[英]Using observable talk to other component in angular2, not receiving coming value
我有這個教練
app/
--pages/
----pages.component.ts
--channel/
----shared/
------assignPlaylist.modal.ts
在pages.component.ts中,我有一個名為播放列表的變量
export class PagesComponent {
@Input() platform: Platform;
@Output() onPlaylistsChange: EventEmitter<Playlists>;
currentPageName: string;
currentPage: Page;
pages: Array<Page>;
playlists: Playlists;
}
在assignPlaylist.modal.ts中,我創建了一個http post方法,它返回了一個新的播放列表,我需要使用返回的播放列表來替換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);
}
);
}
}
);
這是播放列表的結構
export class Playlists {
headerPlaylists: Array<Playlist>;
bodyPlaylists: Array<Playlist>;
wholePlaylists: Array<Playlist>;
}
----------------更新----------------------如答案中所述,我進行了以下更改。
@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);
}
}
控制台顯示“我在這里”
我寫在pages.component.ts中
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,我沒有看到“新播放列表即將到來”消息,我使用錯了嗎?
新更新:我檢查了this.playlists,它的觀察者為0,為什么?
不要創建一個PlaylistService來公開PagesComponent可以訂閱的可觀察對象。
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);
}
}
然后將此服務導入您的pagescomponent並訂閱播放列表,如下所示:-
this.playlistService.currentPlaylists().subscribe((playlists) => {
this.playlists = playlists;
},error => {
console.log(error);
});`
請記住,您還必須將此服務導入您的assignPlaylistModal,並按以下方式使用它:-
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);
}
);
}
}
);
不要在此處閱讀有關可觀察對象的更多信息,以了解為什么要使用BehaviourSubject。 http://reactivex.io/documentation/observable.html
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