React Native Web Full App Tutorial - Build a Workout App for iOS, Android, and Web

Learn to use React Native for Web to create a workout app that works on Android, iOS, and the web. The app uses Mobx, Typescript, React Navigation, React Hooks, AsyncStorage / Localstorage, and more. Once the app is complete, you will learn how to deploy it to Netlify.


💻 Code: https://github.com/benawad/react-native-web-series

⭐️ Contents ⭐️

⌨️ (0:00:00) Setting Up a React Native Web Project

⌨️ (0:09:04) Setting Up React Native Hooks

⌨️ (0:15:03) Setting Up a React Native Web Monorepo

⌨️ (0:28:24) Configuring React Native for Yarn Workspaces

⌨️ (0:39:58) How to use Mobx with React Hooks

⌨️ (0:49:15) Navigation in React Native Web

⌨️ (1:03:28) Styling a Component in React Native Web

⌨️ (1:27:40) Mobx Root Store

⌨️ (1:45:20) Workout Timer with Mobx

⌨️ (2:11:20) React Router with React Native Web

⌨️ (2:22:45) How to Persist Mobx Stores

⌨️ (2:30:47) Storing and Displaying Workout History

⌨️ (2:54:33) React Router Params in React Native Web

⌨️ (3:17:30) Floating Action Button React Native Web

⌨️ (3:34:45) Deploy React Native Web to Netlify

⭐️ Links: ⭐️

🔗 https://stronglifts.com/apps/

🔗 https://github.com/necolas/react-native-web/blob/master/docs/guides/client-side-rendering.md

🔗 VSCode settings used: https://gist.github.com/benawad/1e9dd01994f78489306fbfd6f7b01cd3


⭐️ Learn More ⭐️

React - The Complete Guide (incl Hooks, React Router, Redux)

Modern React with Redux [2019 Update]

React Native - The Practical Guide

Which should I choose: React Native or Flutter?

React Tutorial: Building and Securing Your First App

Build Progressive Web Apps with React

Build a React Calendar Component from scratch

React Native – The Future of Mobile

React Native Tutorial: SQLite Offline Android/iOS Mobile App

React Native Tutorial: SQLite Offline Android/iOS Mobile App

React Native Tutorial: SQLite Offline Android/iOS Mobile App

Table of Contents:
  • Install React App Creator and Create App
  • Add Navigation Header and required Screen
  • Install and Configure React Native SQLite Storage
  • Show List of Product
  • Show Product Details and Delete Product
  • Add Product
  • Edit Product
  • Run and Test React Native and SQLite Offline Mobile App

The following tools, frameworks, and modules are required for this tutorial:

  • Install React App Creator and Create App
  • Add Navigation Header and required Screen
  • Install and Configure React Native SQLite Storage
  • Show List of Product
  • Show Product Details and Delete Product
  • Add Product
  • Edit Product
  • Run and Test React Native and SQLite Offline Mobile App

Before start to the main steps, make sure that you have installed Node.js and can run npm in the terminal or command line. To check the existing or installed Node.js environment open the terminal/command line then type this command.

node -v
v10.15.1
npm -v
6.8.0
yarn -v
1.10.1

1. Install React App Creator and Create App

The Create React Native App is a tool for creating a React Native App. To install it, type this command in your App projects folder.

sudo npm install -g react-native-cli

Then create a React Native App using this command.

react-native init reactOffline

That command will create a React Native app then install all required modules. The app or project folder will contain these folders and files.

Next, go to the newly created React App folder.

cd reactSqlite

To run on iOS device or simulator run this command.

react-native run-ios

The simulator will open along with the new terminal window. Go to the project folder from the new terminal window then run this command.

react-native start

Right after iOS build success and React Native started, you will see this view in the iOS Simulator.

To run on Android device or simulator, make sure ADB detected the device.

adb devices
List of devices attached
J8AXGF0194047T6    device

Next, type this command to run on the Android device or simulator.

react-native run-android

It will open the new terminal windows. Just go to the project folder then type this command.

react-native start

You will see this app in your Android device.

Sometimes, if running React Native app faster than starting React-Native Javascript bundler you see this red-screen of error.

No bundle URL present.

Make sure you’re running a packager server or have included a .jsbundle file in your application bundle.

