"Implementing Ionic 2's OnScroll Event for Smooth Navigation

Question

"Implementing Ionic 2's OnScroll Event for Smooth Navigation

I'm trying to figure out how to detect when a user scrolls in Ionic 2. In simple terms, I want to perform an action when the user scrolls down the page.

It would be really helpful if someone could provide some examples.

UPDATE:

In my constructor, I have this code snippet where I want to close the keyboard when the page is scrolled because it's sometimes left open without any other way to close it.

import { Component, ViewChild } from '@angular/core';
import { NavController, NavParams, Content } from 'ionic-angular';
import { Keyboard } from '@ionic-native/keyboard';

export class SearchPage {

  @ViewChild(Content)
  content:Content;

  constructor(public keyboard: Keyboard, public formBuilder: FormBuilder, public navCtrl: NavController, public navParams: NavParams, public apiAuthentication: ApiAuthentication, private http: Http) {

    this.content.ionScroll.subscribe((data)=>{
      this.keyboard.close();
    });
  }
}

But I'm getting an error that says

Cannot read property 'ionScroll' of undefined

. Am I putting it in the wrong place?

angular typescript ionic-framework ionic2

Answer 1

Answer №1

To receive updates on content events, you can subscribe to them.

There are 3 output events for content:

ionScroll - Emitted on every scroll event.
ionScrollEnd - Emitted when scrolling ends.
ionScrollStart - Emitted when the scrolling first starts.

To listen to an event programatically:

@ViewChild(Content)
content: Content;
// ...
ngAfterViewInit() {
  this.content.ionScrollEnd.subscribe((data)=>{
    //... perform actions
  });
}

Or, you can handle it directly from the DOM:

<ion-content (ionScroll)="onScroll($event)">

For Ionic 4

<ion-content [scrollEvents]="true" (ionScroll)="onScroll($event)">

Answer 2

To receive updates on content events, you can subscribe to them.

There are 3 output events for content:

ionScroll - Emitted on every scroll event.
ionScrollEnd - Emitted when scrolling ends.
ionScrollStart - Emitted when the scrolling first starts.

To listen to an event programatically:

@ViewChild(Content)
content: Content;
// ...
ngAfterViewInit() {
  this.content.ionScrollEnd.subscribe((data)=>{
    //... perform actions
  });
}

Or, you can handle it directly from the DOM:

<ion-content (ionScroll)="onScroll($event)">

For Ionic 4

<ion-content [scrollEvents]="true" (ionScroll)="onScroll($event)">

Answer 3

Answer №2

One way to handle the scroll event is by using the ngOnInit method :

ngOnInit() {
   if (this.content) {
      this.content.ionScroll.subscribe((data)=>
        this.keyboard.close();
      });
    }
  }

Answer 4

One way to handle the scroll event is by using the ngOnInit method :

ngOnInit() {
   if (this.content) {
      this.content.ionScroll.subscribe((data)=>
        this.keyboard.close();
      });
    }
  }

Answer 5

Answer №3

If you find yourself within a custom directive, consider using the following snippet of code:

import { Renderer2 } from '@angular/core';
...
constructor(private renderer: Renderer2) {}

ngOnInit() {
    this.renderer.listen(this.myElement, 'scroll', (event) => {
        // Perform actions using 'event'
        console.log(this.myElement.scrollTop);
    });
}

Answer 6

If you find yourself within a custom directive, consider using the following snippet of code:

import { Renderer2 } from '@angular/core';
...
constructor(private renderer: Renderer2) {}

ngOnInit() {
    this.renderer.listen(this.myElement, 'scroll', (event) => {
        // Perform actions using 'event'
        console.log(this.myElement.scrollTop);
    });
}

"Implementing Ionic 2's OnScroll Event for Smooth Navigation

Answer №1

Answer №2

Answer №3

Similar questions

"Element UI, featuring a wide array of components, contributing to bloated bundle sizes

What is the best way to extract a specific property from an object?

The ngOnChanges lifecycle hook does not trigger when the same value is updated repeatedly

What is the method for retrieving the currently selected value in a MultiColumnComboBox within Kendo for Angular?

In Angular 2, the process of activating an authentication popup or modal can be achieved by following these

What steps should I take to resolve the Heroku TypeScript and Node.js build error I'm experiencing?

Confused about how to correctly utilize template variables within an *ngIf condition

Is there a method to create a typecheck for hasOwnProperty?

Issue with Angular data display in template

Connecting the Mean Stack server with Ionic

After downloading Angular Cli using the command (npm install -g @angular/cli), the error message "ng is not recognized as an internal or external command" popped

Angular 4: Exploring the Contrasts between ngDoCheck and ngAfterViewChecked

Trouble with Angular not redirecting to external URLs using anchor tags

During the construction of an Ionic app, you may notice that certain files and folders with names beginning with "._" appear before encountering an error

Create a unique CSS class and apply it to all elements within the angular-formio/formio framework

Concern regarding response and emotional reaction triggered by a third-party package

Exploring the Ways to Determine Array Type in Typescript Generics

Tips for adjusting the maximum characters per line in tinyMCE 5.0.11

Issue TS2345: Cannot assign type 'UserDataSource' to type '{}'[] in the parameter

When someone visits a site using Next.js, the redirect feature may successfully load the site, but it fails to actually