我的 angularjs 应用程序遇到异步问题。
我想要做的是从远程服务器检索数据(在 prefsService.js 中)。然后将数据的值分配给 Controller 中的变量(在 prefsController.js 中)。
这是 prefsService.js 文件:
(function() {
'use strict';
angular
.module('app')
.factory('PrefsService', PrefsService);
PrefsService.$inject = ['$resource','PrefsResource'];
function PrefsService($resource,PrefsResource) {
var initialize = function() {
var twentyFourHourTime = null;
var decimalTime = null;
var startDayOfWeek = null;
var roundingOption = null;
var roundingIncrement = null;
PrefsResource.get({key:"TwentyFourHourTime"}, function(data) {
if (data.result.value === null||undefined) {
twentyFourHourTime = 0;
} else {
twentyFourHourTime = data.result.value;
}
PrefsResource.get({key:"DecimalTime"}, function(data) {
if (data.result.value === null||undefined) {
decimalTime = 0;
} else {
decimalTime = data.result.value;
}
PrefsResource.get({key:"startDayOfWeek"}, function(data) {
if (data.result.value === null||undefined) {
startDayOfWeek = 0;
} else {
startDayOfWeek = data.result.value;
}
return {"twentyFourHourTime":twentyFourHourTime,"decimalTime":decimalTime,"startDayOfWeek":startDayOfWeek}
});
});
});
};
return {
initialize: initialize
};
}
})();
这是 prefsController.js 文件:
vm.test=PrefsService.initialize();
console.log('Prefs data initialized', vm.test);
当我运行它时，vm.test 总是“未定义”。
我该怎么办？谢谢!
最佳答案
我还没有对此进行语法检查，但它的要点是 promise ，就像所有异步编程一样。这个问题是一个骗子(谁能再找到此类问题的主要骗子？)但以下是如何使用 Angular 来做到这一点:
(function() {
'use strict';
angular
.module('app')
.factory('PrefsService', PrefsService);
PrefsService.$inject = ['$resource','PrefsResource'];
function PrefsService($resource,PrefsResource) {
var initialize = function() {
//return a promise
return $q
.all([
PrefsResource.get({key:"TwentyFourHourTime"}),
PrefsResource.get({key:"DecimalTime"}),
PrefsResource.get({key:"startDayOfWeek"})
])
.then(function(values) {
var
twentyFourHourTime = values[0],
decimalTime = values[1],
startDayOfWeek = values[2];
//return the value (object) when all promises have resolved
return {
"twentyFourHourTime":twentyFourHourTime.result.value || 0,
"decimalTime":decimalTime.result.value || 0,
"startDayOfWeek":startDayOfWeek.result.value || 0
}
})
}
return {
initialize: initialize
};
}
})();
PrefsService
.initialize()
//use the promise API to log messages only after the promise has resolved
.then(function(prefs) {
console.log('initialized');
console.log(prefs);
})
关于javascript - AngularJS 中的异步数据检索，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34139028/