RCTFatal
__28-[RCTCxxBridge handleError:]_block_invoke
_dispatch_call_block_and_release
_dispatch_client_callout
_dispatch_main_queue_callback_4CF
__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
__CFRunLoopRun
CFRunLoopRunSpecific
GSEventRunModal
UIApplicationMain
main
start
0x0

Don’t worry, just start the Metro Bundler in the newly opened terminal window after you go to the project folder. After Metro Bundler started completely, refresh the React Native app on your device or simulator. In iOS Simulator you will see this error after refresh.

Attempting to reload bridge before it's valid: <RCTCxxBridge: 0x7ff34bc00510>. Try restarting the development server if connected.

-[RCTCxxBridge reload]
&nbsp; &nbsp; RCTCxxBridge.mm:986
-[RCTRedBox reloadFromRedBoxWindow:]
-[RCTRedBoxWindow reload]
-[UIApplication sendAction:to:from:forEvent:]
-[UIControl sendAction:to:forEvent:]
-[UIControl _sendActionsForEvents:withEvent:]
-[UIControl touchesEnded:withEvent:]
-[UIWindow _sendTouchesForEvent:]
-[UIWindow sendEvent:]
-[UIApplication sendEvent:]
__dispatchPreprocessedEventFromEventQueue
__handleEventQueueInternal
__handleEventQueueInternal
__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
__CFRunLoopDoSources0
__CFRunLoopRun
CFRunLoopRunSpecific
GSEventRunModal
UIApplicationMain
main
start
0x0

Just reload again the React Native app, you will get your React Native app running.

2. Add Navigation Header and required Screen

Above generated React Native App just show blank app with plain text. Now, we will show you how to add the Navigation Header and Home Screen for your app. So, it will look like the Native App. In the terminal or command line, type this command to install React Navigation module and don’t forget to stop the running Metro Bundler before installing the modules.

yarn add react-navigation --save
yarn add react-native-gesture-handler --save
react-native link react-native-gesture-handler

Next, create a folder for components and components files in the root of the app folder.

mkdir components
touch components/ProductScreen.js
touch components/ProductDetailsScreen.js
touch components/ProductAddScreen.js
touch components/ProductEditScreen.js

Open and edit components/ProductScreen.js then add this React codes.

import React, { Component } from 'react';
import { Button, View, Text } from 'react-native';

export default class ProductScreen extends Component {
&nbsp; static navigationOptions = {
&nbsp; &nbsp; title: 'Product List',
&nbsp; };
&nbsp; render() {
&nbsp; &nbsp; return (
&nbsp; &nbsp; &nbsp; <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
&nbsp; &nbsp; &nbsp; &nbsp; <Text>Product List</Text>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Details"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('ProductDetails')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Add Product"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('AddProduct')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Edit Product"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('EditProduct')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; );
&nbsp; }
}

Open and edit components/ProductDetailsScreen.js then add this React codes.

import React, { Component } from 'react';
import { Button, View, Text } from 'react-native';

export default class ProductDetailsScreen extends Component {
&nbsp; static navigationOptions = {
&nbsp; &nbsp; title: 'Product Details',
&nbsp; };
&nbsp; render() {
&nbsp; &nbsp; return (
&nbsp; &nbsp; &nbsp; <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
&nbsp; &nbsp; &nbsp; &nbsp; <Text>Product Details</Text>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Details... again"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.push('ProductDetails')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Home"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('Product')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go back"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.goBack()}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; );
&nbsp; }
}

Open and edit components/ProductAddScreen.js then add this React codes.

import React, { Component } from 'react';
import { Button, View, Text } from 'react-native';

export default class ProductAddScreen extends Component {
&nbsp; static navigationOptions = {
&nbsp; &nbsp; title: 'Add Product',
&nbsp; };
&nbsp; render() {
&nbsp; &nbsp; return (
&nbsp; &nbsp; &nbsp; <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
&nbsp; &nbsp; &nbsp; &nbsp; <Text>Add Product</Text>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Add Product... again"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.push('AddProduct')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Home"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('Product')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go back"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.goBack()}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; );
&nbsp; }
}

Open and edit components/ProductEditScreen.js then add this React codes.

import React, { Component } from 'react';
import { Button, View, Text } from 'react-native';

export default class ProductEditScreen extends Component {
&nbsp; static navigationOptions = {
&nbsp; &nbsp; title: 'Edit Product',
&nbsp; };
&nbsp; render() {
&nbsp; &nbsp; return (
&nbsp; &nbsp; &nbsp; <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
&nbsp; &nbsp; &nbsp; &nbsp; <Text>Add Product</Text>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Edit Product... again"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.push('EditProduct')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go to Home"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.navigate('Product')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title="Go back"
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.props.navigation.goBack()}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; );
&nbsp; }
}

