javascript - 使用angularjs提取字节数组中的多个文件内容

Question

我正在使用此解决方案将文件解析为字节数组:
这对我有用。
但我想对多个文件执行此操作

var pniotApp = angular.module('pniotApp', []);

pniotApp.controller('pniotCtrl', function ($scope, $http, $location) {
    $scope.saveContent = function ($fileContent) {
        $scope.content = $fileContent;
        console.log($scope.content);
    };
});

pniotApp.directive('onReadFile', function ($parse) {
    return {
        restrict: 'A',
        scope: false,
        link: function (scope, element, attrs) {
            var fn = $parse(attrs.onReadFile);
            element.on('change', function (onChangeEvent) {
                var reader = new FileReader();
                reader.onload = function (onLoadEvent) {
                    var buffer = onLoadEvent.target.result;
                    var uint8 = new Uint8Array(buffer);     
                    var result = [];
                    for (var i = 0; i < uint8.length; i++) {
                        result.push(uint8[i]);
                    }

                    scope.$apply(function () {
                        fn(scope, {
                            $fileContent: result
                        });
                    });
                };
                
                  reader.readAsArrayBuffer((onChangeEvent.srcElement || onChangeEvent.target).files[0]);
            });
        }
    };
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<input on-read-file="saveContent($fileContent)" type="file"/>

现在我想对多个文件执行此操作。我尝试替换行 reader.readAsArrayBuffer((onChangeEvent.srcElement || onChangeEvent.target).files[0]);
与:

 for (j = 0; j < (onChangeEvent.srcElement || onChangeEvent.target).files.length;j++)
                reader.readAsArrayBuffer((onChangeEvent.srcElement || onChangeEvent.target).files[j]);

但我收到此错误
Uncaught DOMException: 无法在“FileReader”上执行“readAsArrayBuffer”:该对象已忙于读取 Blob。

Answer 1

Failed to execute 'readAsArrayBuffer' on 'FileReader': The object is already busy reading Blobs.

我认为这是正确的行为。您应该一个接一个地读取文件并重新创建 Reader a.e.

var reader = new FileReader();

所以相反:

for (j = 0; j < (onChangeEvent.srcElement || onChangeEvent.target).files.length;j++)
   reader.readAsArrayBuffer((onChangeEvent.srcElement || onChangeEvent.target).files[j]);

应该是这样的:

 var files = (onChangeEvent.srcElement || onChangeEvent.target).files;
for (j = 0; j < files.length;j++){
    readerEngine(files[j]);
    }

其中readerEngine是:

function readerEngine(file_){
  var reader = new FileReader();
  reader.onload = function (onLoadEvent) {
      var buffer = onLoadEvent.target.result;
      var uint8 = new Uint8Array(buffer);     
      var result = [];
      for (var i = 0; i < uint8.length; i++) {
           result.push(uint8[i]);
       }

       scope.$apply(function () {
           fn(scope, {
              $fileContent: result
           });
         });
   };

   reader.readAsArrayBuffer(file_);
}

<小时/>

没有测试