在页面滚动懒加载角视图和控制器 [英] Lazy loading Angular views and controllers on page scroll
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问题描述
我有一个利用Laravel和角度的微型。这是一个页面的微型的响应，并分成5个部分。我想偷懒加载它们，以减少加载的一次。
I have a microsite that is utilizing Laravel and Angular. It's a one page microsite that is responsive and is broken into 5 sections. I would like to lazy load them to cut down on loading all at once.
<body ng-app>
<div id="wrapper">
<section id="intro">1</section>
<section id="Second">2</section>
<section id="Third">3</section>
<section id="Fourth">4</section>
<section id="Fifth">5</section>
</div>
</body>
我期待装载1安培; 2在页面加载，然后当你向下滚动页面加载其他视图在一个不错的渐渐然后加载其互动项目。
I'm looking to load 1 & 2 on page load then as you scroll down the page load the other view with a nice fade in and then load its interactive items.
推荐答案
在这种情况下，它可能是没有必要的（或有效的），以延迟加载你的控制器，但它可以做到的。
In this case it is probably not necessary (or efficient) to lazy load your controllers, but it can be done.
有很多事情要处理在这里，所以我会处理它的部分。
There are many things to tackle here, so I'm going to handle it in sections.
标记：
<div class="container">
<section
ng-repeat="section in loadedSections"
ng-include="section+'.html'"
scroll-load
scroll-load-from="sections"
scroll-load-to="loadedSections"
ng-animate="{enter:'section-animate-enter'}"
></section>
</div>
动画CSS：
.section-animate-enter {
-webkit-transition: 1.5s linear all;
transition: 1.5s linear all;
opacity: 0;
left: 100%;
}
.section-animate-enter.section-animate-enter-active {
opacity: 1;
left: 0;
}
角逻辑：
app.controller('myCtrl', function($scope) {
$scope.sections = ['top','mid','bottom']; //html files to load (top.html, etc)
$scope.loadedSections = [$scope.sections[0]]; //loaded html files
});
app.directive('scrollLoad', function($compile) {
return {
restrict: 'A',
link: function(scope, element, attrs) {
var to = scope[attrs.scrollLoadTo]; //$scope.loadedSections
var from = scope[attrs.scrollLoadFrom]; //$scope.sections
$window = angular.element(window);
$window.bind('scroll', function(event) {
var scrollPos = document.body.scrollTop + document.documentElement.clientHeight;
var elemBottom = element[0].offsetTop + element.height();
if (scrollPos >= elemBottom) { //scrolled to bottom of scrollLoad element
$window.unbind(event); //this listener is no longer needed.
if (to.length < from.length) { //if there are still elements to load
//use $apply because we're in the window event context
scope.$apply(to.push(from[to.length])); //add next section
}
}
});
}
};
});
延迟加载控制器上和滚动视图（动画）。
标记：
<div class="container">
<!-- the "lazy" directive will get the controller first, then add ng-include -->
<section
ng-repeat="section in loadedSections"
lazy="section"
scroll-load
scroll-load-from="sections"
scroll-load-to="loadedSections"
ng-animate="{enter:'section-animate-enter'}"
></section>
</div>
角逻辑：
var $appControllerProvider; //see below
var app = angular.module('myApp', []);
app.config(function($controllerProvider) {
$appControllerProvider = $controllerProvider; //cache this so that we can lazy load controllers
});
app.controller('myCtrl', function($scope) {
$scope.sections = ['top','mid','bottom']; //html files to load (top.html, etc)
$scope.loadedSections = [$scope.sections[0]]; //loaded html files
});
app.directive('scrollLoad', function($compile) {
return {
restrict: 'A',
link: function(scope, element, attrs) {
var to = scope[attrs.scrollLoadTo]; //$scope.loadedSections
var from = scope[attrs.scrollLoadFrom]; //$scope.sections
$window = angular.element(window);
$window.bind('scroll', function(event) {
var scrollPos = document.body.scrollTop + document.documentElement.clientHeight;
var elemBottom = element[0].offsetTop + element.height();
if (scrollPos >= elemBottom) { //scrolled to bottom of scrollLoad element
$window.unbind(event); //this listener is no longer needed.
if (to.length < from.length) { //if there are still elements to load
//use $apply because we're in the window event context
scope.$apply(to.push(from[to.length])); //add next section
}
}
});
}
};
});
app.factory('myService', function($http, $q) {
return {
getController: function(fileName) {
return $http.get(fileName+'.js').then(function(response) {
return response.data;
});
}
}
});
app.directive('lazy', function(myService, $compile, $q) {
/* I store the directive in a variable then return it later
* so that I can abstract directive logic into other functions below */
var directiveReturn = {
restrict: 'A',
link: function(scope, element, attrs) {
var loadName = scope.$eval(attrs.lazy);
//this is straightforward - see the "addScript" function for explanation
myService.getController(loadName).then(function(js) {
return addScript(loadName, js, scope);
}).then(function() {
//the controller has been lazy loaded into angular
//now use "ng-include" to lazy load the view.
var ngInc = angular.element('<span></span>')
.attr('ng-include', "'"+loadName+".html'")
.attr('ng-controller', loadName+'Ctrl');
element.append(ngInc);
$compile(ngInc)(scope);
});
} //link
}; //directive return
/*
* This is the magic.
*/
var scriptPromises = {};
function addScript(loadName, js, scope) {
if (!scriptPromises[loadName]) { //if this controller hasn't already been loaded
var deferred = $q.defer();
//cache promise (which caches the controller when resolved)
scriptPromises[loadName] = deferred.promise;
//inject controller into a script tag
var script = document.createElement('script');
script.src = 'data:text/javascript,' + encodeURI(js);
script.onload = function() {
//this is how you lazy load a controller
$appControllerProvider.register(loadName, window[loadName+'Ctrl']);
//now that the controller is registered with angular, resolve the promise
//then, it is safe to add markup that uses this controller with ng-controller
scope.$apply(deferred.resolve());
};
//when this script loads, the controller will be registered and promise is resolved
document.body.appendChild(script);
return deferred.promise;
}
else { //controller already loaded
return scriptPromises[loadName]; //use cached controller
}
}
return directiveReturn;
});
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