AngularJS 服务
在 AngularJS 中，您可以创建自己的服务，也可以使用许多内置服务之一。
什么是服务？
在 AngularJS 中，服务是一个函数或对象，它可以供您的 AngularJS 应用程序使用，并且仅限于您的 AngularJS 应用程序。
AngularJS 拥有大约 30 个内置服务。其中之一是 $location 服务。
$location 服务具有可返回有关当前网页位置信息的函数。
示例
在控制器中使用 $location 服务
var app = angular.module('myApp', []);
app.controller('customersCtrl', function($scope, $location) {
$scope.myUrl = $location.absUrl();
});
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请注意，$location 服务作为参数传递给控制器。为了在控制器中使用该服务，必须将其定义为依赖项。
为什么要使用服务？
对于许多服务，例如 $location 服务，您可能会认为可以使用 DOM 中已有的对象，如 window.location 对象，而您确实可以这样做，但这会带来一些限制，至少对您的 AngularJS 应用程序是这样。
AngularJS 会持续监督您的应用程序，并且为了正确处理更改和事件，AngularJS 更倾向于您使用 $location 服务而不是 window.location 对象。
The $http Service
The $http service is one of the most common used services in AngularJS applications. The service makes a request to the server, and lets your application handle the response.
示例
Use the $http service to request data from the server
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope, $http) {
$http.get("welcome.htm").then(function (response) {
$scope.myWelcome = response.data;
});
});
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This example demonstrates a very simple use of the $http service. Learn more about the $http service in the AngularJS Http Tutorial.
The $timeout Service
The $timeout service is AngularJS' version of the window.setTimeout function.
示例
Display a new message after two seconds
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope, $timeout) {
$scope.myHeader = "Hello World!";
$timeout(function () {
$scope.myHeader = "How are you today?";
}, 2000);
});
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The $interval Service
The $interval service is AngularJS' version of the window.setInterval function.
示例
Display the time every second
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope, $interval) {
$scope.theTime = new Date().toLocaleTimeString();
$interval(function () {
$scope.theTime = new Date().toLocaleTimeString();
},
1000);
});
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Create Your Own Service
To create your own service, connect your service to the module
Create a service named hexafy
app.service('hexafy', function() {
this.myFunc = function (x) {
return x.toString(16);
}
});
To use your custom made service, add it as a dependency when defining the controller
示例
Use the custom made service named hexafy to convert a number into a hexadecimal number
app.controller('myCtrl', function($scope, hexafy) {
$scope.hex = hexafy.myFunc(255);
});
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Use a Custom Service Inside a Filter
Once you have created a service, and connected it to your application, you can use the service in any controller, directive, filter, or even inside other services.
To use the service inside a filter, add it as a dependency when defining the filter
The service hexafy used in the filter myFormat
app.filter('myFormat',['hexafy', function(hexafy) {
return function(x) {
return hexafy.myFunc(x);
};
}]);
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You can use the filter when displaying values from an object, or an array
<ul>
<li ng-repeat="x in counts">{{x | myFormat}}</li>
</ul>
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