将服务提供者置于 angular 2 层次结构的何处，以便组件可以使用相同的服务实例相互通信？

Question

相关问题：

Using observable talk to other component in angular2, not receiving coming value

我有一个具有 setCurrentPlaylists 函数的 PagesService，这个函数将从其他组件触发，它将接收一个播放列表类型的值，并将控制台记录这个值，使用下一个函数传递给其他组件（我意图）。

我的页面服务的全部代码是：

import { Injectable } from '@angular/core';

import { ApiService } from '../../apiService/api.service';
import { Platform } from '../../platforms/shared/platform.model';
import { Page } from './page.model';
import { Playlists } from '../shared/playlists.model';
import { Subject, BehaviorSubject } from 'rxjs/Rx';


@Injectable()
export class PagesService {

  private currentPlaylists: Subject<Playlists> = new  BehaviorSubject<Playlists>(new Playlists());


  constructor(private service: ApiService) {
    this.currentPlaylists.subscribe((v) => console.log(v, 'subscriber from pages service is printing out the incoming value'));
  }

  getPages(platform: Platform) {
    return this.service.getPages(platform.value);
  }

  setCurrentPage(page: Page) {
    this.service.setCurrentPage(page.pageId);
  }

  getCurrentPage():string {
    return this.service.getCurrentPage();
  }

  getCurrentPlaylists() {
    return this.currentPlaylists;
  }

  setCurrentPlaylists(playlists: Playlists) {
    console.log("Pages Service receive an value of playlists:", playlists);
    this.currentPlaylists.next(playlists);
  }
}

我的页面组件代码是：

import { Component, OnInit, Input, Output, OnChanges, EventEmitter, Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';

import { Platform } from '../platforms/shared/platform.model';
import { Page } from './shared/page.model';
import { Playlists } from './shared/playlists.model';
import { PagesService } from './shared/pages.service';
import { PlaylistService } from '../playlist/shared/playlist.service';
import { Subject,BehaviorSubject } from 'rxjs/Rx';


@Component({
  selector: 'pages',
  styleUrls: ['app/pages/pages.css'],
  templateUrl: 'app/pages/pages.html',
  providers: [PagesService, PlaylistService]
})

export class PagesComponent {

  @Input() platform: Platform;

  @Output() onPlaylistsChange: EventEmitter<Playlists>;

  currentPageName: string;

  currentPage: Page;

  pages: Array<Page>;

  playlists: Playlists;

  constructor(private pageServer: PagesService, private playlistService: PlaylistService) {
    this.pages = [];
    this.currentPage = new Page();
    this.pageServer.setCurrentPage(this.currentPage);
    this.playlists = new Playlists();
    this.onPlaylistsChange = new EventEmitter<Playlists>();
  }

  ngOnInit() {
    this.pageServer.getCurrentPlaylists().subscribe((playlists) => {
      console.log('subscriber in pages component is printing out the incoming value', playlists);
      this.playlists = playlists;
    }, error => {
      console.log(error);
    });
  }

  getPages(platform: Platform): void {
    this.pageServer.getPages(platform)
      .subscribe(
      res => {
        if (res.pages.length > 0) {
          this.pages = [];
          for (let page of res.pages) {
            if (page.pageName !== "Shows" && page.pageName !== "All Shows" && page.pageName !== "Moives" && page.pageName !== "All Movies") {
              this.pages.push(page);
            }
          }
          this.currentPage = this.pages[0];
          this.pageServer.setCurrentPage(this.currentPage);
          this.currentPageName = this.pages[0].pageName;
          this.getPlaylist(this.currentPage, this.platform);
        } else {
          this.pages = [];
          this.currentPage = new Page();
          this.pageServer.setCurrentPage(this.currentPage);
          this.playlists = new Playlists();
          this.onPlaylistsChange.emit(this.playlists);
        }
      },
      error => console.log(error)
      );
  }

  getPlaylist(page: Page, platform: Platform): void {
    this.currentPage = page;
    this.pageServer.setCurrentPage(this.currentPage);
    this.playlistService.getPlaylist(page, platform)
      .subscribe(
      res => {
        if (res.hasOwnProperty('pages') && res.pages.length > 0) {
          if (res.pages[0].hasOwnProperty('bodyPlaylists') && res.pages[0].hasOwnProperty('headerPlaylists')) {
            this.playlists.bodyPlaylists = res.pages[0].bodyPlaylists || [];
            this.playlists.headerPlaylists = res.pages[0].headerPlaylists || [];
          } else {
            this.playlists.bodyPlaylists = [];
            this.playlists.headerPlaylists = [];
            this.playlists.wholePlaylists = res.pages[0].playlists || [];
          }
          this.onPlaylistsChange.emit(this.playlists);
        } else {
          this.playlists = new Playlists();
          this.onPlaylistsChange.emit(this.playlists);
        }
      },
      error => console.error(error)
      );
  }

  ngOnChanges() {
    // Get all Pages when the platform is set actual value;
    if (this.platform.hasOwnProperty('value')) {
      this.getPages(this.platform);
    }
  }

