React Native Animation

React Native Animations provide an extra effect and great user experience in the app. Animations convey physically believable motion in your interface.

There are two types of complementary animation systems in React Native. These are:

Animated: The Animated API is used to interactive control the specific values. It focuses on declarative relationships between inputs and outputs. It has a start and stop methods to control the time-based animation execution.

Animated exports four different animated components as View, Text, Image and ScrollView. We can also create our own animated component using Animated.createAnimatedComponent().

LayoutAnimated: The LayoutAnimated is used to animate the global layout transactions.

Animated Methods

Methods	Description
Animated.timing()	It animates a value over time using various easing curve, or by using own function.
Animated.event()	It maps event directly to animated values.
Animated.spring()	It animate the valueIt tracks the velocity of state to create fluid motion as toValue updates.
Animated.decay()	It starts the animations with initial velocity and gradually goes slows to stop.

React Native Animation Example 1 (Animated.timing())

In this example, we will create a spinning animation on image using Animated.timing().

App.js

import React, { Component } from 'react';
import {StyleSheet, AppRegistry,Text, View,Animated,Easing} from 'react-native';

export default class DisplayAnImage extends Component {
    constructor () {
        super()
        this.spinValue = new Animated.Value(0)//declare spinValue as a new Animated.Value and pass 0 (zero) in it.
    }
    componentDidMount () {
        this.spin()
    }
    //create a spin method and call it from componentDidMount
    spin () {
        this.spinValue.setValue(0) //set spinValue to 0 (zero)
        Animated.timing(    //calling Animated.timing() method, it takes two arguments:
            this.spinValue, // value
            {           // and config object
                toValue: 1, //and setting spinValue to 1
                duration: 4000, //within 4000 milliseconds
                easing: Easing.linear
            }
        ).start(() => this.spin())
    }
    render () {
        const spin = this.spinValue.interpolate({
            inputRange: [0, 1],
            outputRange: ['0deg', '360deg']
        })
        return (
            <View style={styles.container}>
                <Animated.Image
                    style={{
                        width: 227,
                        height: 200,
                        transform: [{rotate: spin}] }}
                    source={require('MyReactNativeApp/img/react-logo.png')}
                />
            </View>
        )
    }
}
const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center'
    }
})
// skip this line if you are using Create React Native App

AppRegistry.registerComponent('DisplayAnImage', () => DisplayAnImage);

The interpolate() method call any Animated.Value. It interpolates the value before updating the property. In above example, we map 0 (zero) degrees to 360 degrees.

We pass an inputRange [0,1] and get the outputRange['0deg', '360deg'] array.

Output:

React Native Animation Example 2 (Animated.timing())

In this example, we declare a single animated value this.aninatedValue and use it with interpolate to create multiple animations, such as: marginLeft, opacity, fontSize, and rotate. We will interpolate these properties for styling such as opacity, margins, text sizes, and rotation properties.

App.js

import React, { Component } from 'react';
import {StyleSheet, AppRegistry,Text, View,Animated,Easing} from 'react-native';

export default class DisplayAnImage extends Component {
    constructor () {
        super()
        this.animatedValue = new Animated.Value(0)
    }
    componentDidMount () {
        this.animate()
    }//animate method is call from componentDidMount
    animate () {
        this.animatedValue.setValue(0)
        Animated.timing(
            this.animatedValue,
            {
                toValue: 1,
                duration: 2000,
                easing: Easing.linear
            }
        ).start(() => this.animate())
    }

    render() {
        const marginLeft = this.animatedValue.interpolate({
            inputRange: [0, 1],
            outputRange: [0, 300]
        })
        const opacity = this.animatedValue.interpolate({
            inputRange: [0, 0.5, 1],
            outputRange: [0, 1, 0]
        })
        const movingMargin = this.animatedValue.interpolate({
            inputRange: [0, 0.5, 1],
            outputRange: [0, 300, 0]
        })
        const textSize = this.animatedValue.interpolate({
            inputRange: [0, 0.5, 1],
            outputRange: [18, 32, 18]
        })
        const rotateX = this.animatedValue.interpolate({
            inputRange: [0, 0.5, 1],
            outputRange: ['0deg', '180deg', '0deg']
        })


        return (
            <View style={styles.container}>
                <Animated.View //returns Animated.View
                    style={{
                        marginLeft,
                        height: 30,
                        width: 40,
                        backgroundColor: 'red'}} />
                <Animated.View
                    style={{
                        opacity,
                        marginTop: 10,
                        height: 30,
                        width: 40,
                        backgroundColor: 'blue'}} />
                <Animated.View
                    style={{
                        marginLeft: movingMargin,
                        marginTop: 10,
                        height: 30,
                        width: 40,
                        backgroundColor: 'orange'}} />
                <Animated.Text // returns Animated.Text
                    style={{
                        fontSize: textSize,
                        marginTop: 10,
                        color: 'green'}} >
                    Animated Text!
                </Animated.Text>
                <Animated.View 
                    style={{
                        transform: [{rotateX}],
                        marginTop: 50,
                        height: 30,
                        width: 40,
                        backgroundColor: 'black'}}>
                    <Text style={{color: 'white'}}>Hello from TransformX</Text>
                </Animated.View>
            </View>
        )
    }
}
const styles = StyleSheet.create({
    container: {
        flex: 1,
        paddingTop: 150
    }
}) 
// skip this line if you are using Create React Native App
AppRegistry.registerComponent('DisplayAnImage', () => DisplayAnImage);

Output:

LayoutAnimation API

LayoutAnimation allow to globally configure, create, and update animations. This will be used for all views in the next render/layout cycle.

The LayoutAnimation is quite useful, it has much less control than Animated and other animation libraries.

To use this API in Android we need to set the following flags via UIManager:

UIManager.setLayoutAnimationEnabledExperimental &&
  UIManager.setLayoutAnimationEnabledExperimental(true);

React Native LayoutAnimation Example

In this example, we create a TouchableOpacity and a View component. On pressing the TouchableOpacity component calls the _onPress() method and it animates the View component by increases width and height of View by 15 unit.

import React from 'react';
import {
    NativeModules,
    LayoutAnimation,
    Text,
    TouchableOpacity,
    StyleSheet,
    View,
} from 'react-native';

const { UIManager } = NativeModules;

UIManager.setLayoutAnimationEnabledExperimental &&
UIManager.setLayoutAnimationEnabledExperimental(true);

export default class App extends React.Component {
    state = {
        w: 100,
        h: 100,
    };

    _onPress = () => {
        // Animate the update
        LayoutAnimation.spring();
        this.setState({w: this.state.w + 15, h: this.state.h + 15})
    }

    render() {
        return (
            <View style={styles.container}>
                <View style={[styles.box, {width: this.state.w, height: this.state.h}]} />
                <TouchableOpacity onPress={this._onPress}>
                    <View style={styles.button}>
                        <Text style={styles.buttonText}>Press me!</Text>
                    </View>
                </TouchableOpacity>
            </View>
        );
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        alignItems: 'center',
        justifyContent: 'center',
    },
    box: {
        width: 200,
        height: 200,
        backgroundColor: 'blue',
    },
    button: {
        backgroundColor: 'green',
        paddingHorizontal: 20,
        paddingVertical: 15,
        marginTop: 15,
    },
    buttonText: {
        color: '#fff',
        fontWeight: 'bold',
    },
});

Output: