Angular 5 BehaviorSubject 不适用于布尔值

Question

我正在尝试练习 angular 中的 behaviorsubject 5. 我正在编写一个包含两个组件的小应用程序，我想同时更改两个组件中的值，但该值没有改变。 BehaviorSubject 应该更改所有组件中的值。请帮助我理解。

服务

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


@Injectable()
export class TestserviceService {

public isAdmin = new BehaviorSubject<boolean>(false);
cast = this.isAdmin.asObservable();

constructor() { }

changeAdmin(){
  this.isAdmin.next(!this.isAdmin);
}

}

组件一

import { Component, OnInit } from '@angular/core';
import{ TestserviceService } from '../../testservice.service'; 

@Component({
  selector: 'app-one',
  templateUrl: './one.component.html',
  styleUrls: ['./one.component.css']

})
   export class OneComponent implements OnInit {
  isAdmin: boolean;
  constructor(private testservice: TestserviceService) { }


  ngOnInit() {
    this.testservice.cast.subscribe(data => this.isAdmin = data);

  }

  changeValue(){
    this.testservice.changeAdmin();
    console.log(this.isAdmin);
  }

}

组件一 html

<button (click)="changeValue()">Click Me</button>
<p>
  one {{isAdmin}}
</p>

第二部分

import { Component, OnInit } from '@angular/core';
import { TestserviceService } from '../../testservice.service';

@Component({
  selector: 'app-two',
  templateUrl: './two.component.html',
  styleUrls: ['./two.component.css']
})
    export class TwoComponent implements OnInit {
  isAdmin: boolean;
  constructor(private testservice: TestserviceService) { }


  ngOnInit() {
    this.testservice.cast.subscribe(data => this.isAdmin = data);
    console.log("two "+this.isAdmin);
  }


}

Answer 1

将您的服务更改为：

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';
@Injectable()
export class SharedServiceService {

  constructor() { }
  public isAdmin = new BehaviorSubject<boolean>(false);
  cast = this.isAdmin.asObservable();

  changeAdmin(){
    this.isAdmin.next(!this.isAdmin.value);
  }
}

应该是this.isAdmin.value因为this.admin只会是behaviorSubject的对象

Live Demo

Answer 2

changeAdmin(){
  this.isAdmin.next(!this.isAdmin);
}

应该是

changeAdmin(){
  this.isAdmin.next(!this.isAdmin.value);
}

this.isAdmin 是一个 BehaviorSubject 并且您试图设置 !thisAdmin 其计算结果为 false

Stackblitz