How to upload multiple H5 images in Angular

This article will share with you the function of uploading images using angular. During the development process, I encountered many problems and they were finally solved. Today I will introduce to you the method of uploading images in H5 under Angular (multiple images can be uploaded). Very good, friends who need it can refer to it

The function of uploading pictures under angular was used in a recent project. I encountered many problems during the process, and they were finally solved

When uploading in angular The process is similar to the normal upload process, except that some things need to be converted into angular things.

1.ng-file-select, the instruction angular does not have this function. In fact, it is converted into a change event. Not much to say, just go to the code

angular.module('myApp')
.directive('ngFileSelect', [ '$parse', '$timeout', function($parse, $timeout) {
    return function(scope, elem, attr) {
      var fn = $parse(attr['ngFileSelect']);
      elem.bind('change', function(evt) {
        var files = [], fileList, i;
        fileList = evt.target.files;
        if (fileList != null) {
          for (i = 0; i < fileList.length; i++) {
            files.push(fileList.item(i));
          }
        }
        $timeout(function() {
          fn(scope, {
            $files : files,
            $event : evt
          });
        });
      });
    };
  }])

2. Before the service uploads the file Preview and compress image function

//上传文件预览
angular.module('myServers',[])
  .factory('fileReader', ['$q', '$log', function($q, $log) {
    var dataURItoBlob = function(dataURI) { 
      // convert base64/URLEncoded data component to raw binary data held in a string 
      var byteString; 
      if (dataURI.split(',')[0].indexOf('base64') >= 0) 
        byteString = atob(dataURI.split(',')[1]); 
      else 
        byteString = unescape(dataURI.split(',')[1]); 
      // separate out the mime component 
      var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]; 
      // write the bytes of the string to a typed array 
      var ia = new Uint8Array(byteString.length); 
      for (var i = 0; i < byteString.length; i++) { 
        ia[i] = byteString.charCodeAt(i); 
      } 
      return new Blob([ia], { 
        type: mimeString 
      }); 
    }; 
    var onLoad = function(reader, deferred, scope,file) {
      return function() {
        scope.$apply(function() {
           var img = new Image();
          //前端压缩图片
          img.onload = function(){ 
            //resize the image using canvas 
            var canvas = document.createElement("canvas"); 
            var ctx = canvas.getContext("2d"); 
            var width = img.width; 
            var height = img.height; 
            var MAX_WIDTH = width>2500 ? width/2 : 2500; 
            var MAX_HEIGHT = height>2500 ? height/2 : 2500;
            if (width > height) { 
              if (width > MAX_WIDTH) { 
                height *= MAX_WIDTH / width; 
                width = MAX_WIDTH; 
              } 
            } else { 
              if (height > MAX_HEIGHT) { 
                width *= MAX_HEIGHT / height; 
                height = MAX_HEIGHT; 
              } 
            }
            canvas.width = width ; 
            canvas.height = height; 
            ctx.drawImage(img, 0, 0, width, height); 
            var dataURL = canvas.toDataURL(&#39;image/jpeg&#39;, 1);
            var blob = dataURItoBlob(dataURL); 
            if(blob.size > 2000 * 1024){
              dataURL = canvas.toDataURL(&#39;image/jpeg&#39;, .2);
            }else if(blob.size > 1000 * 1024){
              dataURL = canvas.toDataURL(&#39;image/jpeg&#39;, .5);
            }else{
              dataURL = canvas.toDataURL(&#39;image/jpeg&#39;, .8);
            }
            blob = dataURItoBlob(dataURL);
            deferred.resolve(blob);
          }
          img.src = URL.createObjectURL(file);
        });
      };
    };
    var onError = function(reader, deferred, scope) {
      return function() {
        scope.$apply(function() {
          deferred.reject(reader.result);
        });
      };
    };
    var onProgress = function(reader, scope) {
      return function(event) {
        scope.$broadcast("fileProgress", {
          total: event.total,
          loaded: event.loaded
        });
      };
    };
    var getReader = function(deferred, scope, file) {
      var reader = new FileReader();
      reader.onload = onLoad(reader, deferred, scope,file);
      reader.onerror = onError(reader, deferred, scope);
      reader.onprogress = onProgress(reader, scope);
      return reader;
    };
    var readAsDataURL = function(file, scope) {
      var deferred = $q.defer();
      var reader = getReader(deferred, scope,file);
      reader.readAsDataURL(file);
      return deferred.promise;
    };
    return {
      readAsDataUrl: readAsDataURL
    };
  }]);

