Kendo UI Draggable

A repository for the cross-platform abstraction for drag sequences.

* Overview
* Installation
* Basic Usage
* Features
* What's Next
* Dragging on iOS/Android
* Preventing Selection
* Browser Support

Overview

The Kendo UI Draggable component handles mouse drags and touch sequences on mobile devices.

A drag sequence means:

- Mouse click, drag, release for desktop devices.
- Touch press, drag, release for mobile devices.

Installation

The library is published as a scoped NPM package in the NPMJS Telerik account.

``bash
npm install --save '@telerik/kendo-draggable';
`

Basic Usage

The draggable class constructor accepts an object with three optional event handler callbacks—press, drag, and release.

`javascript
import Draggable from '@telerik/kendo-draggable';

const draggable = new Draggable({
press: function(e) {
console.log("pressed", e.pageX, e.pageY);
},
drag: function(e) {
console.log("drag", e.pageX, e.pageY);
},
release: function(e) {
console.log("release", e.pageX, e.pageY);
}
});

draggable.bindTo(document.getElementById("my-element"));
`

The Draggable may be re-bound to another element—the event handlers will be automatically unbound from the previous one.

`javascript
draggable.bindTo(document.getElementById("another-element"));
`

The draggable object persists a reference to the currently bound element. That is why it should be destroyed when or if the corresponding element is removed from the document.

`javascript
draggable.destroy();
`

Features

The Kendo UI Draggable supports:

- Mouse events
- Touch events
- Pointer events
- Handling of multiple touches. Rather, not getting confused by them.

Dragging on iOS/Android

Handling the drag sequence on mobile devices may require the disabling of the touch-based scrolling. The Draggable will not do that out of the box. The recommended way to handle this issue is by setting a touch-action CSS property. Depending on the type of drags that are handled, you may need touch-action: none, touch-action: pan-y, or touch-action: pan-x.

> The touch-action setting does not work for iOS yet. While the iOS 9.3 version, which has been released recently, provides limited support, pan-x and pan-y do not work. To disable the touch-based scrolling in iOS, prevent the touchstart event:

`html



`

Preventing Selection

The dragging of elements that contain text activates the browser text selection, which, in most cases, is not desirable. To avoid this behavior, use the user-select: none CSS property with its respective browser prefixes.

Mouse-Only mode

To ignore all touch and pointer events, set mouseOnly to true. This is useful when you want to keep the default touch-drag behavior, e.g. horizontal scroll.

`javascript
import Draggable from '@telerik/kendo-draggable';

const draggable = new Draggable({
mouseOnly: true,
press: function(e) {
console.log("pressed", e.pageX, e.pageY);
},
drag: function(e) {
console.log("drag", e.pageX, e.pageY);
},
release: function(e) {
console.log("release", e.pageX, e.pageY);
}
});

draggable.bindTo(document.getElementById("my-element"));
``

Browser Support

- Google Chrome
- Firefox
- Safari (OS X)
- Safari (iOS)
- Chrome (Android)
- IE/Edge