Understanding of React Native Switch

React Native Switch

This post will give you a basic Understanding of React Native switch. React Native Switch is a component for getting/showing the boolean value or to select from one out of two.

A Switch is a controlled component that requires a callback onValueChange that updates the value prop in order for the component to reflect user actions. If the value prop is not updated, the component will continue to render the supplied value prop instead of the expected result of any user actions.

To Import Switch in Code

import { Switch} from 'react-native'

Render Using

<Switch onValueChange = {handlerHere} value = {Pre decided value if any}/>

To Make a React Native App

Getting started with React Native will help you to know more about the way you can make a React Native project. We are going to use react-native init to make our React Native App. Assuming that you have node installed, you can use npm to install the react-native-cli command line utility. Open the terminal and go to the workspace and run

npm install -g react-native-cli

Run the following commands to create a new React Native project

react-native init ProjectName

If you want to start a new project with a specific React Native version, you can use the --version argument:

react-native init ProjectName --version X.XX.X

react-native init ProjectName --version react-native@next

This will make a project structure with an index file named App.js in your project directory.

Code

Open App.js in any code editor and replace the code with the following code.

App.js

//This is an example code to understand Switch// 
import React from 'react';
//import react in our code. 
import { Switch, Text, View, StyleSheet } from 'react-native';
//import all the components we are going to use. 
export default class App extends React.Component {
  //Initial state false for the switch. You can change it to true just to see.
  state = {switchValue:false}
  toggleSwitch = (value) => {
      //onValueChange of the switch this function will be called
      this.setState({switchValue: value})
      //state changes according to switch
      //which will result in re-render the text
   }
  render() {
    return (
      <View style={styles.container}>
        {/*Text to show the text according to switch condition*/}
        <Text>{this.state.switchValue?'Switch is ON':'Switch is OFF'}</Text>
        {/*Switch with value set in constructor*/}
        {/*onValueChange will be triggered after switch condition changes*/}
        <Switch
          style={{marginTop:30}}
          onValueChange = {this.toggleSwitch}
          value = {this.state.switchValue}/>
      </View>
    );  
  } 
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
  }
});

To Run the React Native App

Open the terminal again and jump into your project using.

cd ProjectName

To run the project on an Android Virtual Device or on real debugging device

react-native run-android

or on the iOS Simulator by running

react-native run-ios (macOS only).

Output Screenshot

Output in Online Emulator

That was the React Native Switch. If you have any doubts or you want to share something about the topic you can comment below or contact us here. The remaining components will be covered in the next article. Stay tuned!

Hope you liked it. 🙂