我有一个服务,说:
factory('aService', ['$rootScope', '$resource', function ($rootScope, $resource) {
var service = {
foo: []
};
return service;
}]);
我想用foo来控制一个在HTML中呈现的列表:
<div ng-controller="FooCtrl">
<div ng-repeat="item in foo">{{ item }}</div>
</div>
以便控制器检测aService。我已经拼凑了这个模式,其中我添加aService到控制器的$scope,然后使用$scope.$watch():
function FooCtrl($scope, aService) {
$scope.aService = aService;
$scope.foo = aService.foo;
$scope.$watch('aService.foo', function (newVal, oldVal, scope) {
if(newVal) {
scope.foo = newVal;
}
});
}
这感觉有点冗长,我一直在每个使用服务变量的控制器中重复这一点。有没有更好的方法来监视共享变量?
我使用类似的方法@dtheodot,但使用角承诺而不是传递回调
app.service('myService', function($q) {
var self = this,
defer = $q.defer();
this.foo = 0;
this.observeFoo = function() {
return defer.promise;
}
this.setFoo = function(foo) {
self.foo = foo;
defer.notify(self.foo);
}
})
然后只要使用myService.setFoo(foo)方法来更新服务上的foo。在你的控制器中,你可以这样使用它:
myService.observeFoo().then(null, null, function(foo){
$scope.foo = foo;
})
then的前两个参数是成功和错误回调,第三个参数是通知回调。
$q的参考。
当我面对一个非常相似的问题时,我观察了一个作用域中的函数,并让函数返回服务变量。我已经创建了一个js小提琴。您可以在下面找到代码。
var myApp = angular.module("myApp",[]);
myApp.factory("randomService", function($timeout){
var retValue = {};
var data = 0;
retValue.startService = function(){
updateData();
}
retValue.getData = function(){
return data;
}
function updateData(){
$timeout(function(){
data = Math.floor(Math.random() * 100);
updateData()
}, 500);
}
return retValue;
});
myApp.controller("myController", function($scope, randomService){
$scope.data = 0;
$scope.dataUpdated = 0;
$scope.watchCalled = 0;
randomService.startService();
$scope.getRandomData = function(){
return randomService.getData();
}
$scope.$watch("getRandomData()", function(newValue, oldValue){
if(oldValue != newValue){
$scope.data = newValue;
$scope.dataUpdated++;
}
$scope.watchCalled++;
});
});
您可以在工厂内部观察更改,然后广播更改
angular.module('MyApp').factory('aFactory', function ($rootScope) {
// Define your factory content
var result = {
'key': value
};
// add a listener on a key
$rootScope.$watch(function () {
return result.key;
}, function (newValue, oldValue, scope) {
// This is called after the key "key" has changed, a good idea is to broadcast a message that key has changed
$rootScope.$broadcast('aFactory:keyChanged', newValue);
}, true);
return result;
});
然后在你的控制器中:
angular.module('MyApp').controller('aController', ['$rootScope', function ($rootScope) {
$rootScope.$on('aFactory:keyChanged', function currentCityChanged(event, value) {
// do something
});
}]);
通过这种方式,您将所有相关的工厂代码放在其描述中,然后您只能依赖来自外部的广播
有点丑,但我已经为切换添加了范围变量的注册到我的服务:
myApp.service('myService', function() {
var self = this;
self.value = false;
self.c2 = function(){};
self.callback = function(){
self.value = !self.value;
self.c2();
};
self.on = function(){
return self.value;
};
self.register = function(obj, key){
self.c2 = function(){
obj[key] = self.value;
obj.$apply();
}
};
return this;
});
然后在控制器中:
function MyCtrl($scope, myService) {
$scope.name = 'Superhero';
$scope.myVar = false;
myService.register($scope, 'myVar');
}