Question

我有两个由延迟加载加载的独立模块，我试图在它们之间传递一些数据，而这由服务执行，服务应该是单例吧？但是当我注入服务时，为什么会实例化？

这是第一个组件的代码

import { Component} from '@angular/core';
import { LocationService } from '../services/location.service';
import {Location} from '../shared/location';
import { NgForm } from '@angular/forms';
@Component({
  selector: 'app-about',
  templateUrl: 'about.page.html',
  styleUrls: ['about.page.scss']
})
export class AboutPage {
  country :string;
  city :string;
  constructor(public locationService: LocationService){ }


  locationSelected(){

    let newLocation =  {country: this.country,city: this.city};
    this.locationService.location = newLocation;
    console.log(this.locationService.location);
  }
}

这是第二个组成部分

import { Component, OnInit, Input } from '@angular/core';
import {LocationService} from '../Services/location.service';
import { PrayerTimeService } from '../services/prayer-time.service';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss']
})

export class HomePage implements OnInit {
  @Input()
  prayerTime = {
    Asr : "15:48 (AST)",
    Dhuhr : "12:29 (AST)",
    Fajr : "04:36 (AST)",
    Isha : "20:23 (AST)",
    Maghrib : "19:02 (AST)",
    Sunrise : "05:56 (AST)"
  }
  constructor(private prayerTimeService: PrayerTimeService, public locationService : LocationService){}

  ngOnInit(){
    console.log(this.locationService.location);
    this.getPrayerTimes();
  }


  getPrayerTimes(){
    this.prayerTimeService.getTimes(this.locationService.location.country, this.locationService.location.city).subscribe((data) => {
      this.prayerTime = data.data[0].timings;
      console.log(this.prayerTime);
    });
  }
}

以及提供服务的父模块

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { RouterModule, RouteReuseStrategy } from '@angular/router';
import { HttpClientModule } from '@angular/common/http';
import { IonicModule, IonicRouteStrategy } from '@ionic/angular';
import { SplashScreen } from '@ionic-native/splash-screen/ngx';
import { StatusBar } from '@ionic-native/status-bar/ngx';
import { LocationService } from './Services/location.service';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import {FormsModule} from '@angular/forms';
import {AboutPageModule} from './about/about.module';

@NgModule({
  declarations: [AppComponent],
  entryComponents: [],
  imports: [BrowserModule, IonicModule.forRoot(), AppRoutingModule, HttpClientModule, FormsModule, AboutPageModule],
  providers: [
    StatusBar,
    SplashScreen,
    LocationService,
    { provide: RouteReuseStrategy, useClass: IonicRouteStrategy }
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

这是服务

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Location } from '../Shared/location';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class LocationService {
  location : Location = new Location("","");
  constructor(private http : HttpClient) { console.log("new Service has Been created");}



}

Answer 1

该服务没有恢复原状。问题在于在ngOnInit中对服务的调用发生在调用locationSelected（）方法之前。因此，此位置不会在此后不久初始化。

重新实例化Angular 5服务

1 个答案: