How to check a web api call when the data connectivity is off or no active data?

I am new in interceptor concept of ionic 3. As a requirement i need to check the net connectivity before calling a web service. I call web services through ‘providers’. I created a request interceptor with code


import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpHandler, HttpRequest, HttpEvent, HttpResponse } from '@angular/common/http';
import { AlertController, Platform } from 'ionic-angular';
import { Observable } from 'rxjs/Observable';
import { Network } from 'ionic-native';
import 'rxjs/add/operator/do';

export class RequestInterceptor implements HttpInterceptor {
  constructor(private alertCtrl: AlertController, public platform: Platform, private network: Network ) {}
    req: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {

    return next.handle(req).do(evt => {
      if (evt instanceof HttpResponse) {
        console.log('---> status:', evt.status);
        console.log('---> filter:', req.params.get('filter'));
        this.platform.ready().then(() => {
          var networkState = Network.type;
          let alert = this.alertCtrl.create({
          title: "Connection Status",
          subTitle: networkState,
          buttons: ["OK"]


and included in app.module.ts.

But it work fine when data connectivity is fine (Show alert message), but when data is off it will not show the status of the connection. Please help how to take the status of offline and/or No Data situation.

My another doubt is in ionic 3 we can navigate the user to network settings ?

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