我正在使用离子beta框架进行移动开发,它使用Angular2,所以我认为这更像是一个Angular2问题,因为它更多地涉及使用提供程序进行HTTP调用。
我的应用程序从app.js开始。在这个文件中,我调用我的提供者进行HTTP调用以在后台获取一些信息。当发生这种情况时,用户离开app.js并转到另一个页面page.js.在后台,http呼叫仍在进行并且已完成。页面应显示来自提供程序的数据,但数据尚未准备好。我是Angular的新手,我不确定如何处理这种情况。在我的页面中,如何调用我的提供程序,检查调用的状态(查看数据是否准备就绪,是否发生错误,或者是否进行了调用),并获取数据是否已准备好?
我的app.js:
import {App, Platform} from 'ionic-angular';
import {TabsPage} from './pages/tabs/tabs';
import {FacebookFriends} from './providers/facebook-friends/facebook-friends';
@App({
template: '<ion-nav [root]="rootPage"></ion-nav>',
providers: [FacebookFriends],
config: {} // http://ionicframework.com/docs/v2/api/config/Config/
})
export class MyApp {
static get parameters() {
return [[Platform]];
}
constructor(platform:Platform,facebookFriends:FacebookFriends) {
this.rootPage = TabsPage;
this.fb = facebookFriends;
platform.ready().then(() => {
this.fb.load().then((success)=>{
if(success){
console.log('success = ' + JSON.stringify(success));
}
},
(error)=>{
console.log('Error loading friends : ' + JSON.stringify(error));
});
});
}
}
我的提供商:
import {Injectable, Inject} from 'angular2/core';
import {Http} from 'angular2/http';
/*
Generated class for the FacebookFriends provider.
See https://angular.io/docs/ts/latest/guide/dependency-injection.html
for more info on providers and Angular 2 DI.
*/
@Injectable()
export class FacebookFriends {
constructor(@Inject(Http) http) {
this.http = http;
this.data = null;
}
load() {
if (this.data) {
// already loaded data
return Promise.resolve(this.data);
}
// don't have the data yet
return new Promise(resolve => {
// We're using Angular Http provider to request the data,
// then on the response it'll map the JSON data to a parsed JS object.
// Next we process the data and resolve the promise with the new data.
var headers = new Headers();
// headers.append('Content-Type', 'application/json');
headers.append('Content-Type', 'application/x-www-form-urlencoded');
this.http.post(
'http://192.168.1.45:3000/testrestapi',
{headers: headers}
).map((res => res.json())
.subscribe(data => {
// we've got back the raw data, now generate the core schedule data
// and save the data for later reference
this.data = data;
console.log('Friends Provider was a success!');
console.log(JSON.stringify(data));
resolve(this.data);
},
(err)=>{
console.log('Error in Friends Provider!');
},
()=>{
console.log('Friends Provider network call has ended!');
});
});
}
}
我的页面:
import {Page} from 'ionic-angular';
import {FacebookFriends} from '../../providers/facebook-friends/facebook-friends';
@Page({
templateUrl: 'build/pages/page1/page1.html'
})
export class Page1 {
constructor(platform:Platform,facebookFriends:FacebookFriends) {
this.rootPage = TabsPage;
this.fb = facebookFriends;
}
}
答案 0 :(得分:0)
您应该使用具有Observable类型的属性的共享服务:
export class SharedService {
dataReadyNotifier: Observer;
dataReadyObservable: Observable;
constructor() {
this.dataReadyObservable = Observable.create((observer) => {
this.dataReadyNotifier = observer;
});
}
notifyDataReady(data) {
this.dataReadyNotifier.next(data);
}
}
当数据存在于promise回调中时,将调用该服务的notifyDataReady方法。
要收到通知,组件将以这种方式在服务上注册:
export class SomeComponent {
constructor(private sharedService: SharedService) {
this.sharedService..dataReadyObservable.subscribe((data) => {
// Do something with data
});
}
(...)
}