Next, open and edit App.js then add replace all codes with this.

import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
import { createAppContainer, createStackNavigator } from 'react-navigation';
import ProductScreen from './components/ProductScreen';
import ProductDetailsScreen from './components/ProductDetailsScreen';
import ProductAddScreen from './components/ProductAddScreen';
import ProductEditScreen from './components/ProductEditScreen';

const RootStack = createStackNavigator(
&nbsp; {
&nbsp; &nbsp; Product: ProductScreen,
&nbsp; &nbsp; ProductDetails: ProductDetailsScreen,
&nbsp; &nbsp; AddProduct: ProductAddScreen,
&nbsp; &nbsp; EditProduct: ProductEditScreen,
&nbsp; },
&nbsp; {
&nbsp; &nbsp; initialRouteName: 'Product',
&nbsp; &nbsp; navigationOptions: {
&nbsp; &nbsp; &nbsp; headerStyle: {
&nbsp; &nbsp; &nbsp; &nbsp; backgroundColor: '#777777',
&nbsp; &nbsp; &nbsp; },
&nbsp; &nbsp; &nbsp; headerTintColor: '#fff',
&nbsp; &nbsp; &nbsp; headerTitleStyle: {
&nbsp; &nbsp; &nbsp; &nbsp; fontWeight: 'bold',
&nbsp; &nbsp; &nbsp; },
&nbsp; &nbsp; },
&nbsp; },
);

const RootContainer = createAppContainer(RootStack);

export default class App extends React.Component {
&nbsp; render() {
&nbsp; &nbsp; return <RootContainer />;
&nbsp; }
}

const styles = StyleSheet.create({
&nbsp; container: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; backgroundColor: '#fff',
&nbsp; &nbsp; alignItems: 'center',
&nbsp; &nbsp; justifyContent: 'center',
&nbsp; },
});

After Re-run the React Native app on the iOS/Android Device/Simulator you will see this updated views.

3. Install and Configure React Native SQLite Storage

Before creating an offline CRUD application using local data, we have to install the react-native-sqlite-storage and required UI/UX module.

yarn add react-native-sqlite-storage --save
yarn add react-native-elements --save
react-native link

We will use separate Class for accessing SQLite and do some CRUD (create, read, update, delete) operations. For that, create a new Javascript file on the root of the project folder.

touch Database.js

Open and edit Database.js then add this SQLite import with the configuration.

import SQLite from "react-native-sqlite-storage";
SQLite.DEBUG(true);
SQLite.enablePromise(true);

Add constant variable after that.

const database_name = "Reactoffline.db";
const database_version = "1.0";
const database_displayname = "SQLite React Offline Database";
const database_size = 200000;

Give this file a class name.

export default class Database {

}

Inside the class bracket, add a function for Database initialization that creates Database, tables, etc.

initDB() {
&nbsp; let db;
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; console.log("Plugin integrity check ...");
&nbsp; &nbsp; SQLite.echoTest()
&nbsp; &nbsp; &nbsp; .then(() => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log("Integrity check passed ...");
&nbsp; &nbsp; &nbsp; &nbsp; console.log("Opening database ...");
&nbsp; &nbsp; &nbsp; &nbsp; SQLite.openDatabase(
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; database_name,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; database_version,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; database_displayname,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; database_size
&nbsp; &nbsp; &nbsp; &nbsp; )
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .then(DB => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; db = DB;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Database OPEN");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; db.executeSql('SELECT 1 FROM Product LIMIT 1').then(() => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Database is ready ... executing query ...");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }).catch((error) =>{
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Received error: ", error);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Database not yet ready ... populating data");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('CREATE TABLE IF NOT EXISTS Product (prodId, prodName, prodDesc, prodImage, prodPrice)');
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }).then(() => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Table created successfully");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }).catch(error => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(error);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(db);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; })
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .catch(error => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(error);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; })
&nbsp; &nbsp; &nbsp; .catch(error => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log("echoTest failed - plugin not functional");
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; });
};

Add a function for close Database connection.

closeDatabase(db) {
&nbsp; if (db) {
&nbsp; &nbsp; console.log("Closing DB");
&nbsp; &nbsp; db.close()
&nbsp; &nbsp; &nbsp; .then(status => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log("Database CLOSED");
&nbsp; &nbsp; &nbsp; })
&nbsp; &nbsp; &nbsp; .catch(error => {
&nbsp; &nbsp; &nbsp; &nbsp; this.errorCB(error);
&nbsp; &nbsp; &nbsp; });
&nbsp; } else {
&nbsp; &nbsp; console.log("Database was not OPENED");
&nbsp; }
};

