似乎无法将服务作为提供者添加到 app.component.ts

Question

我需要添加提供商以与app.component.ts共享变量，因为我在应用程序中实时寻找已记录的用户数据，但是我无法似乎要将提供商添加到构造函数，我不断收到以下错误。

firebase：未创建firebase应用程序'[默认]' - 致电firebase app.initializeapp((

这是我的代码的快照：

app.component.ts：

import { UsersServiceProvider } from '../providers/users-service/users-service';
@Component({
  templateUrl: 'app.html',
})
export class MyApp {
    @ViewChild(Nav) navCtrl: Nav;
    rootPage:any = InicioPage;
    constructor(public userServices : UsersServiceProvider) //another imports too
    platform.ready().then(() => {
      statusBar.styleDefault();
      splashScreen.hide();
    });
    var config = {
         //some config for app and firebase
    };
    firebase.initializeApp(config);
    var that = this;
    firebase.auth().onAuthStateChanged((user) => {
        if (user) {
        // Need to set variable on userServices HERE
        }
    })
};

用户服务

import { Injectable } from '@angular/core';
import {AlertController , Platform} from 'ionic-angular'
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
import * as firebase from 'firebase';
@Injectable()
export class UsersServiceProvider {
public currentUser : any;
 constructor(private platform: Platform, public alertCtrl: AlertController, public http: Http) {
}
setCurrentUser(user){
  this.currentUser = user; // WANT TO SET IT HERE
}
}

app.module.ts

Answer 1

这是您从 MyApp：

调用UsersServiceProvider的setCurrentUser()方法的方式

this.userServices.setCurrentUser(user);

在这里，它在上下文

import {
  UsersServiceProvider
} from '../providers/users-service/users-service';
@Component({
  templateUrl: 'app.html',
})
export class MyApp {
  @ViewChild(Nav) navCtrl: Nav;
  rootPage: any = InicioPage;
  constructor(public userServices: UsersServiceProvider) //another imports too
  platform.ready().then(() => {
    statusBar.styleDefault();
    splashScreen.hide();
  });
  var config = { //some config for app and firebase
  };
  firebase.initializeApp(config);
  var that = this;
  firebase.auth().onAuthStateChanged((user) => {
    if (user) {
      this.userServices.setCurrentUser(user); // Need to set variable on userServices HERE
    }
  })
};

Answer 2

我不熟悉firebase，但是您是否尝试在app.module.ts中添加服务？您必须这样做，然后才能将其注入任何班级。它应该喜欢这样：

@NgModule({
declarations: [],
imports: [],
providers: [UsersServiceProvider]
})