本文實例講述了AngularJS中的promise用法。分享給大家供大家參考，具體如下：
JavaScript異步回調有好處也有壞處，回調函數(shù)大量嵌套十分復雜．所以javascript中還有另一種異步處理模式叫promises．在AngularJS中的實現(xiàn)就是$q服務．
下面是一些小例子．
then,catch,finally
在鏈最后的 catch 為整個鏈式處理提供一個異常處理點
在鏈最后的 finally 總是會被執(zhí)行，不管 promise 被處理或者被拒絕，起清理作用
<!DOCTYPE html><html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > <script src="jQuery.min.js"></script> <script src="angular.min.js"></script> <script src="bootstrap.min.js"></script> <script type="text/javascript"> var myapp = angular.module('myapp', []); myapp.controller('myController', function($scope, $q) { $scope.send = function() { var deferred = $q.defer(); var promise = deferred.promise; promise .then(function() { console.log('resolve.....') }, function() { console.log('reject.....'); }, function() { console.log('notify.....'); }) .catch(function() { console.log('catch..error..') }) .finally(function() { console.log('anywhere will be called..'); }); deferred.reject('resolve'); }; }); </script> <style type="text/css"> </style> </head> <body ng-app="myapp"> <div ng-controller="myController"> <button class="btn" ng-click="send()">click</button> </div> </body></html>then第三個參數(shù)(表征狀態(tài))的應用
<!DOCTYPE html><html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > <script src="jquery.min.js"></script> <script src="angular.min.js"></script> <script src="bootstrap.min.js"></script> <script type="text/javascript"> var myapp = angular.module('myapp', []); myapp.controller('myController', function($scope, dataService) { $scope.send = function() { dataService.getData() .then(function success(data) { console.log(data); }, function error(error) { console.log(error); }, function status(process) { console.log(process); }); }; }); myapp.factory('dataService', function($q, $interval) { return { getData : function() { var deferred = $q.defer(); var process = 0; var interval = $interval(function() { process += 10; deferred.notify(process); //reject之后不再繼續(xù)運行 // if (process == 50) { // deferred.reject(process); // } if (process >= 100) { $interval.cancel(interval); deferred.resolve(process); } }, 1000); return deferred.promise; } }; }); </script> <style type="text/css"> </style> </head> <body ng-app="myapp"> <div ng-controller="myController"> <button class="btn" ng-click="send()">click</button> </div> </body></html>then鏈式
<!DOCTYPE html><html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > <script src="jquery.min.js"></script> <script src="angular.min.js"></script> <script src="bootstrap.min.js"></script> <script type="text/javascript"> var myapp = angular.module('myapp', []); myapp.controller('myController', function($scope, $q) { $scope.send = function() { var deferred = $q.defer(); var promise = deferred.promise; promise .then(function() { console.log('1.....') }) .then(function() { console.log('2....'); }); deferred.resolve('resolve'); }; }); </script> <style type="text/css"> </style> </head> <body ng-app="myapp"> <div ng-controller="myController"> <button class="btn" ng-click="send()">click</button> </div> </body></html>then鏈會把上一個 then 的返回結果傳遞給調用鏈的下一個 then (如果沒有就是 undefined).
<!DOCTYPE html><html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" > <script src="jquery.min.js"></script> <script src="angular.min.js"></script> <script src="bootstrap.min.js"></script> <script type="text/javascript"> var myapp = angular.module('myapp', []); myapp.controller('myController', function($scope, $q, $timeout) { $scope.send = function() { var deferred = $q.defer(); var promise = deferred.promise; deferred.resolve('resolve'); promise .then(function(data) { console.log(data); var _deferred = $q.defer(); $timeout(function() { _deferred.resolve('resolve_'); }, 1000); return _deferred.promise; }) .then(function(data) { console.log(data); }); }; }); </script> <style type="text/css"> </style> </head> <body ng-app="myapp"> <div ng-controller="myController"> <button class="btn" ng-click="send()">click</button> </div> </body></html>如果 then 返回一個 promise 對象，下一個 then 只會在這個 promise 被處理結束的時候調用。
更多關于AngularJS相關內容感興趣的讀者可查看本站專題：《AngularJS指令操作技巧總結》、《AngularJS入門與進階教程》及《AngularJS MVC架構總結》
希望本文所述對大家AngularJS程序設計有所幫助。
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