get data from local Json file ionic 3

Question

I start a dummy project in Ionic. I try to get data from a local Json file but I have this error :

I don't understand why there is no provider for HttpClient. For further details, I actually tried to follow this tutorial : https://www.youtube.com/watch?v=vuc4dp0qHSc

How can I fix this error and get the data ?

Versions

Ionic 3.18.0

Angular 5.0.1

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { ErrorHandler, NgModule } from '@angular/core';
import { IonicApp, IonicErrorHandler, IonicModule } from 'ionic-angular';
import { SplashScreen } from '@ionic-native/splash-screen';
import { StatusBar } from '@ionic-native/status-bar';

import { MyApp } from './app.component';
import { HomePage } from '../pages/home/home';
import { FirstPage } from '../pages/first/first';
import { CardsDataProvider } from '../providers/cards-data/cards-data';

@NgModule({
  declarations: [
    MyApp,
    HomePage,
    FirstPage
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage,
    FirstPage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    {provide: ErrorHandler, useClass: IonicErrorHandler},
    CardsDataProvider,

  ]
})
export class AppModule {}

cards-data.ts

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import 'rxjs/add/operator/map';

/*
  Generated class for the CardsDataProvider provider.

  See https://angular.io/guide/dependency-injection for more info on providers
  and Angular DI.
*/
@Injectable()
export class CardsDataProvider {

  constructor(public http: HttpClient) {
    console.log('Hello CardsDataProvider Provider');
  }

  getLocalData() {
  this.http.get('../assets/data/cards.json').map(res => res.json()).subscribe(data => 
  {
    console.log(data);
  });  
}
}

home.ts

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { FirstPage } from '../first/first';
import { CardsDataProvider } from '../../providers/cards-data/cards-data';


@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  constructor(public navCtrl: NavController, public CardsService: CardsDataProvider) {

  }
  openFirstPage() {
    this.navCtrl.push(FirstPage);
  }

  ionViewDidLoad() {
    this.CardsService.getLocalData();
  }
} 

Any help will be appreciated.

Answer 1

You are following an Ionic2 tutorial while using Ionic3 with Angular5.

For Http to work since Ionic 3.0, you need to include HttpClientModule in your imports in app.module.ts.

import {HttpClientModule} from '@angular/common/http';//import

@NgModule({
  declarations: [
    MyApp,
    HomePage,
    FirstPage
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    HttpClientModule//include here
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage,
    FirstPage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    {provide: ErrorHandler, useClass: IonicErrorHandler},
    CardsDataProvider,

  ]
})
export class AppModule {}

Also, in your cards-data.ts,

import {Http} from '@angular/common/http';

@Injectable()
export class CardsDataProvider {

  constructor(public http: HttpClient) { //change here
    console.log('Hello CardsDataProvider Provider');
  }

For further changes to go from Ionic 2 to 3 check here. For changes required to go to Angular 5 check here.

A simpler way is to find a more recent tutorial.