2016: Harnessing Ionic2, Angular2, and TypeScript to Retrieve a DOM Element in a Function

Having trouble finding the most updated way to access a DOM element with Angular2, Ionic2, and TypeScript.

Question: How can I access sketchElement in the sign() function?

Template in Settings.ts:

<button full class="top-button-margin" (click)="sign()">
  Sign
  <ion-icon name="create"></ion-icon>
</button>
<img id="sketchElement" src="img/logo.png" padding *ngIf="showSignatureView">

Settings.ts class:

@Page({
  templateUrl: 'build/pages/settings/settings.html'
})
export class SettingsPage {

  private currentUser: User = <User>{};
  private loggingOut: boolean = false;
  private currentConnection: string = "";
  private showSignatureView: boolean = false;

  constructor(
    private _platform: Platform,
    private _nav: NavController,
    private _events: Events,
    private _LoginService: LoginService,
    private _SessionService: SessionService,
    private _UIService: UIService) {

  }

  sign() {
    // Need to find a way to access sketchElement and its properties here.      
  }
}

Answer №1

To implement this functionality, utilize the ViewChild decorator. Start by including the following code snippet:

<img id="sketchElement"
     #sketchElement
     src="img/logo.png" padding *ngIf="showSignatureView">

Next, define the corresponding property in your component:

@Page({
  templateUrl: 'build/pages/settings/settings.html'
})
export class SettingsPage {
  @ViewChild('sketchElement')
  sketchElement:ElementRef;

  ngAfterViewInit() {
    // Utilize the sketchElement here
  }
}

For a demonstration, refer to this Plunker example: http://plnkr.co/edit/0TV3ppA0Gpwr5CjOWlAu?p=preview.

If you need additional assistance, check out this related question:

  • How to Call a Function in a Child Angular2 Component?

Answer №2

Although I am still relatively new to Ionic and Angular myself, I recently observed someone using Directives with ElementRef in a project involving d3.

import * as d3 from 'd3';

In this particular scenario, they included an image svg element and implemented the following code within the Directive constructor:

import {ElementRef} from '@angular/core';
constructor (private elementRef : ElementRef) {
   let el = this.elementRef.nativeElement;
   var svg = d3.select(el).append('svg');
} 

You may consider incorporating something similar into your constructor for added functionality.

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