我最近几天一直在尝试从AngularJS迁移到Angular。我已经有一个Web应用程序,希望通过重写它来进行练习。旧版本中的一个功能是在HTTP请求期间显示加载动画。我在Google和在线教程上搜索了如何在Angular中实现该功能,并选择了使用服务的方式。下面是代码:
spinner.service.ts
问题在于旋转器一直可见,而不仅仅是在加载过程中。我不知道我做错了什么。有什么想法吗?
spinner.service.ts
import { Injectable } from '@angular/core';
import { Observable, Subject } from 'rxjs/Rx';
export interface ISpinnerState {
show: boolean
}
@Injectable()
export class SpinnerService {
private _spinnerSubject = new Subject();
spinnerState = <Observable<ISpinnerState>>this._spinnerSubject;
show() {
this._spinnerSubject.next(<ISpinnerState>{ show: true });
}
hide() {
this._spinnerSubject.next(<ISpinnerState>{ show: false });
}
}
spinner.component.ts
import {Component, OnDestroy, OnInit} from '@angular/core';
import { Subscription } from 'rxjs/Rx';
import { ISpinnerState, SpinnerService } from './spinner.service';
@Component({
selector: 'loading-spinner',
template: `
<div
class="spinner">
</div>
`,
styles: [`.spinner {position: absolute;left: 46%;top: 12%;background-color:black;width:50px;height:50px}`]
})
export class SpinnerComponent implements OnDestroy, OnInit {
visible = false;
private _spinnerStateChanged: Subscription;
constructor(private _spinnerService: SpinnerService) { }
ngOnInit() {
this._spinnerStateChanged = this._spinnerService.spinnerState
.subscribe((state: ISpinnerState) => this.visible = state.show);
}
ngOnDestroy() {
this._spinnerStateChanged.unsubscribe();
}
}
目前,它只是一个黑色的正方形,以便我可以测试它。之后,我将添加适当的加载图标。这是另一个服务,在HTTP请求期间调用它。
apartment.service.ts
....other stuff
@Injectable()
export class ApartmentService {
constructor(
private _http: Http,
private _spinnerService: SpinnerService
) { }
getApartments() {
this._spinnerService.show();
return this._http.get(API + 'apartments')
.map((response: Response) => <Apartment[]>response.json().apartments)
//.catch(this._exceptionService.catchBadResponse)
.finally(() => this._spinnerService.hide());
}
}
问题在于旋转器一直可见,而不仅仅是在加载过程中。我不知道我做错了什么。有什么想法吗?
spinnerState = <Observable<ISpinnerState>>this._spinnerSubject;
应该改成spinnerState = <Observable<ISpinnerState>>this._spinnerSubject.asObservable();
。 - Günter Zöchbauervisible
来显示/隐藏旋转器? - Günter Zöchbauer[ts] Property 'asObservable' does not exist on type 'Subject<{}>'.
你说的“我提供服务的地方”是什么意思? - Tasos