如何在 Angular 6 中观察服务变量 [英] How to watch service variable in Angular 6

问题描述

我几天来一直试图让 Angular 更新服务变量open_popup"，但没有成功.

TLDR;我想要做的是，每当变量open_popup"发生变化时，让它在组件上也发生变化，也能够从组件函数中更改服务变量.

这是我迄今为止尝试过的.

<块引用>

app/src/app/audience-creator/shared/audience-creator.service.ts

import { Injectable } from "@angular/core";从rxjs/index"导入{Observable}；从rxjs/index"导入 { of };@Injectable()导出类 AudienceCreatorService {构造函数(私有 http:HttpClient){}public open_popup = false;公共切换创建者弹出(){this.open_popup = !this.open_popup;}popupIsOpen(): Observable{返回(this.open_popup)；}}

<块引用>

app/src/app/audience-creator/audience-creator.component.ts

import {Stuff} from "@angular/core";@成分({选择器:'观众创造者'，templateUrl: 'audience-creator.html'})导出类 AudienceCreatorComponent 实现 AfterViewInit、OnInit {public popup_is_open = false;@输入()观众创作者服务；ngOnInit() {this.audience_creator_service.popupIsOpen().subscribe(popup_is_open =>this.popup_is_open = popup_is_open);}}

<块引用>

app/src/app/audience-creator/audience-creator.html

-->{{ this.popup_is_open }} 变量总是假的.

不起作用

{{ this.popup_is_open }}

PS:只是试图将函数直接破解到模板中并且它可以工作，所以我绑定组件变量的方式一定有问题??

{{ Audience_creator_service.popupIsOpen().value }}

解决方案

@Injectable()导出类 AudienceCreatorService {构造函数(私有 http:HttpClient){}公共 open_popup = false私有 isOpen: BehaviorSubject= 新行为主题(假)；公共切换创建者弹出(){this.open_popup = !this.open_popup;this.isOpen.next(this.open_popup);}popupIsOpen(): Observable{返回 this.isOpen.asObservable();}}

ive been trying to make Angular update the service variable "open_popup" for days with no luck.

TLDR; What I'm trying to do, is whenever the variable "open_popup" changes, make it change on the component too also be able to change the service variable from a component function.

This is what I've tried so far.

app/src/app/audience-creator/shared/audience-creator.service.ts

import { Injectable } from "@angular/core";
import {Observable} from "rxjs/index";
import { of } from "rxjs/index";

@Injectable()
export class AudienceCreatorService {
    constructor(private http: HttpClient) {}

    public open_popup = false;

    public toggleCreatorPopup() {
        this.open_popup = !this.open_popup;
    }

    popupIsOpen(): Observable<any> {
        return of(this.open_popup);
    }
}

app/src/app/audience-creator/audience-creator.component.ts

import {Stuff} from "@angular/core";

@Component({
    selector: 'audience-creator',
    templateUrl: 'audience-creator.html'
})
export class AudienceCreatorComponent implements AfterViewInit, OnInit {

    public popup_is_open = false;

    @Input()
    audience_creator_service;

    ngOnInit() {
        this.audience_creator_service.popupIsOpen().subscribe(
            popup_is_open => this.popup_is_open = popup_is_open
        );
    }
}

app/src/app/audience-creator/audience-creator.html

--> {{ this.popup_is_open }} variable is always false.

doesn't work

{{ this.popup_is_open }}

PS: just tried to hack the function directly into the template and it works so there must be something wrong with the way im binding the component variable??

{{ audience_creator_service.popupIsOpen().value }}

解决方案

@Injectable()
export class AudienceCreatorService {
constructor(private http: HttpClient) {}

public open_popup = false
private isOpen: BehaviorSubject<boolean> = new BehaviorSubject(false);

public toggleCreatorPopup() {
    this.open_popup = !this.open_popup;
    this.isOpen.next(this.open_popup);
}

popupIsOpen(): Observable<any> {
    return this.isOpen.asObservable();
}
}

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