5等待多个子通知

这个 forkJoin 函数将只在给定的可观测值 . i、 例如,当你简单地给出可观察物时,它不会发射

因为你正在使用 BehaviorSubject this._loadFinished.next(true) 只会从可观察到的对象中发出一个值,它不会完成。

一个简单的解决方法就是打电话 _loadFinished.complete() 发出唯一值后:

networkLoad() {
   this.network.doLoad().subscribe(x => {
       this._loadFinished.next(true);
       this._loadFinished.complete();
   });
}

如果你有一些理由把行为主体放在身边,你可能也会发现 Observable.combineLatest

您正在访问ngOnInit()中的“@ViewChild('orgMetrics')”组件。但是正确的方法是使用ngAfterViewInit()。另一种方法是,在服务内部声明行为主体Observable和observator,并通过组件进行访问。

服务:

private _loadFinished = new BehaviorSubject<boolean>(null);
loadFinished = this._loadFinished.asObservable();
private _loadFinished1 = new BehaviorSubject<boolean>(null);
loadFinished1 = this._loadFinished1.asObservable();

load1Finished(){ //call this method from child component
  this.loadFinished.next(true);
}

load2Finished(){ //call this method from child component
  this.loadFinished1.next(true);
}

loading = true;

ngOnInit(): void {
    forkJoin(
        this.Service.loadFinished,
        this.Service.loadFinished1
    ).subscribe(() => {
        console.info("I got here");
        this.loading = false;
    }, () => this.loading = false);
}

你可以用 EventEmitter

import { Component } from '@angular/core';
@Component({
  selector: 'app-parent',
  templateUrl: './parent.html'
})
export class ParentComponent {
  onChanges(event){
    console.log(event);
  }
}

<app-child (valueChange)="onChanges($event)"></app-child>

孩子:

import { Component, EventEmitter } from '@angular/core';
@Component({
  selector: 'app-child',
  templateUrl: './child.html'
})
export class ChildComponent {
  @Output() valueChange = new EventEmitter();

  networkFinished() {
    this.valueChange.emit('child1');
  }
}

Here is a working example