html5的文件api与jquery的例子？

Question

我想使用html5的文件api,结合外部拖放功能(将外部文件拖到指定的位置并捕获其内容)和jquery.我找到了一个有效的非jquery示例:(html5 demo:file api)

 var drop = document.getElementById('drop');  
 drop.ondragover = function () {this.className = 'focus'; return false;};  
 drop.ondragend = function () { this.className = ''; return false; };  
 drop.ondrop=function(e) {  
          this.className = '';  
          e.preventDefault();  
          var file = e.dataTransfer.files[0];  
          var reader = new FileReader();  
          reader.onload = function (evt) {  
                console.log(evt.target.result);  
          }  
          reader.readAsText(file);  
      }; 

这很好用.现在我想让这更像是一个jquery-ish,我试过:

 $("#drop").bind('ondragover',function() {this.addClass('focus'); return false;})
.bind("ondragend",function () { this.removeClass('focus'); return false;})  
.bind("ondrop",function(e) {  
         this.removeClass("focus");  
         e.preventDefault();  
         var file = e.dataTransfer.files[0];  
         var reader = new FileReader();  
         reader.onload = function (evt) {  
               console.log(evt.target.result);  
         }  
         reader.readAsText(file);  
     });   

但这不起作用,没有一个绑定事件似乎被触发.我也试图松开事件名的"on"部分,但这也行不通.希望这里有人能发光吗？

问候,jeroen.

Answer 1

Gidon的描述解决了这个问题.这是一个完全编码的示例,以防其他人正在寻求解决此问题并想要更多细节.

// Bindings to HTML; replace these with your components.
var $dropArea = $('#dropArea');
var $picsHolder = $('#picsHolder');

// Attach our drag and drop handlers.
$dropArea.bind({
  dragover: function() {
    $(this).addClass('hover');
    return false;
  },
  dragend: function() {
    $(this).removeClass('hover');
    return false;
  },
  drop: function(e) {
    e = e || window.event;
    e.preventDefault();

    // jQuery wraps the originalEvent, so we try to detect that here...
    e = e.originalEvent || e;
    // Using e.files with fallback because e.dataTransfer is immutable and can't be overridden in Polyfills (http://sandbox.knarly.com/js/dropfiles/).            
    var files = (e.files || e.dataTransfer.files);

    var $img = $('<img src="" class="uploadPic" title="" alt="" />');
    for (var i = 0; i < files.length; i++) {
      (function(i) {
        // Loop through our files with a closure so each of our FileReader's are isolated.
        var reader = new FileReader();
        reader.onload = function(event) {
          var newImg = $img.clone().attr({
            src: event.target.result,
            title: (files[i].name),
            alt: (files[i].name)
          });

          // Resize large images...
          if (newImg.size() > 480) {
            newImg.width(480);
          }

          $picsHolder.append(newImg);
        };
        reader.readAsDataURL(files[i]);
      })(i);
    }

    return false;
  }
});

#dropArea {
  border: 10px dashed;
  border-radius: 10px;
  border-color: gray;
  width: 200px;
  height: 200px;
}
#dropArea:hover {
  border-color: black;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="picsHolder"></div>
<div id="dropArea"></div>

Answer 2

解决方案很简单.

1. 丢失on前缀(这就是为什么没有抛出事件)
2. this.=> $(this). (这就是为什么当事件被抛出时没有发生任何事情,它给出了一个错误).

和我一起工作.