Ionic 2: Facebook Login -> Error: No Provider in NavController (TypeScript) - facebook

Question

I've been working on the facebook login for my ionic 2 app
(used this tutorial: https://ionicthemes.com/tutorials/about/ionic2-facebook-login)
But now i get a weird error:
RunTimeError Error in :0:0 caused by: No provider for NavController
app.component.ts:
import { Component } from '#angular/core';
import { Platform } from 'ionic-angular';
import { StatusBar } from '#ionic-native/status-bar';
import { SplashScreen } from '#ionic-native/splash-screen';
import { NativeStorage } from '#ionic-native/native-storage';
import { TabsPage } from '../pages/tabs/tabs';
import { WelcomePage } from '../pages/welcome/welcome';
import { DetailPage } from '../pages/detail/detail';
#Component({
templateUrl: 'app.html'
})
export class MyApp {
rootPage: any = WelcomePage;
constructor(NativeStorage: NativeStorage, platform: Platform, statusBar: StatusBar, splashScreen: SplashScreen) {
platform.ready().then(() => {
// Here we will check if the user is already logged in
// because we don't want to ask users to log in each time they open the app
let env = this;
NativeStorage.getItem('user')
.then((data) => {
// user is previously logged and we have his data
// we will let him access the app
this.rootPage = DetailPage;
splashScreen.hide();
}, (error) => {
//we don't have the user data so we will ask him to log in
this.rootPage = WelcomePage;
splashScreen.hide();
});
statusBar.styleDefault();
});
}
}
welcome.ts:
import { Component } from '#angular/core';
import { Facebook, NativeStorage } from 'ionic-native';
import { NavController } from 'ionic-angular';
import { DetailPage } from '../detail/detail';
import { ViewChild } from '#angular/core';
#Component({
selector: 'page-welcome',
templateUrl: 'welcome.html'
})
export class WelcomePage {
rootPage: any = WelcomePage;
#ViewChild('navRoot') navCtrl: NavController;
FB_APP_ID: number = 123456789;
constructor() {
Facebook.browserInit(this.FB_APP_ID, "v2.8");
}
doFbLogin() {
let permissions = new Array();
let nav = this.navCtrl;
//the permissions your facebook app needs from the user
permissions = ["public_profile"];
Facebook.login(permissions)
.then(function (response) {
let userId = response.authResponse.userID;
let params = new Array();
//Getting name and gender properties
Facebook.api("/me?fields=name,gender", params)
.then(function (user) {
user.picture = "https://graph.facebook.com/" + userId + "/picture?type=large";
//now we have the users info, let's save it in the NativeStorage
NativeStorage.setItem('user',
{
name: user.name,
gender: user.gender,
picture: user.picture
})
.then(function () {
nav.push(DetailPage);
}, function (error) {
console.log(error);
})
})
}, function (error) {
console.log(error);
});
}
}

Answer 1

You cannot import NavController in app.component.ts or the root app page.
OPTION 1:
Try to get it using ViewChild
Give element id to root-nav
<ion-nav #navRoot [root]="rootPage"></ion-nav>
In component:
import {ViewChild} from '#angular/core';
#Component({
templateUrl: 'app.html'
})
export class MyApp {
rootPage: any = WelcomePage;
#ViewChild('navRoot') navCtrl:NavController;
constructor(nativeStorage: NativeStorage, platform: Platform, statusBar: StatusBar, splashScreen: SplashScreen) { //remove navcontroller injected
platform.ready().then(() => {
// Here we will check if the user is already logged in
// because we don't want to ask users to log in each time they open the app
let env = this;
//...
OPTION 2:
From your app.component.ts code, you dont actually need to import NavController at all if your html template only contains,
<ion-nav [root]="rootPage"></ion-nav>
Simply set the required page to rootPage.
nativeStorage.getItem('user')
.then( (data) => {
// user is previously logged and we have his data
// we will let him access the app
this.rootPage = DetailPage;
splashScreen.hide();
}, (error) => {
//we don't have the user data so we will ask him to log in
this.rootPage = WelcomePage;
splashScreen.hide();
});
Side Note: Better to use ()=>{} arrow functions for callbacks instead of saving context in second variable.