如何检测AngularJS中完成的所有imges加载

Question

我想用来ng-repeat在页面中显示超过100个图像.这些图像在加载时花费了大量时间,我不希望显示它们被加载到用户.所以,我只想在浏览器中加载它们之后显示它们.

如果加载了所有图像,有没有办法检测？

Answer 1

你可以使用这样的load事件.

image.addEventListener('load', function() {
       /* do stuff */ 
});

角度指令

单个图像的解决方案

HTML

<div ng-app="myapp">
    <div ng-controller="MyCtrl1">
        <loaded-img src="src"></loaded-img>
        <img ng-src="{{src2}}" />'
    </div>
</div>

JS

var myApp = angular.module('myapp',[]);
myApp
    .controller('MyCtrl1', function ($scope) {
            $scope.src = "http://lorempixel.com/800/200/sports/1/";
            $scope.src2 = "http://lorempixel.com/800/200/sports/2/";
    })
    .directive('loadedImg', function(){
        return {
            restrict: 'E',
            scope: {
                src: '='
            },
            replace: true,
            template: '<img ng-src="{{src}}" class="none"/>',
            link: function(scope, ele, attr){
                ele.on('load', function(){
                    ele.removeClass('none');
                });           
            }
        };
    });

CSS

.none{
    display: none;
}

http://jsfiddle.net/jigardafda/rqkor67a/4/

如果您看到jsfiddle演示,您会注意到src图像仅在图像完全加载后显示,而在src2您可以看到图像加载的情况下.(禁用缓存以查看差异)

多个图像的解决方案

HTML

<div ng-app="myapp">
    <div ng-controller="MyCtrl1">
        <div ng-repeat="imgx in imgpaths" ng-hide="hideall">
            <loaded-img isrc="imgx.path" onloadimg="imgx.callback(imgx)"></loaded-img>
        </div>
    </div>
 </div>

JS

var myApp = angular.module('myapp',[]);
myApp
    .controller('MyCtrl1', function ($scope, $q) {

        var imp = 'http://lorempixel.com/800/300/sports/';

        var deferred;
        var dArr = [];
        var imgpaths = [];

        for(var i = 0; i < 10; i++){
            deferred = $q.defer();
            imgpaths.push({
                path: imp + i,
                callback: deferred.resolve
            });
            dArr.push(deferred.promise);
        }

        $scope.imgpaths = imgpaths;

        $scope.hideall = true;

        $q.all(dArr).then(function(){
            $scope.hideall = false;
            console.log('all loaded')
        });
    })
    .directive('loadedImg', function(){
        return {
            restrict: 'E',
            scope: {
                isrc: '=',
                onloadimg: '&'
            },
            replace: true,
            template: '<img ng-src="{{isrc}}" class="none"/>',
            link: function(scope, ele, attr){
                ele.on('load', function(){
                    console.log(scope.isrc, 'loaded');
                    ele.removeClass('none');
                    scope.onloadimg();
                });           
            }
        };
    });

要检测是否所有图像都已加载,

对于每个图像,我生成一个deferred对象并将其deferred.resolve作为图像的onload回调传递给该deferred对象promise,然后将该对象推送到数组中.之后我常常$q.all检测所有这些承诺是否已经解决.

http://jsfiddle.net/jigardafda/rqkor67a/5/

更新:添加角度方式.

更新:添加了加载多个图像的解决方案.