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（），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; }