ion-smooth-scroll

An alternate to $ionicScrollDelegate.anchorScroll for smooth scrolling to given id without changing the hash of url.

Ionic component anchorScroll works unreliably. Below are few issues/limitations with it:

1. Content goes out of view : Sometimes Ionic anchorScroll scrolls beyond the target element and therefore part of content area goes out of view and doesn't become visible even when user tries to scroll. See this Github Issue or this issue. This scenario can be easily reproduced where dynamic data is rendered inside ion-content.
2. No support for css based scrollView : anchorScroll requires that the scrollable content to use ionic JS scroll (i.e ion-content or ion-scroll with no overflow-scroll = true).

This library is intended to provide the lacking functionality of anchorScroll.

ion-smooth-scroll uses Ionic $ionicScrollDelegate.scrollTo when scrollViews created by ionContent and ionScroll directives.

Install

Script file is available from a variety of sources. Choose the one that fits you.

• Github Source Code https://github.com/amiteshhh/ion-smooth-scroll/blob/master/ion-smooth-scroll.min.js
• Bower bower install ion-smooth-scroll --save
• CDN Raw Git https://rawgit.com/amiteshhh/ion-smooth-scroll/master/ion-smooth-scroll.min.js

Getting started

Add script reference to your application (normally index.html)

<script src="path/to/ion-smooth-scroll.min.js"></script>

Add the ion-smooth-scroll as a dependency in your angular module

angular.module('myApp', ['ion-smooth-scroll']);

Usage

Directive is used as an attribute. When clicked it will scroll to the target.

<ANY delegate-handle="{string}"><!-- scroll view container-->
        <ANY ion-smooth-scroll="{string}"
        delegate-handle="{string}"
        duration="{number}">
        ...
        </ANY>
</ANY>

Parameters

Param	Type	Details
ionSmoothScroll	string	id of DOM element where you want to scroll to.
delegateHandle	string	Value of delegate-handle attribute. Both scrollView container and element with ion-smooth-scroll must have this attribute even if you use css scrollView. This is used only for getting the DOM reference of scrollable container.
duration	number	Scroll transistion duration in millisecond. Applicable only for css driven scrollView container. It will also be ignored if new scroll position is less than 200px distance from current postion. You will be rarely passing this parameter :) You can also configure it at app level during angular config Phase explained later. (default: 400)

Examples

1. With ionic scrollView

<!-- Only required attributes has been shown below -->
<ion-content delegate-handle="main" id="top">
    ...
    <a ion-smooth-scroll="div1" delegate-handle="main">Go to Div 1</a>
    ...
    <div id="div1">
        ...
    </div>
    ...
</ion-content>

2. With css scrollView

The only difference is you can pass additional parameter, duration, to specify scroll transition duration

<!--Note that ion-content with overflow-scroll="true" creates the css driven scrollable area.-->
<!--<ion-content overflow-scroll="true" delegate-handle="main" id="top">
                        OR
-->

<!--This directive is not responsible for making the container scrollable. You need to write your own css.-->
<div class="my-scrollable-div" delegate-handle="main" id="top">
    ...
    <a ion-smooth-scroll="div1" delegate-handle="main">Go to Div 1</a>

    <!--Below link will reach to target in 2 seconds-->
    <button ion-smooth-scroll="div1" delegate-handle="main" duration="2000">Go to Div 1 in 2 Seconds</button>
    <!-- We can use any element -->
    ...
    <div id="div1">
        ...
    </div>
    ...
</div>

Config

it will not affect the scrollable container created by ionic-content or ion-scroll.

Configure the scroll transistion duration using ionSmoothScrollProvider.setScrollDuration method (default: 400 ms).

You will be rarely using this feature as default value suffices in most of the cases.

angular.module('myApp', ['ion-smooth-scroll'])
    .config(['ionSmoothScrollProvider', function(ionSmoothScrollProvider){
        /*uncomment below line and see it in action
        it will not affect if the scrollable container is created by ionic 
        (e.g ion-content or ion-scroll with no overflow-scroll="true")
        */
        
        ionSmoothScrollProvider.setScrollDuration(6000);        
        //ion-smooth-scroll will scroll for 6 seconds to reach the target
    }]);

Demo

Plunker Demo