angular2 http攔截器並注入SlimLoadingBarService不起作用？

Question

我寫了一個http intercpetor，它是這樣的：

import { Injectable, Inject } from '@angular/core';
import { SlimLoadingBarService } from 'ng2-slim-loading-bar';
// ... other imports in here

@Injectable()
export class HttpInterceptorService extends Http {
    private apiEndpoint: string;

    constructor(
        @Inject(CONFIG_TOKEN) config: Config,
        private backend: ConnectionBackend,
        private defaultOptions: RequestOptions,
        private slimLoadingBarService: SlimLoadingBarService
    ) {
        super(backend, defaultOptions);
        this.apiEndpoint = config.apiEndpoint;
    }

    get(url: string, options?: RequestOptionsArgs): Observable<any> {
        this.beforeRequest();
        return super.get(this.getFullUrl(url), this.requestOptions(options))
            // ...
    }

    private beforeRequest(): void {
        // this is not work
        this.slimLoadingBarService.start();
    }

    // ... other methods
}

我的app.module提供這樣的配置：

{
    provide: HttpInterceptorService,
    useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => {
        return new HttpInterceptorService(CONFIG, backend, 
            defaultOptions, new SlimLoadingBarService);
    },
    deps: [XHRBackend, RequestOptions]
}

現在，這個Http攔截器是worker，但是SlimLoadingBarService卻無法正常工作。

我覺得傳遞new SlimLoadingBarService引線應該是錯誤的，但是直接傳遞SlimLoadingBarService ，將給出相同的結果，現在卡在這個地方不知道如何繼續。

沒有錯誤消息，但是loadingbar（ SlimLoadingBarService ）沒有顯示。

Answer 1

試試這個吧。

{
  provide: HttpInterceptorService,
  useFactory: (backend: XHRBackend, defaultOptions: RequestOptions, slimLoadingBarService: SlimLoadingBarService) => {
    return new HttpInterceptorService(CONFIG, backend, 
        defaultOptions, slimLoadingBarService);
  },
  deps: [XHRBackend, RequestOptions, SlimLoadingBarService]
}