Question

在名为bd的服务中，我有一个名为ConsultaPublicacoes的方法，该方法返回我在Firebase数据库上拥有的，用于特定用户电子邮件的所有发布。

bd.service

public consultaPublicacoes(email:string):Observable<any>{

       return this.checkarPublicacoes=new Observable((observer)=>{
           firebase.database().ref(`publicacoes/${btoa(email)}`)
           .orderByKey()
           .once('value')
           .then((snapshot:any)=>{

               let publicacoes:Array<Publicacao>=[] 


               snapshot.forEach((childSnapshot:any) => {
                    let publicacao=childSnapshot.val()
                    publicacao.key=childSnapshot.key
                    publicacoes.push(publicacao)

               });
              return publicacoes.reverse()
           }).then((publicacoes:any)=>{

                publicacoes.forEach((publicacao)=>{
                    firebase.storage().ref().child(`imagens/${publicacao.key}`).getDownloadURL()
                    .then((url:string)=>{
                        publicacao.url_imagem=url

                        firebase.database().ref(`usuario_detalhe/${btoa(email)}`).once('value')
                        .then((snapshot:any)=>{
                            publicacao.nome_usuario=snapshot.val().nome_usuario
                            })

                      })

                 })
                    observer.next(publicacoes)


            })


       })

我在publicacoesComponent上还有一个名为atualizarTimeLine（）的方法，该方法负责将从Observable返回的数据关联到名为this.publicacoes（PublicacoesComponent）的变量中。

PublicacoesComponent

export class PublicacoesComponent implements OnInit, OnDestroy {
  public email:string
  public publicacoes:Publicacao[];
  public gostou:boolean=false;

  constructor(private bd:Bd) { }

  ngOnInit() {

    firebase.auth().onAuthStateChanged((user)=>{
      if(user!=null){
      this.email=user.email
      this.atualizarTimeLine()
      }
    })
    this.atualizarTimeLine();

  }

  public atualizarTimeLine(){
    console.log("atualizarTimeLine from publicacoes")
    this.bd.consultaPublicacoes(this.email)
    .subscribe((publicacoes:any)=>{

      console.log(publicacoes)
      this.publicacoes=publicacoes

    })

  }
....

MenuComponent

export class MenuComponent implements OnInit {

  email: string;


  constructor(private bd:Bd, private router:Router, private autenticacao:Autenticacao) { }

  ngOnInit() {
    firebase.auth().onAuthStateChanged((user)=>{
      if(user!=null){
      this.email=user.email
      this.atualizarTimeLine()
      }
    })
    this.atualizarTimeLine()
  }


  atualizarTimeLine(){
    console.log("atualizarTimeLine From MenuComponent")
    this.bd.consultaPublicacoes(this.email)
    //this.router.navigate(['/home']);
  }

我希望每次从MenuComponent（this.bd.consultaPublicacoes（））调用ConsultaPublicacoes时都能够更新（publicacoesComponent的）变量publicacoes的值，该怎么办？在ConsultaPublicacao中观察到的最佳选择吗？

Answer 1

只需使用.db.service这样的'Subject'：firebaseSubject = new Subject（）。在ConsultaPublicacoes函数中：firebaseSubject.next（publicacoes）。 publicacoesComponent：firebaseSubject.subscribe（（publicacoes）=> {}）。 MenuComponent：this.atualizarTimeLine（）;

用一个可观察的

1 个答案: