如何在多文件上传器中启用提交按钮直到条件？

Question

我正在做一个网络应用程序，人们会上传 2 张图像，我需要通过 python 代码。因此，我只想让他们在上传2张图片时发送。

我一直在阅读其他帖子，例如：

How to disable submit button until file is selected

Enable submit button after uploading more than 1 file

但我无法将其推断到我的案例中：

<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" type="text/css" href="https://unpkg.com/file-upload-with-preview@3.4.3/dist/file-upload-with-preview.min.css">
</head>


<body>
  <!-- Uploader -->
<div class="custom-file-container" data-upload-id="myImage">
    <label>Upload your images <a href="javascript:void(0)" class="custom-file-container__image-clear" title="Clear Image">&times;</a></label>

    <label class="custom-file-container__custom-file" >
      <form id="upload-form" action="{{url_for('upload')}}" method="POST" enctype="multipart/form-data">
      <input type="file" class="custom-file-container__custom-file__custom-file-input" accept="image/*" aria-label="Choose File" multiple>
      <input type="hidden" name="MAX_FILE_SIZE" value="10485760" />
      <span class="custom-file-container__custom-file__custom-file-control"></span>
    </label>
    <div class="custom-file-container__image-preview"></div>
</div>
<input type="submit" name="send" disabled/>
</div>


<script src="https://unpkg.com/file-upload-with-preview@3.4.3/dist/file-upload-with-preview.min.js"></script>

<script>
      var upload = new FileUploadWithPreview('myImage', {showDeleteButtonOnImages: true, text: {chooseFile: 'Nom del fitxer', browse: 'Examina'}})
</script>

<script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>

<script>

$(document).ready(
    function(){
        $('input:file').change(
            function(){
                if ($(this).val()) {
                    $('input:submit').attr('disabled',false);; 
                } 
            }
            );
    });

</script>

</body>
</html>

最后添加的脚本是第一个link中给出的解决方案，可以正常工作，但不是我想要的。

文件上传器代码来自 https://github.com/promosis/file-upload-with-preview，其中我看到有一个名为 selectedFilesCount 的方法可能很有用。

感谢您抽出宝贵时间，如果您在我的代码中看到一些废话，我深表歉意，但我是这些语言的新手...

Answer 1

您可以挂接到上传对象的 upload.cachedFileArray 以检查 array 长度以验证是否已选择 2 个文件进行上传。这是通过 window event listeners fileUploadWithPreview:imageSelected 和 fileUploadWithPreview:imageDelete 绑定的 toggle() 函数检查的，因此如果图像在被选中后被删除，您仍然可以执行规则 2：

$(document).ready(function() {

});

var toggle = function() {
  //console.log(upload.cachedFileArray.length);
  if (upload.cachedFileArray.length == 2) {
    $('input:submit').attr('disabled', false);
  } else {
    $('input:submit').attr('disabled', true);
  }
};

window.addEventListener('fileUploadWithPreview:imageSelected', function(e) {
  // optionally you could pass the length into the toggle function as a param
  // console.log(e.detail.cachedFileArray.length);
  toggle();
});

window.addEventListener('fileUploadWithPreview:imageDeleted', function(e) {
  // optionally you could pass the length into the toggle function as a param
  // console.log(e.detail.cachedFileArray.length);
  toggle();
});

<!DOCTYPE html>
<html>

<head>
  <link rel="stylesheet" type="text/css" href="https://unpkg.com/file-upload-with-preview@3.4.3/dist/file-upload-with-preview.min.css">
</head>

<body>
  <!-- Uploader -->
  <div class="custom-file-container" data-upload-id="myImage">
    <label>Upload your images <a href="javascript:void(0)" class="custom-file-container__image-clear" title="Clear Image">&times;</a></label>

    <label class="custom-file-container__custom-file">
      <form id="upload-form" action="{{url_for('upload')}}" method="POST" enctype="multipart/form-data">
      <input type="file" class="custom-file-container__custom-file__custom-file-input" accept="image/*" aria-label="Choose File" multiple>
      <input type="hidden" name="MAX_FILE_SIZE" value="10485760" />
      <span class="custom-file-container__custom-file__custom-file-control"></span>
    </label>
    <div class="custom-file-container__image-preview"></div>
  </div>
  <input type="submit" name="send" disabled/>
  </div>
  <script src="https://unpkg.com/file-upload-with-preview@3.4.3/dist/file-upload-with-preview.min.js"></script>
  <script>
    var upload = new FileUploadWithPreview('myImage', {
      showDeleteButtonOnImages: true,
      text: {
        chooseFile: 'Nom del fitxer',
        browse: 'Examina'
      }
    });
  </script>
  <script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>
</body>

</html>

如何在多文件上传器中启用提交按钮直到条件？

How to enable submit button until condition in a multiple file uploader?

html

javascript

forms

jquery

submit