}

当我触发 setCurrentPlaylists 函数时，播放列表没有传递到页面组件。我需要使用传递的值来更新页面组件的播放列表。

这是我触发setCurrentPlaylsts函数后的控制台输出。没有来自页面组件的消息。

如有任何建议，我们将不胜感激！

我从该组件调用 setCurrentPlaylists 函数

/// <reference path="../../../typings/moment/moment.d.ts" />
import moment from 'moment';

import { Component, ViewChild, ElementRef, Input, Output, EventEmitter } from '@angular/core';
import { CORE_DIRECTIVES } from '@angular/common';
import { Http, Response } from '@angular/http';
import { MODAL_DIRECTVES, BS_VIEW_PROVIDERS } from 'ng2-bootstrap/ng2-bootstrap';
import {
  FORM_DIRECTIVES,
  REACTIVE_FORM_DIRECTIVES,
  FormBuilder,
  FormGroup,
  FormControl,
  Validators
} from '@angular/forms';

import { PagesService } from '../../pages/shared/pages.service';
import { ApiService } from '../../apiService/api.service';

@Component({
  selector: 'assign-playlist-modal',
  providers: [PagesService],
  exportAs: 'assignModal',
  directives: [MODAL_DIRECTVES, CORE_DIRECTIVES, FORM_DIRECTIVES, REACTIVE_FORM_DIRECTIVES ],
  viewProviders: [BS_VIEW_PROVIDERS],
  styleUrls: ['app/channel/shared/assignPlaylist.css'],
  templateUrl: 'app/channel/modals/assignPlaylistModal.html'
})

export class AssignPlaylistModalComponent {

  @ViewChild('assignPlaylistModal') modal: any;

  private addPlaylistForm: FormGroup;

  private playlistType: string;

  private currentPage: string;

  private editDate: string;

  constructor(private apiService: ApiService, private pagesService: PagesService, fb: FormBuilder) {
    this.currentPage = '';
    this.editDate = this.apiService.getDate();
    this.addPlaylistForm = fb.group({
      'longPlaylistName': ['', Validators.required],
      'shortPlaylistName': ['', Validators.required],
      'startOn': ['', Validators.compose([
        Validators.required, this.validTimeFormat
      ])],
      'expireOn': ['', Validators.compose([
        Validators.required, this.validTimeFormat
      ])],
      'isExpire': ['']
    });

    this.addPlaylistForm.controls['startOn'].valueChanges.subscribe((value: string) => {
      if (moment(value, 'YYYY-MM-DDThh:mm').isValid()) {
        if (this.playlistType == 'dynamic') {
          this.apiService.setGlobalStartTime(moment(value).format("YYYYMMDDHHmm"));
        }
      }
    });

    this.addPlaylistForm.controls['expireOn'].valueChanges.subscribe((value: string) => {
      if (moment(value, 'YYYY-MM-DDThh:mm').isValid()) {
        if (this.playlistType == 'dynamic') {
          this.apiService.setGlobalEndTime(moment(value).format("YYYYMMDDHHmm"));
        }
      }
    });
  }

  showModal(type: string) {
    this.playlistType = type;
    this.currentPage = this.apiService.getCurrentPage();
    this.modal.show();
  }

  validTimeFormat(control: FormControl): { [s: string]: boolean} {
    if (!moment(control.value, 'YYYY-MM-DDThh:mm').isValid()) {
      return { invalidTime: true};
    }
  }

  setCloseStyle() {
    let styles = {
      'color': 'white',
      'opacity': 1
    }
    return styles;
  }