Add a function to get the list of products.

listProduct() {
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; const products = [];
&nbsp; &nbsp; this.initDB().then((db) => {
&nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('SELECT p.prodId, p.prodName, p.prodImage FROM Product p', []).then(([tx,results]) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log("Query completed");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var len = results.rows.length;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; for (let i = 0; i < len; i++) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let row = results.rows.item(i);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(`Prod ID: ${row.prodId}, Prod Name: ${row.prodName}`)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; const { prodId, prodName, prodImage } = row;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; products.push({
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prodId,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prodName,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prodImage
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(products);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(products);
&nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; }).then((result) => {
&nbsp; &nbsp; &nbsp; &nbsp; this.closeDatabase(db);
&nbsp; &nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; });
&nbsp; }); &nbsp;
}

Add a function to get Product by ID.

productById(id) {
&nbsp; console.log(id);
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; this.initDB().then((db) => {
&nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('SELECT * FROM Product WHERE prodId = ?', [id]).then(([tx,results]) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(results);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(results.rows.length > 0) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; let row = results.rows.item(0);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(row);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; }).then((result) => {
&nbsp; &nbsp; &nbsp; &nbsp; this.closeDatabase(db);
&nbsp; &nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; });
&nbsp; }); &nbsp;
}

Add a function to save a new product to the SQLite database.

addProduct(prod) {
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; this.initDB().then((db) => {
&nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('INSERT INTO Product VALUES (?, ?, ?, ?, ?)', [prod.prodId, prod.prodName, prod.prodDesc, prod.prodImage, prod.prodPrice]).then(([tx, results]) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(results);
&nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; }).then((result) => {
&nbsp; &nbsp; &nbsp; &nbsp; this.closeDatabase(db);
&nbsp; &nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; });
&nbsp; }); &nbsp;
}

Add a function to update a product.

updateProduct(id, prod) {
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; this.initDB().then((db) => {
&nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('UPDATE Product SET prodName = ?, prodDesc = ?, prodImage = ?, prodPrice = ? WHERE prodId = ?', [prod.prodName, prod.prodDesc, prod.prodImage, prod.prodPrice, id]).then(([tx, results]) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(results);
&nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; }).then((result) => {
&nbsp; &nbsp; &nbsp; &nbsp; this.closeDatabase(db);
&nbsp; &nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; });
&nbsp; }); &nbsp;
}

Add a function to delete a product.

deleteProduct(id) {
&nbsp; return new Promise((resolve) => {
&nbsp; &nbsp; this.initDB().then((db) => {
&nbsp; &nbsp; &nbsp; db.transaction((tx) => {
&nbsp; &nbsp; &nbsp; &nbsp; tx.executeSql('DELETE FROM Product WHERE prodId = ?', [id]).then(([tx, results]) => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; console.log(results);
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; resolve(results);
&nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; }).then((result) => {
&nbsp; &nbsp; &nbsp; &nbsp; this.closeDatabase(db);
&nbsp; &nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; });
&nbsp; }); &nbsp;
}

4. Show List of Product

To show or display the list of product, open and edit components/ProductScreen.js then replace all imports with these imports.

import React, { Component } from 'react';
import { StyleSheet, FlatList, ActivityIndicator, View, Text } from 'react-native';
import { ListItem, Button } from 'react-native-elements';
import Database from '../Database';

Instantiate the Database as a constant variable before the class name.

const db = new Database();

Next, replace navigationOptions with these.

static navigationOptions = ({ navigation }) => {
&nbsp; return {
&nbsp; &nbsp; title: 'Product List',
&nbsp; &nbsp; headerRight: (
&nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; buttonStyle={{ padding: 0, backgroundColor: 'transparent' }}
&nbsp; &nbsp; &nbsp; &nbsp; icon={{ name: 'add-circle', style: { marginRight: 0, fontSize: 28 } }}
&nbsp; &nbsp; &nbsp; &nbsp; onPress={() => {&nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; navigation.navigate('AddProduct', {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onNavigateBack: this.handleOnNavigateBack
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });&nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; }}
&nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; ),
&nbsp; };
};

Add a constructor function.

