ionic 4 - scroll to an x,y coordinate on my webView using typeScript

问题

I am making a custom map in my application. Which is essentially a large map image where I move a small avatar image over the large map image based on a gps location.

I allow the user to scroll around the map to look at places off the screen.

I now want to include a button which will center the user back on their location. but it is not working, I have tried using:

  window.moveTo()
  window.scrollTo()

but nothing happens. Can anyone assist with this?

html

 <ion-content padding id=ionScroll scrollX="true" scrollY="true">

  <div id = "main" >
    <img class = "map"
    id = "map"
    src = "../../assets/img/limerickmap.JPG"
    alt = "map"/> 
    <img class = "avatar"
    id = "avatar"
    src = "../../assets/img/satan.png"
    alt = "avatar" />
  </div>
  <ion-fab vertical="bottom" horizontal="end" slot="fixed">
    <ion-fab-button (click) = "centreMap()">
      <ion-icon name="compass"></ion-icon>
    </ion-fab-button>
  </ion-fab>

   </ion-content>

Typescript

 ngOnInit() {
      ionScroll = window.document.getElementById("ionScroll");
 }

 centreMap() {
     ionScroll.scrollTo(avatar.style.left , avatar.style.top);
     console.log("TEST scroll" +avatar.style.left+"  "+avatar.style.top)
 }

回答1:

Trying to set the id isn't the right way I don't think.

Freaky Jolly has a tutorial explaining how to scroll to an X/Y coord.

First, you need scrollEvents on the ion-content:

<ion-header>
  <ion-toolbar>
    <ion-title>
      Ion Content Scroll
    </ion-title>
  </ion-toolbar>
</ion-header>

<ion-content [scrollEvents]="true">
  <div style="height: 50px;width:600px;" text-right>
    <ion-button (click)="ScrollToPoint(-300, -120)">
      Scroll To Point Right
    </ion-button>
  </div>
</ion-content>

In the code you need to use a @ViewChild to get a code reference to the ion-content then you can use its ScrollToPoint() api:

import { Component, ViewChild } from '@angular/core';
import { IonContent } from '@ionic/angular';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage {
  @ViewChild(IonContent) content: IonContent;

  constructor(
  ){
  }

  ScrollToPoint(X,Y){
    this.content.scrollToPoint(X,Y,1500);
  }
}

I've simplified the article so you will need to put some content in that adds scrollbars to the page if you want this to actually work.

来源：https://stackoverflow.com/questions/56834121/ionic-4-scroll-to-an-x-y-coordinate-on-my-webview-using-typescript

标签

html

typescript

ionic4