如何修复错误 1119 as3

Question

我是 as3 的新手。我正在努力解决错误 1119。我不明白如何解决它。 错误是：

通过静态类型 flash.text:TextField 的引用访问可能未定义的属性文本。

package {

import flash.display.MovieClip;
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
import flash.events.Event;
import flash.utils.Timer;
import flash.events.TimerEvent;
import flash.text.TextField;

// public function kan je ook gebruiken in een ander as. file
// private function kan je alleen gebruiken in hetzelfde as. file 
public class firstGame extends MovieClip
{

    public var mcPlayer:MovieClip;

    private var leftKeyIsDown:Boolean;
    private var rightKeyIsDown: Boolean;

    private var aMissileArray: Array;
    private var aEnemyArray: Array; 

    public var scoreTxt: TextField;
    public var ammoTxt : TextField;

    public var menuEnd: mcEndGameScreen;

    private var tEnemyTimer : Timer;

    private var nScore : Number;
    private var nAmmo : Number;

    public function firstGame ()
    {
        playGameAgain(null);
    }

    private function playGameAgain (e:Event) : void
    {
        //initilaiz variables
        aMissileArray = new Array ();
        aEnemyArray = new Array ();

        nScore = 0;
        nAmmo = 20;

        mcPlayer.visible = true;

        updateScoreText();
        updateAmmoText();

        menuEnd.addEventListener("PLAY_AGAIN", playGameAgain);
        menuEnd.hideScreen ();

        //trace("First Game Loaded");
        //Listern for key presses and relesead

        stage.addEventListener(KeyboardEvent.KEY_UP, keyUp);
        stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDown);
        //Setup game event loop
        stage.addEventListener(Event.ENTER_FRAME, gameLoop);

        // create a timer object
        tEnemyTimer = new Timer (1000);
        // listener for timer intervals
        tEnemyTimer.addEventListener(TimerEvent.TIMER, addEnemy); 
        // start out timer
        tEnemyTimer.start();
    }

    private function updateScoreText (): void
    {
        scoreTxt.txt = "Score: " + nScore;
    }

    private function updateAmmoText (): void
    {
        ammoTxt.txt =  "Ammo: " + nAmmo; 
    }
    private function addEnemy (e:TimerEvent) : void
    {
        //trace ("timer ticks")
        // create a new enemy object
        var newEnemy:mcEnemy = new mcEnemy ();
        // add object to the stage
        stage.addChild (newEnemy);
        // add enemy to new enemy to a new enemy array
        aEnemyArray.push(newEnemy);
        trace (aEnemyArray.length);

    }

    private function gameLoop (e:Event) : void
    {
        playerControl();
        clampPlayerToStage();
        checkMissileOffscreen();
        checkEnemiesOffscreen();
        checkMissilesHitsEnemy();
        checkEndGameCondition();
    }

    private function chechEndGameCondition (): void
    {
        //check if player has 0 missiles left and 0 on screen
        if ( nAmmo == 0 && aMissileArray.length == 0)
        {
            // stop player movement
            stage.removeEventListener(KeyboardEvent.KEY_UP, KeyUp);
            stage.removeEventListener(KeyboardEvent.KEY_DOWN, KeyDown);
            // hide the player
            mcPlayer.visible = false;
            // stop spawing enemies
            tEnemyTimer.stop();
            // clear enemies on screen
            for each ( var enemy: mcEnemy in aEnemyArray)
            {
                // destroy the enemy
                enemy.destroyEnemy();
                // remove from enemy array
                aEnemyArray.splice( 0,1);
            }
            // stop the game loop
            if(aEnemyArray.length == 0 )
            {
            stage.removeEventListener(Event.ENTER_FRAME, gameLoop);
            }
            // show our endgame screen
            menuEnd.showScreen(); 
        }

    }

    private function checkMissilesHitsEnemy (): void
    {
        // loop trough current missiles
        for (var i : int = 0 ; i < aMissileArray.length; i++)
        {
            // get our current missile in the  i loop
            var currentMissile : mcMissile = aMissileArray [i];

            // loop trough all our enemies
            // gebruik geen i want die is al gebruikt dus j
            for (var j: int = 0 ; j < aEnemyArray.length; j++)
            {
                // get the current enemy in the j loop
                var currentEnemy: mcEnemy = aEnemyArray [j];

                // test if our current enemy is hitting our current missile
                if(currentMissile.hitTestObject(currentEnemy))
                {
                    // create an explosion
                    // create a new explosion instance/movielcip
                    var newExplosion: mcExplosion = new mcExplosion ();
                    // add our explosion to the stage
                    stage.addChild( newExplosion)
                    // position our expolosion to our enemy
                    newExplosion.x = currentEnemy.x; 
                    newExplosion.y = currentEnemy.y;

                    // remove the missile
                    currentMissile.destroyMissile();
                    // remove the missile from missile array
                    aMissileArray.splice(i, 1);
                    // remove the enemy from the stage
                    currentEnemy.destroyEnemy();
                    // remove the enemy from the enemy array
                    aEnemyArray.splice(j, 1);

                    // add one to our score
                    nScore++;
                    updateScoreTxt ();
                }
            }

