README.md

react-native-wheely

An all JavaScript, highly customizable wheel picker for react native.

Installation

Install with npm

npm install --save react-native-wheely

Install with yarn

yarn add react-native-wheely

Usage

import React, { useState } from 'react';
import WheelPicker from 'react-native-wheely';

function CityPicker() {
  const [selectedIndex, setSelectedIndex] = useState(0);

  return (
    <WheelPicker
      selectedIndex={selectedIndex}
      options={['Berlin', 'London', 'Amsterdam']}
      onChange={(index) => setSelectedIndex(index)}
    />
  );
}

Props

Name	Type	Description
options	string[]	Options to be displayed in the wheel picker. Options are rendered from top to bottom, meaning the first item in the options will be at the top and the last at the bottom.
selectedIndex	number	Index of the currently selected option.
onChange	(index: number) => void	Handler that is called when the selected option changes.
visibleRest	number	Amount of additional options that are visible in each direction. Default is 2, resulting in 5 visible options.
itemHeight	number	Height of each option in the picker. Default is 40.
itemStyle	StyleProp<ViewStyle>	Style for the option's container.
itemTextStyle	StyleProp<TextStyle>	Style for the option's text.
containerStyle	StyleProp<ViewStyle>	Style of the picker.
selectedIndicatorStyle	StyleProp<ViewStyle>	Style of overlaying selected-indicator in the middle of the picker.
rotationFunction	(x: number) => number	Function to determine the x rotation of items based on their current distance to the center (which is x). Default is
scaleFunction	(x: number) => number	Function to determine the scale of items based on their current distance to the center (which is x). Default is
opacityFunction	(x: number) => number	Function to determine the opacity of items based on their current distance to the center (which is x). Default is
decelerationRate	"normal", "fast", number	How quickly the underlying scroll view decelerates after the user lifts their finger. See the ScrollView docs. Default is "fast".
containerProps	ViewProps	Props that are applied to the container which wraps the FlatList and the selected indicator.
flatListProps	FlatListProps	Props that are applied to the FlatList.

Memoization

The individual items in the picker (<WheelPickerItem />) are strictly memoized, meaning that they will not rerender after the initial render. Rerendering the picker items uncontrollably would lead to bad performance with large number of options. Item styles, animation functions and other parameters of items therefore must be static and changes to them after the initial render will have no effect.