javascript push()失败
我试图将卡片添加到Deck对象中的数组中，但由于某种原因，push()失败了。我之前已经让它工作了，但在做了一些改变后，我实际上把它搞砸了。( "testX“写入是为了调试目的)
<!DOCTYPE HTML>
<html>
<head>
<style>
#myCanvas {
border: 1px solid #9C9898;
}
body {
margin: 0px;
padding: 0px;
}
</style>
<script type="text/javascript">
<!--
//draws the game
window.onload = function() {
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext("2d");
//draws the rectangles that will be the card
var cardHeight = 125,
cardWidth = 80;
context.beginPath();
//draws the top row of 5 cards
for(var x=0;x<5;x++){
context.rect(10+(x*(cardWidth+10)),10,cardWidth,cardHeight);
}
//draws the bottom row of 5 cards
for(x=0;x<5;x++){
context.rect(10+(x*(cardWidth+10)),150,cardWidth,cardHeight);
}
//draws the deck
context.rect(10+5*cardWidth+65,(150-10)/2,cardWidth,cardHeight);
context.fillStyle = 'white';
context.fill();
context.lineWidth = 2;
context.strokeStyle = 'black';
context.stroke();
};
function Deck(){
//creates the unshuffled deck (loadedDeck) once to make the shuffling process faster
var loadedDeck = new Array(),
realDeck;
this.loadTheDeck = function(){ //method
for(x=1;x<=13;x++){
this.loadedDeck.push(x+" Spades"); //<---issue line (all 4 are failing though this is the first)
this.loadedDeck.push(x+" Clubs");
this.loadedDeck.push(x+" Hearts");
this.loadedDeck.push(x+" Diamonds");
}
document.write(this.loadedDeck);
};
this.loadTheDeck(); //creates the unshuffled deck when the Deck is instantiated
//resets the deck and randomizes
this.shuffle = function(){ //method
//creates the real deck
this.realDeck = this.loadedDeck;
//write shuffle function
};
this.shuffle(); //shuffles the Deck when instantiated
}
document.write("test-1");
var myDeck = new Deck();
document.write("test0");
document.write(this.realDeck);
document.write("test1");
-->
</script>
</head>
<body>
<canvas id="myCanvas" height="300" width="600"></canvas>
</body>
</html>以下是代码的演示：http://jsfiddle.net/NfmsR/2/
回答 3
Stack Overflow用户
发布于 2012-06-05 01:11:04
当您运行此行时：
this.loadedDeck.push(x+" Spades");您正在使用this.loadedDeck数组。您是否已将其定义为Deck对象的一部分？不是：
var loadedDeck = new Array(),
realDeck;将声明更改为以下内容，它应该会起作用：
this.loadedDeck = []; // I'd use [] instead of new Array().
this.realDeck = [];正如@j08691指出的那样，您还需要将realDeck更改为this.realDeck，因为您在这里的调用方式与此类似：
this.shuffle = function(){ //method
//creates the real deck
this.realDeck = this.loadedDeck;
//write shuffle function
};Stack Overflow用户
发布于 2012-06-05 01:08:44
你引用"loadedDeck“就好像它是你的"Deck”对象的属性。它不是；它只是构造器闭包的一个局部变量。
就叫它"loadedDeck“吧，看看有没有帮助。"realDeck“也是如此。
this.loadTheDeck = function(){ //method
for(var x=1;x<=13;x++){
loadedDeck.push(x+" Spades"); //<---issue line (all 4 are failing though this is the first)
loadedDeck.push(x+" Clubs");
loadedDeck.push(x+" Hearts");
loadedDeck.push(x+" Diamonds");
}另外，改掉滥用document.write进行调试的习惯也是个好主意。也不要忘了用var声明像"x“这样的东西！
Stack Overflow用户
发布于 2012-06-05 01:11:24
您的Deck对象是通过this访问的，它没有"loadedDeck"-property。loadedDeck是一个局部变量。只需删除"this.“即可。
https://stackoverflow.com/questions/10885192
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