constructor() {
&nbsp; super();
&nbsp; this.state = {
&nbsp; &nbsp; isLoading: true,
&nbsp; &nbsp; products: [],
&nbsp; &nbsp; notFound: 'Products not found.\nPlease click (+) button to add it.'
&nbsp; };
}

Add a function to initialize the screen.

componentDidMount() {
&nbsp; this._subscribe = this.props.navigation.addListener('didFocus', () => {
&nbsp; &nbsp; this.getProducts();
&nbsp; });
}

Add a function to get the product list from Database class.

getProducts() {
&nbsp; let products = [];
&nbsp; db.listProduct().then((data) => {
&nbsp; &nbsp; products = data;
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; products,
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; }).catch((err) => {
&nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; this.setState = {
&nbsp; &nbsp; &nbsp; isLoading: false
&nbsp; &nbsp; }
&nbsp; })
}

Add a variable to iterate the listed product in the view.

keyExtractor = (item, index) => index.toString()

Add a function to render the List Item.

renderItem = ({ item }) => (
&nbsp; <ListItem
&nbsp; &nbsp; title={item.prodName}
&nbsp; &nbsp; leftAvatar={{
&nbsp; &nbsp; &nbsp; source: item.prodImage && { uri: item.prodImage },
&nbsp; &nbsp; &nbsp; title: item.prodName[0]
&nbsp; &nbsp; }}
&nbsp; &nbsp; onPress={() => {
&nbsp; &nbsp; &nbsp; this.props.navigation.navigate('ProductDetails', {
&nbsp; &nbsp; &nbsp; &nbsp; prodId: `${item.prodId}`,
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }}
&nbsp; &nbsp; chevron
&nbsp; &nbsp; bottomDivider
&nbsp; />
)

Add a function to render the rest of List view.

render() {
&nbsp; if(this.state.isLoading){
&nbsp; &nbsp; return(
&nbsp; &nbsp; &nbsp; <View style={styles.activity}>
&nbsp; &nbsp; &nbsp; &nbsp; <ActivityIndicator size="large" color="#0000ff"/>
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; )
&nbsp; }
&nbsp; if(this.state.products.length === 0){
&nbsp; &nbsp; return(
&nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; <Text style={styles.message}>{this.state.notFound}</Text>
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; )
&nbsp; }
&nbsp; return (
&nbsp; &nbsp; <FlatList
&nbsp; &nbsp; &nbsp; keyExtractor={this.keyExtractor}
&nbsp; &nbsp; &nbsp; data={this.state.products}
&nbsp; &nbsp; &nbsp; renderItem={this.renderItem}
&nbsp; &nbsp; />
&nbsp; );
}

Finally, add a stylesheet for the whole screen after the class bracket.

const styles = StyleSheet.create({
&nbsp; container: {
&nbsp; &nbsp;flex: 1,
&nbsp; &nbsp;paddingBottom: 22
&nbsp; },
&nbsp; item: {
&nbsp; &nbsp; padding: 10,
&nbsp; &nbsp; fontSize: 18,
&nbsp; &nbsp; height: 44,
&nbsp; },
&nbsp; activity: {
&nbsp; &nbsp; position: 'absolute',
&nbsp; &nbsp; left: 0,
&nbsp; &nbsp; right: 0,
&nbsp; &nbsp; top: 0,
&nbsp; &nbsp; bottom: 0,
&nbsp; &nbsp; alignItems: 'center',
&nbsp; &nbsp; justifyContent: 'center'
&nbsp; },
&nbsp; message: {
&nbsp; &nbsp; padding: 16,
&nbsp; &nbsp; fontSize: 18,
&nbsp; &nbsp; color: 'red'
&nbsp; }
});

5. Show Product Details and Delete Product

From the list of product view, you will see that list item has an action button to show the product details. Next, open and edit components/ProductDetailsScreen.js then replace the imports with these imports.

import React, { Component } from 'react';
import { ScrollView, StyleSheet, Image, ActivityIndicator, View, Text } from 'react-native';
import { Card, Button } from 'react-native-elements';
import Database from '../Database';

Instantiate the Database as a constant variable.

const db = new Database();

Add a function as the constructor.

constructor() {
&nbsp; super();
&nbsp; this.state = {
&nbsp; &nbsp; isLoading: true,
&nbsp; &nbsp; product: {},
&nbsp; &nbsp; id: '',
&nbsp; };
}

Add a function to initialize the screen.

