;

    //Tween the buttonBackground's position, size and color (color is random)
    TweenMax.to(buttonBackground, 0.5, {x: button.x, y: button.y,
    width:targetWidth, height:targetHeight, tint: Math.random() * 0xffffff});
}

//This function is called when a button is clicked
function buttonClicked(e:MouseEvent):void {
    switch(e.target.name){
        case "s1t1":
            switch (currentFrame){
                case 5:
                    trace("Nowhere to go!");
                break;
                case 6:
                    var myTM:TransitionManager = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    var myTM:TransitionManager = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    var myTM:TransitionManager = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    var myTM:TransitionManager = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 5;
            myTM.addEventListener("allTransitionsOutDone", doneTrans)
        break;
        case "s1t2":
            switch (currentFrame){
                case 5:
                    var myTM:TransitionManager = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    trace("Nowhere to go!");
                break;
                case 7:
                    var myTM:TransitionManager = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    var myTM:TransitionManager = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    var myTM:TransitionManager = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 6;
            myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t3":
            switch (currentFrame){
                case 5:
                    var myTM:TransitionManager = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    var myTM:TransitionManager = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    trace("Nowhere to go!");
                break;
                case 8:
                    var myTM:TransitionManager = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    var myTM:TransitionManager = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 7;
            myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t4":
            switch (currentFrame){
                case 5:
                    var myTM:TransitionManager = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    var myTM:TransitionManager = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    trace("Nowhere to go!");
                break;
                case 7:
                    var myTM:TransitionManager = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    var myTM:TransitionManager = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 8;
            myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t5":
            switch (currentFrame){
                case 5:
                    var myTM:TransitionManager = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    var myTM:TransitionManager = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    var myTM:TransitionManager = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    var myTM:TransitionManager = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    trace("Nowhere to go!");
                break;
            }
            frameNumber = 9;
            myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
    }
}
function doneTrans(e:Event):void{
    trace("Going frame: "+frameNumber);
    gotoAndStop(frameNumber);
}

Я использую Flash CS5 и плагин "greensock", и моя ошибка:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
        at _009_fla::MainTimeline/buttonClicked()

Answer 1

проблема в том, что вы добавляете прослушиватель событий в myTM, когда его там нет (при нажатии кнопки меню на текущей странице), поэтому я быстро исправил это, проверив, создан ли экземпляр myTM (не ноль), и если да, добавьтеслушатель событий, надеюсь, это решит вашу проблему.

замените функцию buttonClicked на эту:

function buttonClicked(e:MouseEvent):void {
    //declaring new variables inside conditional cases is a bad practice
    var myTM:TransitionManager;
    switch(e.target.name){
        case "s1t1":
            switch (currentFrame){
                case 5:
                    trace("Nowhere to go!");
                break;
                case 6:
                    myTM = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    myTM = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    myTM = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    myTM = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 5;
            //myTM.addEventListener("allTransitionsOutDone", doneTrans)
        break;
        case "s1t2":
            switch (currentFrame){
                case 5:
                    myTM = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    trace("Nowhere to go!");
                break;
                case 7:
                    myTM = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    myTM = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    myTM = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 6;
            //myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t3":
            switch (currentFrame){
                case 5:
                    myTM = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    myTM = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    trace("Nowhere to go!");
                break;
                case 8:
                    myTM = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    myTM = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 7;
            //myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t4":
            switch (currentFrame){
                case 5:
                    myTM = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    myTM = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    trace("Nowhere to go!");
                break;
                case 7:
                    myTM = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    myTM = new TransitionManager(s1text5);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                default:
                    trace("Nowhere to go!");
            }
            frameNumber = 8;
            //myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
        case "s1t5":
            switch (currentFrame){
                case 5:
                    myTM = new TransitionManager(s1text1);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 6:
                    myTM = new TransitionManager(s1text2);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 7:
                    myTM = new TransitionManager(s1text3);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 8:
                    myTM = new TransitionManager(s1text4);
                    myTM.startTransition({type:Fade, direction:Transition.OUT, duration:0.25, easing:Back.easeOut});
                break;
                case 9:
                    trace("Nowhere to go!");
                break;
            }
            frameNumber = 9;
            //myTM.addEventListener("allTransitionsOutDone", doneTrans);
        break;
    }

    //if myTM is not null (not empty) add the event listener
    if (myTM)
    {
        myTM.addEventListener("allTransitionsOutDone", doneTrans);
    }
}

в вашем коде есть много возможностей для улучшения, например, его можно переделать виспользуйте только один переключатель или несколько лучших подходов, но я не хочу сильно менять ваш код.