Check network status using network native not working

I am working on ionic 4 project. My project is getting data json from url . l am try to use Network native for ionic to check internet connections for my app .But l got nothing to show. No data and no alert to show .

 constructor(private http: HTTP, public loadingController: LoadingController,private network: Network,
   public alertController : AlertController, public platform : Platform) {


    // watch network for a disconnection
    let disconnectSubscription = this.network.onDisconnect().subscribe(() => {

      this.AlertNet()

    });



    // watch network for a connection
    let connectSubscription = this.network.onConnect().subscribe(() => {
      console.log('network connected!');


      this.getData()

      setTimeout(() => {
        if (this.network.type === 'wifi') {
          console.log('we got a wifi connection, woohoo!');
        }
      }, 3000);
    });




       }

      async getData() {


          const loading = await this.loadingController.create({
            message: 'Loading'
          });
          await loading.present();
          this.http.get('/v1/airport.json?code=krt', {}, {})
          .then(data => {

            this.test = JSON.parse(data.data);
            const parsed = JSON.parse(data.data);


          }), err=>{
            this.test =err
            loading.dismiss()
          }



      }


     async AlertNet(){

      const alert = await this.alertController.create({
        header: 'Alert',
        subHeader: 'No internet',
        message: 'You do not have an Internet connection. Please check your connection status',
        buttons: [{
          text: "Ok",
          handler: () => { this.platform.backButton.subscribe(()=>{
            navigator['app'].exitApp();
        });
       }
        }]    
        });

      await alert.present();

     }