Category: 2. Guides

The Image component is used to display the image on the screen. The image can be loaded from different source such as static resources, temporary local files, local disc, network images, etc.

Static Image Resources

The static images are added in app by placing it in somewhere in the source code directory and provide its path as:

1. <Image source={require(‘./icon_name.png’)} />  

In the above syntax, the packager will look for icon_name.png in the same folder as the component that requires it. To load the image on a specific platform, it should be named by specifying the platform as extensions such as icon_name.ios.png and icon_name.android.png.

Images from Hybrid App’s Resources

The hybrid app which is built (UI) by using both React Native and platform code can also uses the image which is bundled into the app.

The image included through Xcode asset catalogs or in Android drawable folder are consumes without their extension.

1. <Image source={{uri: ‘icon_name’}} style={{width: 60, height: 60}} />  

The images within the Android assets folder, use the scheme: asset:/ with image extension.

1. <Image source={{uri: ‘asset:/icon_name.png’}} style={{width: 60, height: 60}} />  

Network Images

The dynamic and network images are also be displayed in the Image component. To access the network image, it is required to specify the dimensions of image manually.

It is recommended to use https in order to satisfy the App Transport Security requirements on iOS.

1. // GOOD  
2. <Image source={{uri: ‘https://url_of_image.png’}}  
3.        style={{width: 60, height: 60}} />  
4.   
5. // BAD  
6. <Image source={{uri: ‘https://url_of_image.png’}} />  

Uri Data Images

The encoded image data use the “data:” uri scheme in the image component. The data image also required to specify the dimension of the image.

1. <Image  
2.     style={{width: 66, height: 66}}  
3.     source={{uri: ‘data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADMAAAAzCAYAAAA6oTAqAAAAEXRFWHRTb2Z0d2FyZQBwbmdjcnVzaEB1SfMAAABQSURBVGje7dSxCQBACARB+2/ab8BEeQNhFi6WSYzYLYudDQYGBgYGBgYGBgYGBgYGBgZmcvDqYGBgmhivGQYGBgYGBgYGBgYGBgYGBgbmQw+P/eMrC5UTVAAAAABJRU5ErkJggg==’}}  
4. />  

Background Image via Nesting

The background image is set using the ImageBackground component. It is also the same props as Image. We can add any component as children on the top of it.

1. return (  
2.   <ImageBackground source={…} style={{width: ‘100%’, height: ‘100%’}}>  
3.     <Text>Inside</Text>  
4.   </ImageBackground>  
5. );  

React Native Image Example

App.js

1. import React, { Component } from ‘react’;  
2. import {StyleSheet, AppRegistry,Text, View, Image,ImageBackground } from ‘react-native’;  
3.   
4. export default class DisplayAnImage extends Component {  
5.     render() {  
6.         return (  
7.             <ImageBackground source = {{uri:’https://www.javatpoint.com/tutorial/react-native/images/react-native-tutorial.png’}}  
8.                              style={{width: ‘100%’, height: ‘100%’}}>  
9.                <Image source={require(‘./favicon.png’)} />  
10.                 <Image  
11.                     source={require(‘/ReactNative/MyReactNativeApp/img/favicon.png’)}  
12.                 />  
13.   
14.                 <Image  
15.                     source={require(‘MyReactNativeApp/img/favicon.png’)}  
16.                 />  
17.                 <Image source={{uri: ‘asset:/images/favicon.png’}} style={{width: 60, height: 60}} />  
18.                 <Image source = {{uri:’https://www.javatpoint.com/images/logo/jtp_logo.png’}}  
19.                        style = {{ width: ‘80%’, height: 70 }}  
20.                 />  
21.                 <Image  
22.                     style={{width: 60, height: 60}}  
23.                     source={{uri: ‘data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADMAAAAzCAYAAAA6oTAqAAAAEXRFWHRTb2Z0d2FyZQBwbmdjcnVzaEB1SfMAAABQSURBVGje7dSxCQBACARB+2/ab8BEeQNhFi6WSYzYLYudDQYGBgYGBgYGBgYGBgYGBgZmcvDqYGBgmhivGQYGBgYGBgYGBgYGBgYGBgbmQw+P/eMrC5UTVAAAAABJRU5ErkJggg==’}}  
24.                 />  
25.   
26.             </ImageBackground>  
27.   
28.         );  
29.     }  
30. }  
31. // skip this line if using Create React Native App  
32. AppRegistry.registerComponent(‘DisplayAnImage’, () => DisplayAnImage);  

Output:

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.
• LayoutAnimated: The LayoutAnimated is used to animate the global layout transactions.
• 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);  
• 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);  
• UIManager.setLayoutAnimationEnabledExperimental &&  
•   UIManager.setLayoutAnimationEnabledExperimental(true);  
• 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’,  
•     },  
• });