angularjs – 即使我没有显式调用$apply(),也会’获取’$apply已

我正在创建一个有助于上传CSV文件的指令.我正在使用< input type =“file”ng-hide =“true”/>和本机 JavaScript FileReader()来做到这一点.当我使用本机输入选择文件时,一切正常,但我尝试使用自己的“浏览”按钮自定义文件控件.问题是,当我尝试这样做时,我得到$apply已经在进行中错误.

这是我的指示

app.directive('skUploader',function ($timeout) {
    return {
        restrict: 'A',replace: true,template: '<div>
                    <input type="file" class="uploadControl" ng-hide="false" />
                    <input type="text" ng-model="selectedFile" />
                    <button type="button" class="btnPlain" ng-click="triggerBrowse()">Browse</button>
                    <button type="button" class="btnOrange fRight" ng-click="uploadCSV()">Upload</button>
                    <button type="button" class="btnPlain fRight" ng-click="cancel()">Cancel</button>
                   </div>',link: function (scope,elem,attr,ctrl) {

            var uploadControl = elem.find('input[type=file]');
            var payload = null;

            var type = attr.skUploader;
            scope.selectedFile = null;

            scope.uploadCSV = function () {
                $timeout(function () {
                    alert('Upload Successful');
                },3000);
            }

            scope.cancel = function () {
                payload = null;
                scope.selectedFile = null;
                scope.model.showUploadPanel = false;

            }

            uploadControl.on('change',function () {
                var fileHandle = uploadControl[0].files[0];
                var reader = new FileReader();
                var buffer;

                scope.selectedFile = fileHandle.name;

                reader.onload = function(){
                    buffer = reader.result;

                    payload = parseCSV(buffer);

                    if (payload) {
                        // Make API call
                        if (type == 'mapping') {
                            console.log(payload);
                        } else {

                        }
                    }
                }

                if (fileHandle.name.indexOf('.csv') > 0) {
                    reader.readAsText(fileHandle);
                } else {

                }

                });

            function parseCSV(buff){

                var entries = [];
                entries = buff.split(/n/);

                var json = [];


                if (type == 'mapping') {
                    var formatter = {
                        iRowNumber: null,SourceName: null,DestName: null
                    };
                } else if (type == 'passwords') {
                    var formatter = {
                        iRowNumber: null,SourceCreds: {
                            EmailAddress: null,Username: null,Pwd: null
                        }
                    };
                } else {
                    return null;
                }


                for(var i = 1; i < entries.length - 1; i++){
                    var split = entries[i].split(',');

                    var obj = angular.copy(formatter);

                    var j = 0;
                    angular.forEach(formatter,function (value,key) {
                        if (key == 'iRowNumber') {
                            obj[key] = i;
                        } else if (key == 'SourceCreds') {
                            obj[key] = {
                                EmailAddress: split[0],Username: split[1],Pwd: split[2]
                            };
                        }else{
                            obj[key] = split[j];
                            j++;
                        }
                    });

                    json.push(obj);

                }

                return json;

            }

            scope.triggerBrowse = function () {
                uploadControl.trigger('click'); // THIS IS WHAT CAUSES THE ERROR
            }
        }
    };
});

当我使用“浏览”按钮触发(‘点击’)uploadControl时,Angular会发出错误

Error: [$rootScope:inprog] $apply already in progress

但我没有使用范围.$apply()在任何地方,所以我无法弄清楚问题.它应该只是触发< input type =“file”/>上的click事件.这应该打开OS本机文件资源管理器.

更新

它可能是与this issue相关的东西吗？

更新2

经过一些研究后,我发现this Git issue vojta(一个核心的AngularJS dev)回应说我们需要将事件包装在$timeout中.我这样做了,它确实有效！有人可以向我解释为什么需要这么详细吗？谢谢