Having Trouble with Ionic 2's Loading Controller

Question

Having Trouble with Ionic 2's Loading Controller

In my attempt to utilize the recently added LoadingController in this scenario:

let loading=this.load.create({
  content: "Connexion au serveur Migal en cours..."
});

loading.present();

this.http.get(this.urlCheckerForm.value.migalUrl+'/action/MobileApp/URLChecker')
  .map(res => res.json())
  .subscribe(
    data => this.newConnection(data,loading),
    error => this.catchURLError(loading));

loading.dismiss();

Essentially, I aim to showcase the loading pop-in prior to my page being loaded and dismiss it thereafter.

I attempted following the guide on Ionic 2 Documentation, but unfortunately, it does not seem to be effective...

UPDATE : The loading component fails to appear altogether.

angular typescript ionic-framework ionic2 ionic3

Answer 1

Answer №1

The problem lies in the order of execution in your code. You are sending an http request and then immediately calling the dismiss() method without waiting for the http request to complete. Check out this plunker for reference.

The code provided is quite straightforward:

import { NavController, LoadingController } from 'ionic-angular/index';
import { Http, Response } from '@angular/http';
import { Component } from "@angular/core";
import 'rxjs/Rx';

@Component({
  templateUrl:"home.html"
})
export class HomePage {

  private users : Array<any>

  constructor(private http: Http, private loadingCtrl: LoadingController) {

    // Create the loading popup
    let loadingPopup = this.loadingCtrl.create({
      content: 'Loading data...'
    });

    // Display the loading popup
    loadingPopup.present();

    // Fetch the data
    this.http.get('https://jsonplaceholder.typicode.com/users')
      .map((res: Response) => res.json())
      .subscribe(
        data => {

          // Added a timeout to display the loading popup for a longer duration
          setTimeout(() => {
            this.users= data;
            loadingPopup.dismiss();
          }, 1000);

          // Original code should be like this:
          // this.users= data;
          // loadingPopup.dismiss();
        },
        err => console.error(err)
    );

  }
}

Answer 2

The problem lies in the order of execution in your code. You are sending an http request and then immediately calling the dismiss() method without waiting for the http request to complete. Check out this plunker for reference.

The code provided is quite straightforward:

import { NavController, LoadingController } from 'ionic-angular/index';
import { Http, Response } from '@angular/http';
import { Component } from "@angular/core";
import 'rxjs/Rx';

@Component({
  templateUrl:"home.html"
})
export class HomePage {

  private users : Array<any>

  constructor(private http: Http, private loadingCtrl: LoadingController) {

    // Create the loading popup
    let loadingPopup = this.loadingCtrl.create({
      content: 'Loading data...'
    });

    // Display the loading popup
    loadingPopup.present();

    // Fetch the data
    this.http.get('https://jsonplaceholder.typicode.com/users')
      .map((res: Response) => res.json())
      .subscribe(
        data => {

          // Added a timeout to display the loading popup for a longer duration
          setTimeout(() => {
            this.users= data;
            loadingPopup.dismiss();
          }, 1000);

          // Original code should be like this:
          // this.users= data;
          // loadingPopup.dismiss();
        },
        err => console.error(err)
    );

  }
}

Answer 3

Answer №2

Success! I found that including "loading.dismiss();" inside the subscribe {} function resolved the issue.

                    this.http.get(url)
                        .subscribe(data =>{
                            this.content=JSON.parse(data['_body']).data;
                            loading.dismiss();
                        },

Answer 4

Success! I found that including "loading.dismiss();" inside the subscribe {} function resolved the issue.

                    this.http.get(url)
                        .subscribe(data =>{
                            this.content=JSON.parse(data['_body']).data;
                            loading.dismiss();
                        },

Answer 5

Answer №3

To display a Loading Controller in Ionic, you can utilize the ionViewLoaded() method which will show the loader and then dismiss it once the content is fetched from your subscription.

ionViewLoaded() {
  let loadingRef = this.loading.create({
    content: 'Custom message...',
  });

  loadingRef.present().then(() => {
    this.yourService.fetchData()
      .subscribe(res => {
        this.result = res;
      });
    loadingRef.dismiss();
  });
}

If you want to ensure that the Subscription completes before dismissing the Loader, you can structure your code like this:

ionViewLoaded() {
  let loadingRef = this.loading.create({
    content: 'Custom message...',
  });

  loadingRef.present().then(() => {
    this.yourService.fetchData()
      .subscribe(
      data => this.result = data,
      error => console.log(error),
      () => loadingRef.dismiss()
      );

  });
}

Answer 6

To display a Loading Controller in Ionic, you can utilize the ionViewLoaded() method which will show the loader and then dismiss it once the content is fetched from your subscription.

ionViewLoaded() {
  let loadingRef = this.loading.create({
    content: 'Custom message...',
  });

  loadingRef.present().then(() => {
    this.yourService.fetchData()
      .subscribe(res => {
        this.result = res;
      });
    loadingRef.dismiss();
  });
}

If you want to ensure that the Subscription completes before dismissing the Loader, you can structure your code like this:

ionViewLoaded() {
  let loadingRef = this.loading.create({
    content: 'Custom message...',
  });

  loadingRef.present().then(() => {
    this.yourService.fetchData()
      .subscribe(
      data => this.result = data,
      error => console.log(error),
      () => loadingRef.dismiss()
      );

  });
}

Answer 7

Answer №4

To properly handle the dismiss event in the latest version of Ionic, you need to follow these steps:

const loading = this.loadingCtrl.create({
    content: "Connecting to Migal server..."
});

loading.present();

loading.onDidDismiss().then(() => {
     // Perform desired actions here
});

Answer 8

To properly handle the dismiss event in the latest version of Ionic, you need to follow these steps:

const loading = this.loadingCtrl.create({
    content: "Connecting to Migal server..."
});

loading.present();

loading.onDidDismiss().then(() => {
     // Perform desired actions here
});

Having Trouble with Ionic 2's Loading Controller

Answer №1

Answer №2

Answer №3

Answer №4

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