Verify Ionic storage for an item

Question

Verify Ionic storage for an item

Is there a way to display an introductory slider only once for new users when they install the app?

Solution

If the user installs the app, set an item in the storage called intro with a value of false
When the user opens the app, check the intro item. If the value is false, show the intro page. If it's true, proceed with routing and load the main page route.

Challenge

I've attempted various methods to achieve this objective, but all have failed due to the absence of an item named intro in the storage.

Implementation

Here are my attempts so far (all located in the app.component.ts file)

Attempt 1

import { NativeStorage } from '@ionic-native/native-storage/ngx';
constructor(
    public navCtrl: NavController,
    private storage: NativeStorage,
  ) {
    this.checkIntro();
  }

checkIntro(){
    console.log('checking intro');

    if (this.storage.getItem('intro') == undefined) {
      this.storage.setItem('intro', false);
      this.navCtrl.navigateRoot('/intro');
    } else {
      console.log('intro exists', this.storage.getItem('intro'));
    }
}

Outcome: Unsuccessful.

Attempt 2

import { NativeStorage } from '@ionic-native/native-storage/ngx';
constructor(
    public navCtrl: NavController,
    private storage: NativeStorage,
  ) {
    this.checkIntro();
  }

checkIntro(){
    console.log('checking intro');
    
    const intro = this.storage.getItem('intro');
    
    if (!intro){
      console.log('setting intro to false in storage');
      this.storage.setItem('intro', false);
      this.navCtrl.navigateRoot('/intro');
    } else {
      this.storage.getItem('intro').then(
        data => {
          console.log('intro data:', data);

          if(data == true){
            console.log('intro already seen', data);
          }else{
            this.navCtrl.navigateRoot('/intro');
            console.log('loading intro page first', data);
          }
        },
        error => {
          console.log('error occurred:', error);
        }
      )
    }
}

Outcome: Unsuccessful.

Console Output The console displays the following message (Code 2 = ITEM_NOT_FOUND):

__zone_symbol__state: 0
__zone_symbol__value: NativeStorageError
code: 2
exception: null
source: "Native"
... (truncated output for brevity)

Inquiry

How can I effectively verify the intro item in the native local storage and direct the user based on its value?

javascript angularjs ionic-framework local-storage

Answer 1

Answer №1

import {Storage} from "@ionic/storage";
constructor( public storage: Storage){
this.storage.get('intro').then(value => {
      if(value){
     //navigate to the home page
      }else{
        this.setIntro(true)
      }
    },reason => {
      this.setIntro(true)
    }).catch(err=>{
      console.log(err)
    })

}


  setIntroduction(bool:boolean){
    this.storage.set('intro',bool).then(()=>{
      //navigate to the introduction page
    }).catch(err=>{
      console.log(err)
    })
  }

Answer 2

import {Storage} from "@ionic/storage";
constructor( public storage: Storage){
this.storage.get('intro').then(value => {
      if(value){
     //navigate to the home page
      }else{
        this.setIntro(true)
      }
    },reason => {
      this.setIntro(true)
    }).catch(err=>{
      console.log(err)
    })

}


  setIntroduction(bool:boolean){
    this.storage.set('intro',bool).then(()=>{
      //navigate to the introduction page
    }).catch(err=>{
      console.log(err)
    })
  }

Answer 3

Answer №2

Your code may be encountering issues due to the use of NativeStorage instead of Ionic Storage, which is the recommended approach.

Various tutorials are available to help with this problem.

You may find this tutorial helpful:

Ionic Intro Slider for New Users | AngularFirebase

The content provided is valuable, and while initial confusion was noted, a simple page refresh resolved the loading issue.

The suggested method is to utilize a Route Guard instead of implementing it directly in the page. Construct a guard and include code similar to the following:

// ...omitted
import { Storage } from '@ionic/storage';

@Injectable({
  providedIn: 'root'
})
export class TutorialGuard implements CanActivate {

  constructor(private storage: Storage, private router: Router) {}

  async canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot
  ): Promise<boolean> {

    const isComplete = await this.storage.get('tutorialComplete');

    if (!isComplete) {
      this.router.navigateByUrl('/tutorial');
    }

    return isComplete;
  }
}

Subsequently, apply this guard to your homepage route as shown below:

import { Routes, RouterModule } from '@angular/router';
import { TutorialGuard } from './guards/tutorial.guard';

const routes: Routes = [
  {
    path: '',
    loadChildren: './tabs/tabs.module#TabsPageModule',
    canActivate: [TutorialGuard] // <-- apply here 
  },
  {
    path: 'tutorial',
    loadChildren: './tutorial/tutorial.module#TutorialPageModule'
  }
];
@NgModule(...)
export class AppRoutingModule {}

In the tutorial / introduction code, ensure to set the value of isComplete once the user completes the intro slides:

  async finish() {
    await this.storage.set('tutorialComplete', true);
    this.router.navigateByUrl('/');
  }

Answer 4

Your code may be encountering issues due to the use of NativeStorage instead of Ionic Storage, which is the recommended approach.

Various tutorials are available to help with this problem.

You may find this tutorial helpful:

Ionic Intro Slider for New Users | AngularFirebase

The content provided is valuable, and while initial confusion was noted, a simple page refresh resolved the loading issue.

The suggested method is to utilize a Route Guard instead of implementing it directly in the page. Construct a guard and include code similar to the following:

// ...omitted
import { Storage } from '@ionic/storage';

@Injectable({
  providedIn: 'root'
})
export class TutorialGuard implements CanActivate {

  constructor(private storage: Storage, private router: Router) {}

  async canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot
  ): Promise<boolean> {

    const isComplete = await this.storage.get('tutorialComplete');

    if (!isComplete) {
      this.router.navigateByUrl('/tutorial');
    }

    return isComplete;
  }
}

Subsequently, apply this guard to your homepage route as shown below:

import { Routes, RouterModule } from '@angular/router';
import { TutorialGuard } from './guards/tutorial.guard';

const routes: Routes = [
  {
    path: '',
    loadChildren: './tabs/tabs.module#TabsPageModule',
    canActivate: [TutorialGuard] // <-- apply here 
  },
  {
    path: 'tutorial',
    loadChildren: './tutorial/tutorial.module#TutorialPageModule'
  }
];
@NgModule(...)
export class AppRoutingModule {}

In the tutorial / introduction code, ensure to set the value of isComplete once the user completes the intro slides:

  async finish() {
    await this.storage.set('tutorialComplete', true);
    this.router.navigateByUrl('/');
  }

Verify Ionic storage for an item

Solution

Challenge

Implementation

Inquiry

Answer №1

Answer №2

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