  createNewPlaylist(stDate: string, etDate: string, playlistTitle: string, shortTitle: string, callback?: any):any {
    this.apiService.createNewPlaylist(stDate, etDate, playlistTitle, shortTitle)
    .subscribe(
      data => {
          let playlistId = data[0].id;
          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 => {
                    if (res.hasOwnProperty('pages') && res.pages.length > 0) {
                      if (res.pages[0].hasOwnProperty('bodyPlaylists') && res.pages[0].hasOwnProperty('headerPlaylists')) {
                        this.apiService.getCurrentPlaylists().bodyPlaylists = res.pages[0].bodyPlaylists || [];
                        this.apiService.getCurrentPlaylists().headerPlaylists = res.pages[0].headerPlaylists || [];
                        console.log('assign playlist component is calling the pages service setCurrentPlaylists function.');
                        this.pagesService.setCurrentPlaylists(this.apiService.getCurrentPlaylists());
                      } else {
                        this.apiService.getCurrentPlaylists().bodyPlaylists = [];
                        this.apiService.getCurrentPlaylists().headerPlaylists = [];
                        this.apiService.getCurrentPlaylists().wholePlaylists = res.pages[0].playlists || [];
                        console.log('assign playlist component is calling the pages service setCurrentPlaylists function.');
                        this.pagesService.setCurrentPlaylists(this.apiService.getCurrentPlaylists());
                      }
                    }
                  }
                );
            } else {
              this.apiService.getPlaylist(this.apiService.getCurrentPage(), 'false' )
              .subscribe(
                res => {
                  if (res.hasOwnProperty('pages') && res.pages.length > 0) {
                      this.apiService.getCurrentPlaylists().bodyPlaylists = [];
                      this.apiService.getCurrentPlaylists().headerPlaylists = [];
                      this.apiService.getCurrentPlaylists().wholePlaylists = res.pages[0].playlists || [];
                      console.log('assign playlist component is calling the pages service setCurrentPlaylists function.');
                      this.pagesService.setCurrentPlaylists(this.apiService.getCurrentPlaylists());
                  }
                }
              );
            }
            }
          );
      },
      error => console.log(error)
    );

  }

  onSubmit(form: FormGroup) {


    // get start time, the format from input will be like 2016-06-07T00:05
    let startTime = moment(form.value.startOn).format("YYYYMMDDHHmm");
    let expireTime = moment(form.value.expireOn).format("YYYYMMDDHHmm");
    let playlistTitle = form.value.longPlaylistName;
    let shortTitle = form.value.shortPlaylistName;
    if (this.playlistType == 'smart' || this.playlistType == 'new') {
      this.createNewPlaylist(startTime, expireTime, playlistTitle, shortTitle);
    }
  }

}

这是我的组件树：

Answer 1

从你提供的代码来看，我看不出这个方法是什么时候

  setCurrentPlaylists(playlists: Playlists) {
    console.log(playlists, 'i am here');
    this.currentPlaylists.next(playlists);
  }

被调用。因此，您的列表是空的。

这样做

this.pageServer.getCurrentPlaylists().subscribe((playlists) => {
      console.log(playlists, 'new playlists coming');
      this.playlists = playlists;
    }, error => {
      console.log(error);
    });

仅创建对可观察对象的订阅。您需要从某个地方发布数据。

另外，这段代码最好搬走

this.pageServer.getCurrentPlaylists().subscribe((playlists) => {
      console.log(playlists, 'new playlists coming');
      this.playlists = playlists;
    }, error => {
      console.log(error);
    });

到ngOnInit()

Answer 2

我假设你的组件树如下：

AssignPlaylistModalComponent (Parent or higher level than PagesComponent in the tree)
  PagesComponent (lowest level child as it does not import any directive)

问题

您应该只将您的服务放在顶级（父）组件中 provider。尽管所有组件仍然需要进行导入和构造。

将服务放在组件的提供程序中将创建服务的新副本并沿着组件树向下而不是向上共享。

在相关代码中，PagesComponent 作为树中最低级别的子项，具有自己的 provider 行，实际上正在启动自己的 PagesService 副本 PlaylistService。所以 PagesComponent 的每个实例基本上只听自己的。它不会收到来自其他人的任何消息。

修复

@Component({
  selector: 'pages',
  styleUrls: ['app/pages/pages.css'],
  templateUrl: 'app/pages/pages.html',
  providers: [PagesService, PlaylistService] // <--- Delete this line
})

export class PagesComponent {

  @Input() platform: Platform;

  @Output() onPlaylistsChange: EventEmitter<Playlists>;

放在哪里`providers`

假设以下组件树：

   Component A1 (root component)
     Component B1
       Component C1
       Component C2
     Component B2
       Component C3
       Component C4

最简单的方法是将其放在 A1 中 providers，所有组件将共享同一个服务实例，并且能够相互发送消息。

如果放在B1providers，那么只有B1，C1，C2可以互相通话。

根据最新更新，项目的根组件是AppComponent.ts。 providers应该加进去

将服务提供者置于 angular 2 层次结构的何处，以便组件可以使用相同的服务实例相互通信？

Where to put service providers in angular 2 hierarchy so that components can talk to each other using the same instance of service?

javascript

angular

reactive-programming

rxjs

angular2-injection

问题

修复

放在哪里`providers`

将服务提供者置于 angular 2 层次结构的何处，以便组件可以使用相同的服务实例相互通信？

Where to put service providers in angular 2 hierarchy so that components can talk to each other using the same instance of service?

javascript

angular

reactive-programming

rxjs

angular2-injection

问题

修复

放在哪里providers

放在哪里`providers`