        }
    }

    private function checkEnemiesOffscreen (): void
    {
        // loop trough all our enemies
        for (var i:int = 0;i < aEnemyArray.length; i++)
        {
            // get our current ememy in the loop
            var currentEnemy: mcEnemy = aEnemyArray [i];
            // when enemy moves left and is has gone past the and of the left from the stage
            if (currentEnemy.sDirection == "L" && currentEnemy.x  - (currentEnemy.width/2))
            {
                // Remove enemy from our array
                aEnemyArray.slice(i,1); 
                // Remove enemy from stage
                currentEnemy.destroyEnemy();
            } else
            if (currentEnemy.sDirection == "R" && currentEnemy.x > stage.stageWidth + (currentEnemy.width/2))
            {
                // Remove enemy from our array
                aEnemyArray.slice(i,1); 
                // Remove enemy from stage
                currentEnemy.destroyEnemy();
            }

        }
    }

    private function checkMissileOffscreen():void
    {
        //Loop throw all our missiles in our missle array
            // i = counter object
        for (var i: int = 0; i < aMissileArray.length; i++)
        {
            //Get the current missile in the loop
            var currentMissile : mcMissile = aMissileArray [i];
            //Test if current missile is out the buttom of the screen
            if (currentMissile.y > 450 )
            {
                    //Remove current missile from the array
                    aMissileArray.splice(i,1);
                    //Destroy our missile
                    currentMissile.destroyMissile();
            }

        }
    }

    private function clampPlayerToStage ():void
    {
        // if our player is to the left of the stage
        if (mcPlayer.x < (mcPlayer.width/2))
        {
            // set our player to left of the stage
            mcPlayer.x = mcPlayer.width/2;
        }
        // if our player is to the right of the stage
        else if (mcPlayer.x > (stage.stageWidth - (mcPlayer.width/2)))
        {
            //set our player to right of the stage
            mcPlayer.x = stage.stageWidth - (mcPlayer.width/2);
        }
    }

    private function playerControl ():void
    {
            // if our left key is down currently
        if (leftKeyIsDown == true)
        {
                //move to left
            mcPlayer.x -= 5;
        }

            // if our right key is currently down
        if (rightKeyIsDown)
        {
                //move to right
            mcPlayer.x += 5;
        }   
    }

    private function keyUp (e:KeyboardEvent): void
    {
        //trace(e.keyCode)
        //if your left is released
        if (e.keyCode == 37)
        {
            //left key is released
            leftKeyIsDown = false;
        }
        //if your right is released 
        if (e.keyCode == 39)
        {
            //right key is released
            rightKeyIsDown = false;
        }
        //if our spacebarr is released
        if (e.keyCode == 32)
        {
            // test if player has missiles left
            if (nAmmo > 0) 
            {
            nAmmo--;
            updateAmmoTxt();
            //fire a missile
            fireMissile ();
            }
        }

    }

    private function fireMissile ():void 
    {
        // create a new missisile object
        var newMissile : mcMissile = new mcMissile ();
        // add to stage
        stage.addChild(newMissile);
        // position missile
        newMissile.x = mcPlayer.x;
        newMissile.y = mcPlayer.y;
        //add our new missile to our missile array
        aMissileArray.push (newMissile);
        trace(aMissileArray.length)
    }

    private function keyDown (e:KeyboardEvent): void
    {

        //trace(e.keyCode)
        //if your left is pressed
        if (e.keyCode == 37)
        {
            //left key is pressed
            leftKeyIsDown = true;
        }
        //if your right is pressed
        if (e.keyCode == 39)
        {
            //right key is pressed
            rightKeyIsDown = true;
        }
    }


    }

}

如果有人可以帮助我处理 scoreTxt，我想我可以自己完成 ammoTxt。

Answer 1

这是一个错字scoreTxt.txt 应该是scoreTxt.text。

---

错误 1119 说 Access of possibly undefined property <propertyname> through a reference with static type <typename>.

这意味着您的某些代码使用了可能未初始化的对象。在您的情况下，它是 scoreTxt，正如您所知道的那样。

要查看它崩溃的原因，您需要手动检查您的程序。我更喜欢取消注释整个代码块并慢慢缩小问题范围，但这里不需要。

首先，您点击firstGame()，您的文档类的构造函数。

这反过来会命中playGameAgain()，并带有null 参数。

该函数通过一些代码运行......然后它命中updateScoreText()。它在那里崩溃。这给出了以下调用堆栈和执行的代码：

调用栈：

updateScoreText()
from playGameAgain(null) on line "updateScoreText();"
from firstGame() on line "playGameAgain(null);"

执行代码：

playGameAgain(null);

//leads to...
//initilaiz variables
aMissileArray = new Array ();
aEnemyArray = new Array ();

nScore = 0;
nAmmo = 20;

mcPlayer.visible = true;

updateScoreText();
//leads to...
scoreTxt.txt = "Score: " + nScore;//crash

您需要先链接或创建scoreTxt。现在可能是null 或undefined，这就是导致1119 错误的原因。要链接 scoreTxt 以便您的文档类可以找到它，您应该给它们实例名称。如果我是你，我会验证我的实例名称。

您还必须为 ammoTxt 执行此操作。