[英]AngularFire 0.5.0 $on 'change' event not firing correctly
Let's say I have a collection of articles I am trying to paginate through. 假设我有一些我想翻阅的文章。
I'm using the $on("change")
event to listen for changes to index
and limit
我正在使用$on("change")
事件来监听对index
和limit
更改
.controller('articlesCtrl', ["$scope", "$firebase", "$stateParams", function($scope, $firebase, $stateParams) {
var limit = 2;
var index = $stateParams.id;
var articlesRef = new Firebase("https://example.firebaseio.com/articles").startAt(null, index).limit(limit);
var obj = $firebase(articlesRef);
obj.$on("change", function() {
var keys = obj.$getIndex();
index = keys[keys.length-1];
console.log(obj);
});
$scope.update = function(){
limit = limit + 2;
obj = $firebase(articlesRef.startAt(null, index).limit(limit));
}
}]);
What I'm noticing - is on initial load the $on("change")
event fires twice. 我要注意的是-在初始加载时 , $on("change")
事件会触发两次。
And every subsequent call to update the index
or limit
does not fire the $on("change")
event. 并且随后每次更新index
或limit
调用都不会触发$on("change")
事件。
<button type="button" ng-click="update();">Update</button>
Each time $scope.update fires, you assign the obj
variable to a new reference. 每次触发$ scope.update时,您就将obj
变量分配给一个新引用。 However, you only attach obj.$on(change)
to the original obj
. 但是,您只能将obj.$on(change)
附加到原始obj
。
This could probably be optimized with some experimentation; 可以通过一些实验来优化它。 here's a quick brute force to get you started: 这是一种快速的蛮力帮助您入门:
var limit = 2;
var index = $stateParams.id;
var articlesRef = new Firebase("https://example.firebaseio.com/articles");
$scope.update = update;
update(); // initialize
function update(){
limit = limit + 2;
var obj = $firebase(articlesRef.startAt(null, index).limit(limit));
obj.$on("loaded", function() {
var keys = obj.$getIndex();
index = keys[keys.length-1];
console.log(obj);
});
}
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