最近要實現一個多圖片上傳的預覽功能,網上有很多例子大多不太完整,我就把他們的整合了下並且加了一些功能和界面,我們只需要調用一條指令就可以實現,但傳給後臺還需要額外的代碼,會在後面controller裏介紹。不知道封裝的是否符合標準,還希望大家一起討論下,如果有時間封裝下Angular4的圖片上傳和預覽分享給大家
圖片上傳的預覽,我們最主要解決的是拿到input的on-change事件,再是讀取圖片,讀取圖片我們需要用到FileReader。
我們先寫一個讀取圖片的服務,這是網上的一位大佬寫的,我就直接拿了過來
/**
* 圖片上傳獲取返回的url
*/
app .factory('fileReader', ["$q", "$log", function($q, $log){
var onLoad = function(reader, deferred, scope) {
return function () {
scope.$apply(function () {
deferred.resolve(reader.result);
});
};
};
var onError = function (reader, deferred, scope) {
return function () {
scope.$apply(function () {
deferred.reject(reader.result);
});
};
};
var getReader = function(deferred, scope) {
var reader = new FileReader(); //fileReader
reader.onload = onLoad(reader, deferred, scope);
reader.onerror = onError(reader, deferred, scope);
return reader;
};
var readAsDataURL = function (file, scope) {
var deferred = $q.defer();
var reader = getReader(deferred, scope);
reader.readAsDataURL(file);
return deferred.promise;
};
return {
readAsDataUrl: readAsDataURL
};
}])
我們現在有了圖片的讀取,我們再來搞定圖片的on-change事件
/**
* 圖片上傳預覽
*/
app .directive('file', ['$parse', 'fileReader', function ($parse, fileReader) {
return {
restrict: 'A',
link: function(scope, element, attrs, ngModel) {
var model = $parse(attrs.file);
var modelSetter = model.assign;
console.log(modelSetter)
element.bind('change', function(event){
scope.$apply(function(){
modelSetter(scope, element[0].files[0]);
});
//附件預覽
scope.imgupload = (event.srcElement || event.target).files[0];
getFile(scope.imgupload, scope);
//獲得預覽圖地址並且把file對象放入上傳合集內
function getFile (imgupload, scope) {
if(!imgupload) {
return;
}
fileReader.readAsDataUrl(imgupload, scope)
.then(function(result) {
scope.imgshows.push(result)
var file = document.querySelector('input[type=file]').files[0];
scope.uploadimgs.push(file)//這裏是放着傳給後臺的數據file,下面controller的時候會有
});
};
});
}
};
}])
這裏就是提供上傳圖片預覽的樣式,還有預覽圖刪除的功能
app .directive('uploadimg', function () {
return {
restrict: 'E',
scope: {
uploadimgs: "="
},
templateUrl: './js/directives/uploadimg/uploadimg.html',
link: function(scope, element, attrs) {
scope.imgshows = []//預覽圖片合集放的是src
scope.uploadimg_del = function(index,imgs) {
scope.imgshows.splice(index,1);
scope.uploadimgs.splice(index,1);
}
}
}
})
<style type="text/css">
.fileupload {
width: 100px;
height: 100px;
border: 1px dotted #ccc;
display: inline-block;
}
.fileupload-icon {
font-size:32px;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}
</style>
<div>
<div class="fileupload pos-rlt" ng-repeat="imageSrc in imgshows">
<img ng-src="{{imageSrc}}" style="max-width:200px;max-height:300px;margin:0 auto; display:block;" class="pos-rlt" width=100%; height=100%;/>
<i class="icon ion-close-circled" style="position: absolute; top:5px; right: 5px" ng-click="uploadimg_del($index, imgshows)"></i>
</div>
<div class="fileupload pos-rlt clear" >
<i class="icon ion-plus-round fileupload-icon"></i>
<input type="file" style="display:inline-block; width: 100%; height: 100%; opacity:0" name="upload_img" file="upload_img" placeholder="選擇圖片" accept="image/png,image/gif,image/jpeg,image/jpg" >
</div>
</div>
</label>
最後的調用也很簡單
我們只需要在2個地方加代碼一個是在界面,一個是在Controller裏
<uploadimg uploadimgs="uploadimgs"></uploadimg>
這個是在Controller裏的,這是用來傳給後臺的數據集合,我們需要傳給後臺的是file對象
$scope.uploadimgs = []//上傳圖片合集放的是file對象
如何傳給後臺呢,直接附上代碼,其實不難
$scope.save = function() {
var Fromdata = {
'name': $scope.form.name,
'desc': $scope.form.descr,
'price': $scope.form.price,
'status': $scope.form.status?1:0,
}
var uploadData = createFromData(Fromdata)
for(var i = 0; i < $scope.uploadimgs.length; i++) {
uploadData.append('upload_imgs', $scope.uploadimgs[i])
}
$http({
method:'POST',
url:"後臺地址",
data: fd,
headers: {'Content-Type':undefined},
transformRequest: angular.identity
})
.success( function(response){
//上傳成功的操作
});
}
//構造FormData
//@param 是一個對象
function createFromData(Fromdata) {
var fd = new FormData();
for(key in Fromdata) {
fd.append(key,Fromdata[key]);
}
return fd
}
最後給大家看下預覽圖
大家發現什麼問題一起討論~~~~