Angular下H5上传图片的方法（可多张上传）

最近做的项目中用到了angular下上传图片功能，在做的过程中遇到了许多问题，最终都得以解决

angular上传时和普通上传时过程差不多，只不过是要不一些东西转化为angular的东西。

1.ng-file-select,指令angular是没此功能的，其实也是转化成了change事件，不多说，直接上代码

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.服务 上传文件前预览并压缩图片功能

//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('image/jpeg', 1);
            var blob = dataURItoBlob(dataURL); 
            if(blob.size > 2000 * 1024){
              dataURL = canvas.toDataURL('image/jpeg', .2);
            }else if(blob.size > 1000 * 1024){
              dataURL = canvas.toDataURL('image/jpeg', .5);
            }else{
              dataURL = canvas.toDataURL('image/jpeg', .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
    };
  }]);

这里说明一下，部分代码是参考别人的代码（http://blog.csdn.net/zx007fack/article/details/41073601），但是对其中内容做了修改，因为用原来的代码，如果不加前端压缩功能是正常的，前端压缩的话因为要用到canvas, 直接用reader.result在ios上图片的宽高拿到的直接是0，android上是可以的，具体原因不是很确定是不是base64的问题，所以我又直接把file传了进来，然后用原生js的方法新建图片元素拿到宽高，再用Canvas进行压缩，最后转成blob，通过formData传给后台。

3.controller代码

//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;
    }

这里处理了下图片，在名字上加了序号，因为在ios上每次选择的图片名字都叫image,查找了很多资料，说是safari的bug,后面版本才会解决，暂时只能以这种方式解决了。循环是上传多张图片

3.html代码

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

4.顺便把formdata时代码贴一下，采用H5上传图片的方式

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;
    });
  }

思路有一点混乱，不知道讲清楚了没有，想起来再添加吧

以上所述是小编给大家介绍的Angular下H5上传图片的方法（可多张上传），希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对小牛知识库网站的支持！