Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
534 views
in Technique[技术] by (71.8m points)

javascript - 冲突的@Dragenter @Dragleave / v-show事件持续迅速触发(Conflicting @Dragenter @Dragleave / v-show Events keep firing rapidly)

虫子

pointer-events: none;

(指针事件:无;)

has already been implemented , in debug , the boolean kept rapidly switching between true and false for both "dragging" & draggingOL"

(已经实现了,在调试中,对于“拖动”和“拖动OL”,布尔值一直在true和false之间快速切换。)

HTML Structure

(HTML结构)

     <ol id="product-images" @dragenter="draggingOL=true" @dragleave="draggingOL=false">

        <li v-for="(file, key) in files" style="pointer-events: none;"></li>

      </ol>


      <div v-show="files.length < 1 || draggingOL == true">
         <div ref="fileform" :class="['next-upload-dropzone', dragging ? 'css1' : '', draggingOL ? 'css1 css2' : '']" @dragenter="dragging=true" @dragleave="dragging=false">

         </div>
      </div>

Basically after you drag an image into the DIV tag, the OL Tag will appear.

(基本上,将图像拖入DIV标签后,将显示OL标签。)

The OL tag doesn't have a draggable so i added Dragenter and leave to OL

(OL标签没有可拖动对象,因此我添加了Dragenter并留给OL)

When i add the second dragenter to OL tag , when you drag a image into the area, the boolean of both dragging & draggingOL will rapidly switch between true and false at 0.5s interval.

(当我将第二个Dragenter添加到OL标签时,将图像拖到该区域时,dragging和draggingOL的布尔值都将以0.5s的间隔在true和false之间快速切换。)

Same for the css, show and unshow very rapidly.

(对于CSS同样如此,显示和取消显示的速度非常快。)

I tried a few ways including only one dragenter ONLY, same issue.

(我尝试了几种方法,仅包括一个Dragenter,同样的问题。)

Perhaps the issue is with v-show, i'm not sure.

(我不确定这可能与v-show有关。)

image的图片" referrerpolicy="no-referrer"> Above is the image of DIV tag

(上面是DIV标签的图像)

OL图片 Above is image of OL tag

(上面是OL标签的图片)

Javascript

(Java脚本)

var dropFileApp = new Vue({
    el: '#dropfile',
    data: {
        dragAndDropCapable: false,
        dragging : false,
        draggingOL : false,
        files: [],
        uploadPercentage: 0
    },
    // define methods under the `methods` object
    mounted(){
  /*
    Determine if drag and drop functionality is capable in the browser
  */
  this.dragAndDropCapable = this.determineDragAndDropCapable();

  /*
    If drag and drop capable, then we continue to bind events to our elements.
  */
  if( this.dragAndDropCapable ){
    /*
      Listen to all of the drag events and bind an event listener to each
      for the fileform.
    */
    ['drag', 'dragstart', 'dragend', 'dragover', 'dragenter', 'dragleave', 'drop'].forEach( function( evt ) {
      /*
        For each event add an event listener that prevents the default action
        (opening the file in the browser) and stop the propagation of the event (so
        no other elements open the file in the browser)
      */
      this.$refs.fileform.addEventListener(evt, function(e){
        e.preventDefault();
        e.stopPropagation();
      }.bind(this), false);
    }.bind(this));

    /*
      Add an event listener for drop to the form
    */

    this.$refs.fileform.addEventListener('drop', function(e){
      /*
        Capture the files from the drop event and add them to our local files
        array.
      */
      for( let i = 0; i < e.dataTransfer.files.length; i++ ){
        this.files.push( e.dataTransfer.files[i] );
        this.getImagePreviews();
      }
      console.log((this.files.length))
      /*
        Instantly upload files
      */
      this.submitFiles();
    }.bind(this));
  }
},

methods: {
  /*
    Determines if the drag and drop functionality is in the
    window
  */
  determineDragAndDropCapable(){
    /*
      Create a test element to see if certain events
      are present that let us do drag and drop.
    */
    var div = document.createElement('div');

    /*
      Check to see if the `draggable` event is in the element
      or the `ondragstart` and `ondrop` events are in the element. If
      they are, then we have what we need for dragging and dropping files.

      We also check to see if the window has `FormData` and `FileReader` objects
      present so we can do our AJAX uploading
    */
    return ( ( 'draggable' in div )
            || ( 'ondragstart' in div && 'ondrop' in div ) )
            && 'FormData' in window
            && 'FileReader' in window;
  },

  /*
    Gets the image preview for the file.
  */
  getImagePreviews(){
    /*
      Iterate over all of the files and generate an image preview for each one.
    */
    for( let i = 0; i < this.files.length; i++ ){
      /*
        Ensure the file is an image file
      */
      if ( /.(jpe?g|png|gif)$/i.test( this.files[i].name ) ) {
        /*
          Create a new FileReader object
        */
        let reader = new FileReader();

        /*
          Add an event listener for when the file has been loaded
          to update the src on the file preview.
        */
        reader.addEventListener("load", function(){
          this.$refs['preview'+parseInt( i )][0].src = reader.result;
        }.bind(this), false);

        /*
          Read the data for the file in through the reader. When it has
          been loaded, we listen to the event propagated and set the image
          src to what was loaded from the reader.
        */
        reader.readAsDataURL( this.files[i] );
      }else{
        /*
          We do the next tick so the reference is bound and we can access it.
        */
        this.$nextTick(function(){
          this.$refs['preview'+parseInt( i )][0].src = '/images/file.png';
        });
      }
    }
  },

  /*
    Submits the files to the server
  */
  submitFiles(){
    /*
      Initialize the form data
    */
    let formData = new FormData();

    /*
      Iteate over any file sent over appending the files
      to the form data.
    */
    for( var i = 0; i < this.files.length; i++ ){
      let file = this.files[i];

      formData.append('files[' + i + ']', file);
    }

    /*
      Make the request to the POST /file-drag-drop URL
    */
    axios.post( '/file-drag-drop',
      formData,
      {
        headers: {
            'Content-Type': 'multipart/form-data'
        },
        onUploadProgress: function( progressEvent ) {
        //Showing Loading   
        }.bind(this)
      }
    ).then(function(){
      console.log('SUCCESS!!');
    })
    .catch(function(){
      console.log('FAILURE!!');
    });
  },

  /*
    Removes a select file the user has uploaded
  */
  removeFile( key ){
    this.files.splice( key, 1 );
  }
}
})

I will continue to test and debug and update this thread.

(我将继续测试,调试和更新此线程。)

  ask by CodeGuru translate from so

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

I had similar problem.

(我有类似的问题。)

It has been resolved, you need to prevent event bubbling for Vue events: Prevent event bubbling in Vue

(已解决,您需要为Vue事件阻止事件冒泡:在Vue中阻止事件冒泡)

<div v-on:dragleave.self="dragLeave($event)">
    ...
</div>

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...