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React-Tappable

Tappable component for React. Abstracts touch events to implement onTap, onPress, and pinch events.

The events mimic their native equivalents as closely as possible:

  • the baseClass (default: Tappable) has -active or -inactive added to it to enable pressed-state styling
  • the pressed state is visually cancelled if the touch moves too far away from the element, but resumes if the touch comes back again
  • when you start scrolling a parent element, the touch event is cancelled
  • if the onPress property is set, it will cancel the touch event after the press happens

When touch events are not supported, it will fall back to mouse events. Keyboard events are also supported, emulating the behaviour of native button controls.

Demo & Examples

Live demo: jedwatson.github.io/react-tappable

To build the examples locally, run:

npm install
gulp dev

Then open localhost:8000 in a browser.

Installation

The easiest way to use React-tappable is to install it from npm.

npm install react-tappable --save

Ensure to include it in your own React build process (using Browserify, etc).

You could also use the standalone build by including dist/react-tappable.js in your page; but, if you do this, make sure you have already included React, and that it is available globally.

Usage

React-tappable generates a React component (defaults to <span>) and binds touch events to it.

To disable default event handling (e.g. scrolling) set the preventDefault prop.

import Tappable from 'react-tappable';

<Tappable onTap={this.handleTapEvent}>Tap me</Tappable>

For a lighter component, you can opt-in to just the features you need:

import Tappable from 'react-tappable/lib/Tappable';
import Pinchable from 'react-tappable/lib/Pinchable';
import TapAndPinchable from 'react-tappable/lib/TapAndPinchable';

<Tappable onTap={this.handleTapEvent}>I respond to Tap events</Tappable>
<Pinchable onPinch={this.handlePinch}>I respond to Pinch events</Pinchable>
<TapAndPinchable onTap={this.handleTapEvent} onPinch={this.handlePinch}>In respond to both!</TapAndPinchable>

The TapAndPinchable component is the default one you get when you just import react-tappable.

Properties

  • activeDelay ms delay before the -active class is added, defaults to 0
  • component component to render, defaults to 'span'
  • classes optional object containing active and inactive class names to apply to the component; useful with css-modules
  • classBase base to use for the active/inactive classes
  • className optional class name for the component
  • moveThreshold px to allow movement before cancelling a tap; defaults to 100
  • pressDelay ms delay before a press event is detected, defaults to 1000
  • pressMoveThreshold px to allow movement before ignoring long presses; defaults to 5
  • preventDefault (boolean) automatically call preventDefault on all events
  • stopPropagation (boolean) automatically call stopPropagation on all events
  • style (object) styles to apply to the component

Special Events

These are the special events implemented by Tappable.

  • onTap fired when touchStart or mouseDown is followed by touchEnd or mouseUp within the moveThreshold
  • onPress fired when a touch is held for the specified ms
  • onPinchStart fired when two fingers land on the screen
  • onPinchMove fired on any movement while two fingers are on screen
  • onPinchEnd fired when less than two fingers are left on the screen, onTouchStart is triggerred, if one touch remains

Pinch Events

Pinch events come with a special object with additional data to actually be more useful than the native events:

  • touches: Array of Objects - {identifier, pageX, pageY} - raw data from the event
  • center: Object - {x, y} - Calculated center between the two touch points
  • angle: Degrees - angle of the line connecting the two touch points to the X-axis
  • distance: Number of pixels - beween the two touch points
  • displacement: Object {x, y} - offset of the center since the pinch began
  • displacementVelocity: Object {x, y} : Pixels/ms - Immediate velocity of the displacement
  • rotation: degrees - delta rotation since the beginning of the gesture
  • rotationVelocity: degrees/millisecond - immediate rotational velocity
  • zoom: Number - Zoom factor - ratio between distance between the two touch points now over initial
  • zoomVelocity: zoomFactor/millisecond - immediate velocity of zooming
  • time: milliseconds since epoch - Timestamp

Known Issues

  • The pinch implementation has not been thoroughly tested
  • Any touch event with 3 three or more touches is completely ignored.

Native Events

The following native event handlers can also be specified.

  • onKeyDown
  • onKeyUp
  • onTouchStart
  • onTouchMove
  • onTouchEnd
  • onMouseDown
  • onMouseUp
  • onMouseMove
  • onMouseOut

Returning false from onKeyDown, onMouseDown, or onTouchStart handlers will prevent Tappable from handling the event.

Changelog

See CHANGES.md

License

Copyright (c) 2017 Jed Watson. MIT