Using NavParams within a service component,

Question

Using NavParams within a service component,

I'm facing a challenge in accessing NavParams within a provider, and simply importing NavParams is not solving the issue.

Here's a brief overview of my application: users input their name and address, a pin is dropped on the map based on the address provided. When the user clicks on the pin, an alert displaying the name associated with the pin pops up.

This is the section from my create-event.ts where I push the event name:

toMap() {
  this.navCtrl.push('MapPage', {eName: this.eventDetail.eventName});
}

The data is then retrieved in Map.ts and pushed to markers.ts:

public eName: string;

constructor (...) {
this.eName = this.navParams.get('eName');
}

addMarker() {
// Function code here
}

geoCodeandAdd(address) {
// Function code here
}

loadMarkers() {
// Function code here
}

Next, let's take a look at the marker provider .ts file:

// Marker Provider code here

Following that, there is a stack trace error detailing issues related to NavController:

Error message here

In conclusion, I am exploring ways to effectively utilize navparams within the provider for smoother functionality.

typescript firebase-realtime-database ionic3 leaflet

Answer 1

Answer №1

There is no need for navParams when passing values to the provider. Simply pass it as an argument to the relevant method in your provider.

In your Map.ts:

public eName: string;

constructor (...) {
this.eName = this.navParams.get('eName');
}

addMarker() {
let prompt = this.alertCtrl.create({
  title: 'Add Marker',
  message: "Enter Adress",
  inputs: [
    {
      name: 'Address',
      placeholder: 'Enter Address'
    },
  ],
  buttons: [
    {
      text: 'Cancel',
      handler: data => {
        console.log('Cancel clicked');
      }
    },
    {
      text: 'Save',
      handler: data => {

        this.geoCodeandAdd(data.address);
        this.retrieveAddress(data.address);
      }
    }
  ]
});
prompt.present();
}
geoCodeandAdd(address) {
this.nativeGeocoder.forwardGeocode(address)
  .then((coordinates: NativeGeocoderForwardResult[]) => {

  // pass eName as an argument here:
  this.markersProvider.saveMarker(coordinates[0], this.eName); 
})
.catch((error: any) => console.log(error));
}
  loadMarkers() {
this.markersProvider.getAllMarkers().subscribe((markers: any) => {
  markers.forEach(singlemarker => {
    let markerGroup = leaflet.featureGroup();

    let marker: any = leaflet
      .marker([singlemarker.latitude, singlemarker.longitude])
      .on("click", () => {
        alert(singlemarker.message);
      });
    markerGroup.addLayer(marker);
    this.map.addLayer(markerGroup);
  });
});
}

Now in your provider, update the method that uses eName:

// remove this: import { NavController, NavParams } from 'ionic-angular';
import { Injectable } from '@angular/core';
import { AngularFirestore } from "angularfire2/firestore";

@Injectable()
export class MarkersProvider {
  
  constructor(private afs: AngularFirestore) {
    console.log("Hello MarkersProvider Provider");
  }

  // add argument to this method:
  saveMarker(coords, eName) {
    this.afs
      .collection("markers")
      .add({
        latitude: coords.latitude,
        longitude: coords.longitude,
        message: eName,
      })
      .then(() => {
        alert("Added");
      });
  }

  getAllMarkers() {
    return this.afs.collection("markers").valueChanges();
  }
}

Answer 2

There is no need for navParams when passing values to the provider. Simply pass it as an argument to the relevant method in your provider.

In your Map.ts:

public eName: string;

constructor (...) {
this.eName = this.navParams.get('eName');
}

addMarker() {
let prompt = this.alertCtrl.create({
  title: 'Add Marker',
  message: "Enter Adress",
  inputs: [
    {
      name: 'Address',
      placeholder: 'Enter Address'
    },
  ],
  buttons: [
    {
      text: 'Cancel',
      handler: data => {
        console.log('Cancel clicked');
      }
    },
    {
      text: 'Save',
      handler: data => {

        this.geoCodeandAdd(data.address);
        this.retrieveAddress(data.address);
      }
    }
  ]
});
prompt.present();
}
geoCodeandAdd(address) {
this.nativeGeocoder.forwardGeocode(address)
  .then((coordinates: NativeGeocoderForwardResult[]) => {

  // pass eName as an argument here:
  this.markersProvider.saveMarker(coordinates[0], this.eName); 
})
.catch((error: any) => console.log(error));
}
  loadMarkers() {
this.markersProvider.getAllMarkers().subscribe((markers: any) => {
  markers.forEach(singlemarker => {
    let markerGroup = leaflet.featureGroup();

    let marker: any = leaflet
      .marker([singlemarker.latitude, singlemarker.longitude])
      .on("click", () => {
        alert(singlemarker.message);
      });
    markerGroup.addLayer(marker);
    this.map.addLayer(markerGroup);
  });
});
}

Now in your provider, update the method that uses eName:

// remove this: import { NavController, NavParams } from 'ionic-angular';
import { Injectable } from '@angular/core';
import { AngularFirestore } from "angularfire2/firestore";

@Injectable()
export class MarkersProvider {
  
  constructor(private afs: AngularFirestore) {
    console.log("Hello MarkersProvider Provider");
  }

  // add argument to this method:
  saveMarker(coords, eName) {
    this.afs
      .collection("markers")
      .add({
        latitude: coords.latitude,
        longitude: coords.longitude,
        message: eName,
      })
      .then(() => {
        alert("Added");
      });
  }

  getAllMarkers() {
    return this.afs.collection("markers").valueChanges();
  }
}

Using NavParams within a service component,

Answer №1

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