我有这个结构
app/
--pages/
----pages.component.ts
--channel/
----shared/
------assignPlaylist.modal.ts
在pages.component.ts中,我有一个名为playlist的变量
export class PagesComponent {
@Input() platform: Platform;
@Output() onPlaylistsChange: EventEmitter<Playlists>;
currentPageName: string;
currentPage: Page;
pages: Array<Page>;
playlists: Playlists;
}
在assignPlaylist.modal.ts中,我创建了一个http post方法,它返回一个新的播放列表,我需要使用返回的播放列表来替换pages.component.ts中的播放列表
this.apiService.addPlaylistToPage(playlistId, stDate, etDate, this.apiService.getGlobalRegion(), callback)
.subscribe(
data => {
if (this.apiService.g_platform == 'DESKTOP') {
this.apiService.getPlaylist(this.apiService.getCurrentPage(), 'true' )
.subscribe(
res => { this.pagesService.setCurrentPlaylists(res.playlists);
}
);
} else {
this.apiService.getPlaylist(this.apiService.getCurrentPage(), 'false' )
.subscribe(
res => { this.pagesService.setCurrentPlaylists(res.playlists);
}
);
}
}
);
这是播放列表的结构
export class Playlists {
headerPlaylists: Array<Playlist>;
bodyPlaylists: Array<Playlist>;
wholePlaylists: Array<Playlist>;
}
----------------更新---------------------- 正如答案中提到的,我做了以下更改。
@Injectable()
export class PagesService {
private currentPlaylists: Subject<Playlists> = new BehaviorSubject<Playlists>(new Playlists());
getCurrentPlaylists() {
return this.currentPlaylists.asObservable();
}
setCurrentPlaylists(playlists: Playlists) {
console.log('i am here');
this.currentPlaylists.next(playlists);
}
}
控制台显示“我在这里”,
我写在我的pages.component.ts
constructor(private service: PagesService, private playlistService: PlaylistService) {
this.pages = [];
this.currentPage = new Page();
this.service.setCurrentPage(this.currentPage);
this.playlists = new Playlists();
this.onPlaylistsChange = new EventEmitter<Playlists>();
this.service.getCurrentPlaylists().subscribe((playlists) => {
console.log(playlists, 'new playlists coming');
this.playlists = playlists;
}, error => {
console.log(error);
});
}
但是,我没有看到“新播放列表即将到来”的消息,我是否使用错误?
新更新: 我检查了this.playlists,它的观察者是0,为什么?
最佳答案
创建一个 PlaylistService 来公开 PagesComponent 可以订阅的可观察对象。
import { Injectable} from '@angular/core';
import { Subject,BehaviorSubject } from 'rxjs';
import {Playlists} from 'channel' /** Assumes this is where you have defined your Playlists interface **/
@Injectable()
export class PlaylistService {
private _currentPlaylists$: Subject<Playlists> = new BehaviorSubject<Playlists>(null);
constructor() {}
currentPlaylists() {
return this._currentPlaylists$.asObservable();
}
setCurrentPlaylists(playlists:Playlists){
this._currentPlaylists$.next(playlists);
}
}
然后将此服务导入到您的页面组件中并订阅播放列表,如下所示:-
this.playlistService.currentPlaylists().subscribe((playlists) => {
this.playlists = playlists;
},error => {
console.log(error);
});`
请记住,您还必须将此服务导入到您的 allocatePlaylistModal 中并按如下方式使用它:-
this.apiService.addPlaylistToPage(playlistId, stDate, etDate, this.apiService.getGlobalRegion(), callback)
.subscribe(
data => {
if (this.apiService.g_platform == 'DESKTOP') {
this.apiService.getPlaylist(this.apiService.getCurrentPage(), 'true' )
.subscribe(
res => {
this.playListService.setCurrentPlaylists(res);
}
);
} else {
this.apiService.getPlaylist(this.apiService.getCurrentPage(), 'false' )
.subscribe(
res => {
this.playListService.setCurrentPlaylists(res);
}
);
}
}
);
请阅读有关可观察量的更多信息,以了解为什么在这里使用 BehaviourSubject。 http://reactivex.io/documentation/observable.html
关于javascript - 在 Angular2 中使用可观察的与其他组件的对话,不接收即将到来的值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38881264/