Let me explain here, part of the code is based on other people’s code (http://blog.csdn.net/zx007fack/article/details/41073601 ), but the content has been modified, because with the original code, it is normal if the front-end compression function is not added. For front-end compression, because canvas is used, you can directly use reader.result to get the width and height of the image on ios. It is directly 0, which is possible on Android. The specific reason is not sure whether it is a problem with base64, so I directly passed the file in, then used the native js method to create a new image element to get the width and height, and then used Canvas to compress it. , and finally converted into blob, passed to the background through formData.

3.controller code

//选择图片后执行的方法
    $scope.fileArr = [];
    $scope.imgSrcArr = [];var i = 0; //为ios上图片都为image时添加序号
    $rootScope.onFileSelect = function(files, event) {
      //预览上传图片开始
      $rootScope.startLoading();
      var $this = angular.element(event.target);
      angular.forEach(files, function(value, index) {
        var fileIn = value;
        var fileInName = fileIn.name;
        var fileType = fileInName.substring(fileInName.lastIndexOf(".") + 1, fileInName.length);
        //解决ios下所有图片都为image.jpg的bug
        if(fileIn) {
          fileInName = fileInName.split('.')[0] + i + '.' + fileType;
          i++;
        }
        attachvo.push({
          name: fileInName,
          type: fileType
        });
        fileReader.readAsDataUrl(fileIn, $scope)
          .then(function(result) {
            result.name = fileInName;
            $scope.fileArr.push(result);
            $scope.imgSrcArr.push(URL.createObjectURL(result));
　　　　　　　　　　　　　　//每次上传后清空file框，确保每次都能调用change事件
            document.querySelector('.upload').reset();
          });
        $scope.$on('fileProgress', function(event, data) {
          if(data.total == data.loaded) {
            $timeout(function() {
              //上传图片结束
              $rootScope.endLoading();
            }, 200)
          }
        });      
      });
      $rootScope.showAttachment = false;
    };return false;
    }

Here we process the picture and add a serial number to the name, because the name of the picture selected every time on ios is called image. I searched a lot of information and said It's a Safari bug that will be solved in later versions, so it can only be solved in this way for the time being. The loop is to upload multiple pictures

3.html code

<ul class="upload-view-ul">
    <li ng-repeat="src in imgSrcArr" class="pull-left" ng-click="delCurUpload(src)" 
      ng-class="{&#39;row-last&#39;: (($index+1) % 5==0)}">
      <span>x</span>
      <em ng-if=&#39;nrc&#39;>{{formData.attachvo[$index].attachmentType}}</em>
      <img ng-src="{{src}}">
    </li>
    <p class="attachment" pop-type-select ng-if="nrc">+</p>
    <p class="attachment" ng-if="!nrc">
      +
      <form class="upload">
        <input type="file" name="file[]" ng-file-select="onFileSelect($files, $event)" multiple>
      </form>
    </p>
  </ul>

4. By the way, paste the formdata code, using the H5 method of uploading pictures

this.FormdataPost = function(pathUrl, formId, formData, files) {
    var fd = new FormData();
    fd.append('formId', formId);
    if(files && angular.isArray(files)) {
      files.forEach(function(item) {
        fd.append('file', item, item.name);
      });
    }
    fd.append('formData', angular.toJson(formData, true));
    var httpConfig = {
      headers: {
        'Authorization': 'Bearer ' + this.token,
        'Content-Type': undefined
      },
      transformRequest: angular.identity
    };
    return $http.post(rootUrl + pathUrl, fd, httpConfig).then(function(data) {
      return data;
    }).catch(function(error) {
      $rootScope.interfaceName = pathUrl;
      $rootScope.setNewWortStatus({
        status: error.status,
        errInfo: error.data && error.data.statusInfo || ''
      });
      return error;
    });
  }

The idea is a bit confusing , I don’t know if I have made it clear, I will add it when I think of it

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