我有一个带有 HTML5 画布的网页，我用它来显示许多图像以及画布上的四个“描述框”。
目的是用户将能够将图像拖放到他们匹配的描述框中，但是，我在拖放工作时遇到了一些麻烦。
我尝试了几种不同的方法来启用图像拖放，但它们似乎都不起作用。
我遇到的问题是要在画布上显示的内容需要是动态的，即管理员将能够通过更改要在画布中使用的图像的文件名来更改在画布上显示的图像等XML 文件，对于他更愿意使用的任何图像。
所以基本上，我想向在画布上显示图像的 JavaScript 添加代码，以使它们能够在画布上拖放。
有没有人对最好的方法有什么建议？
我的 HTML 页面如下所示：
<!DOCTYPE html>
<html>
<head>
<script src = "kinetic.js" type = "text/javascript"></script>
<title>Home</title>
<script src = "drawLevelOneElements.js" type = "text/javascript"></script>
<script src = "layers&analytics.js" type = "text/javascript"></script>
<script src = "startGameDrawGameElementsDrawStartButton.js" type = "text/javascript"></script>
<script src = "interaction.js" type = "text/javascript"></script>
<script src = "dragAndDrop.js" type = "text/javascript"></script>
<script src = "dragAndDrop1.js" type = "text/javascript"></script>
<script src = "dragAndDrop2.js" type = "text/javascript"></script>
<script src="http://www.html5canvastutorials.com/libraries/kinetic-v4.0.5.js"></script>
</head>
<body onLoad="startGame()">
<section hidden>
<img id="StartButton" src="StartButton.png" alt="Start Button" width="179" height="180" href="javascript:drawLevelOneElements();"/>
</section>
<h1>Home</h1>
<p>The purpose of this website is to teach users the basic principles of running a business by playing the game below. <br /><br /></p>
<canvas id="gameCanvas" width="1000" height="500" style="border:1px solid">
Your browser does not support the canvas element.
</canvas>
<br /><br />
<p>Use this paragraph to enter text that provides the user with instructions for how to play the game. <br />
Update the instructions so that they're appropriate to whatever level the user is currently playing.</p>
<script src = "variables&preloadingImages.js" type = "text/javascript"></script>
</body>
我已经尝试以三种不同的方式添加拖放功能 - 因此我包含了三个拖放 JS 文件，但这些似乎都不起作用。
我用来将图像绘制到画布上的 JavaScript 只是一些数组，每个元素都包含一个图像。我在画布上绘制的每个图像类别都有一个数组，每个类别中的图像数量是可变的。
然后，我使用 JS 的 concat 方法连接数组，将所有图像放在一个名为allImagesArray.
我有以下函数，它将 allImagesArray 中的每个图像绘制在画布上的随机位置：
function drawLevelOneElements(){
/*First, clear the canvas */
context.clearRect(0, 0, myGameCanvas.width, myGameCanvas.height);
/*This line clears all of the elements that were previously drawn on the canvas. */
/*Then redraw the game elements */
drawGameElements();
/*Create the four description areas, and place them near the bottom of the canvas */
/*Create boxes with rounded corners for the description areas */
CanvasRenderingContext2D.prototype.drawDescriptionArea = function(x, y, width, height, radius, stroke){
if(typeof stroke == "undefined" ){
stroke = true;
}
if(typeof radius === "undefined"){
radius = 5;
}
this.beginPath();
this.moveTo(x + radius, y);
this.lineTo(x + width - radius, y);
this.quadraticCurveTo(x + width, y, x + width, y + radius);
this.lineTo(x + width, y + height - radius);
this.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
this.lineTo(x + radius, y + height);
this.quadraticCurveTo(x, y + height, x, y + height - radius);
this.lineTo(x, y + radius);
this.quadraticCurveTo(x, y, x + radius, y);
this.closePath();
if(stroke){
context.stroke();
}
}
context.drawDescriptionArea(70, 400, 120, 70);
context.font = '25pt Calibri';
context.strokeText('Asset', 90, 440);
context.drawDescriptionArea(300, 400, 120, 70);
context.strokeText('Liability', 310, 440);
context.drawDescriptionArea(540, 400, 120, 70);
context.strokeText('Income', 550, 440);
context.drawDescriptionArea(750, 400, 180, 70);
context.strokeText('Expenditure', 760, 440);
/*Now draw the images to the canvas */
/*First, create variables for the x & y coordinates of the image that will be drawn.
the x & y coordinates should hold random numbers, so that the images will be
drawn in random locations on the canvas.*/
var imageX = Math.floor(Math.random()*100);
var imageY = Math.floor(Math.random()*100);
/*Create a 'table' of positions that the images will be drawn to */
var imagePositionsX = [20, 80, 140, 200, 260, 320, 380, 440, 500, 560];
var imagePositionsY = [20, 60, 100, 140, 180, 220, 260, 300, 340, 380];
/*Draw all images from assetsImageArray */
/*Use a while loop to loop through the array, get each item and draw it. */
var arrayIteration = 0;
console.log('All Images Array length: ' + allImagesArray.length); /*Display the length of the array in the console, to check it's holding the correct number of images. */
while(arrayIteration < allImagesArray.length){
var randomPositionX = Math.floor(Math.random()*10);
var randomPositionY = Math.floor(Math.random()*10);
context.drawImage(allImagesArray[arrayIteration], imageX, imageY, 50, 50);
console.log(arrayIteration); /*Display the current array position that's being drawn */
arrayIteration = arrayIteration+1;
/*Now try changing the values of imageX & imageY so that the next image is drawn to a
different location*/
imageX = imagePositionsX[randomPositionX]; /* imageX+(Math.floor(Math.random()*100)); */
imageY = imagePositionsY[randomPositionY]; /* imageY+(Math.floor(Math.random()*100)); */
}
}
该函数还在画布上绘制了四个“描述区域”，分别标记为“资产”、“负债”、“收入”和“支出”。
用户需要做的是将每个图像拖到其相应的“描述区域”。当图像被拖到正确的描述区域时，它应该从画布上消失。
但是，尽管我将图像和描述区域绘制到画布上，但我似乎无法弄清楚如何向图像添加拖放功能。
我在网上查看了几个示例，但似乎无法让它们中的任何一个工作 - 我想知道是否是因为我正在使用 while 循环从数组中绘制图像？我还查看了该网站上提出的其他问题，但似乎无法在其中任何一个中找到答案。
我查看了http://www.html5canvastutorials.com/kineticjs/html5-canvas-drag-and-drop-an-image-tutorial/和http://www.html5canvastutorials.com/labs/html5上的教程-canvas-drag-and-drop-multiple-images-with-kineticjs/但似乎无法使这些示例与我的代码一起使用。有没有人知道如何使用我的函数向画布上绘制的每个图像添加拖放drawLevelOneElements()功能？