componentDidMount() {
&nbsp; this._subscribe = this.props.navigation.addListener('didFocus', () => {
&nbsp; &nbsp; const { navigation } = this.props;
&nbsp; &nbsp; db.productById(navigation.getParam('prodId')).then((data) => {
&nbsp; &nbsp; &nbsp; console.log(data);
&nbsp; &nbsp; &nbsp; product = data;
&nbsp; &nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; &nbsp; product,
&nbsp; &nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; &nbsp; &nbsp; id: product.prodId
&nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; }).catch((err) => {
&nbsp; &nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; &nbsp; this.setState = {
&nbsp; &nbsp; &nbsp; &nbsp; isLoading: false
&nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; })
&nbsp; });
}

Add a function to delete a product data.

deleteProduct(id) {
&nbsp; const { navigation } = this.props;
&nbsp; this.setState({
&nbsp; &nbsp; isLoading: true
&nbsp; });
&nbsp; db.deleteProduct(id).then((result) => {
&nbsp; &nbsp; console.log(result);
&nbsp; &nbsp; this.props.navigation.goBack();
&nbsp; }).catch((err) => {
&nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; this.setState = {
&nbsp; &nbsp; &nbsp; isLoading: false
&nbsp; &nbsp; }
&nbsp; })
}

Add a function to render the whole Product Details view.

render() {
&nbsp; if(this.state.isLoading){
&nbsp; &nbsp; return(
&nbsp; &nbsp; &nbsp; <View style={styles.activity}>
&nbsp; &nbsp; &nbsp; &nbsp; <ActivityIndicator size="large" color="#0000ff" />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; )
&nbsp; }
&nbsp; return (
&nbsp; &nbsp; <ScrollView>
&nbsp; &nbsp; &nbsp; <Card style={styles.container}>
&nbsp; &nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Image
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; style={{width: 150, height: 150}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; source={{uri: this.state.product.prodImage}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Text style={{fontSize: 16}}>Product ID: {this.state.product.prodId}</Text>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Text style={{fontSize: 16}}>Product Name: {this.state.product.prodName}</Text>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Text style={{fontSize: 16}}>Product Desc: {this.state.product.prodDesc}</Text>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <View>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Text style={{fontSize: 16}}>Product Price: {this.state.product.prodPrice}</Text>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; <View style={styles.detailButton}>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; large
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; backgroundColor={'#CCCCCC'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; leftIcon={{name: 'edit'}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title='Edit'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; this.props.navigation.navigate('EditProduct', {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prodId: `${this.state.id}`,
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; });
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }} />
&nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; &nbsp; <View style={styles.detailButton}>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; large
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; backgroundColor={'#999999'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; color={'#FFFFFF'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; leftIcon={{name: 'delete'}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title='Delete'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.deleteProduct(this.state.id)} />
&nbsp; &nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; </Card>
&nbsp; &nbsp; </ScrollView>
&nbsp; );
}

Finally, add the stylesheet for this screen after the class bracket.

const styles = StyleSheet.create({
&nbsp; container: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; padding: 20
&nbsp; },
&nbsp; subContainer: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; paddingBottom: 20,
&nbsp; &nbsp; borderBottomWidth: 2,
&nbsp; &nbsp; borderBottomColor: '#CCCCCC',
&nbsp; },
&nbsp; activity: {
&nbsp; &nbsp; position: 'absolute',
&nbsp; &nbsp; left: 0,
&nbsp; &nbsp; right: 0,
&nbsp; &nbsp; top: 0,
&nbsp; &nbsp; bottom: 0,
&nbsp; &nbsp; alignItems: 'center',
&nbsp; &nbsp; justifyContent: 'center'
&nbsp; },
&nbsp; detailButton: {
&nbsp; &nbsp; marginTop: 10
&nbsp; }
})

6. Add Product

To add or save a new Product, open and edit the components/ProductAddScreen.js then replace all imports with these imports.

import React, { Component } from 'react';
import { StyleSheet, ScrollView, ActivityIndicator, View, TextInput } from 'react-native';
import { Button } from 'react-native-elements';
import Database from '../Database';

Instantiate the Database as a constant variable.

const db = new Database();

Add a constructor inside the class bracket after the navigationOptions.

constructor() {
&nbsp; super();
&nbsp; this.state = {
&nbsp; &nbsp; prodId: '',
&nbsp; &nbsp; prodName: '',
&nbsp; &nbsp; prodDesc: '',
&nbsp; &nbsp; prodImage: '',
&nbsp; &nbsp; prodPrice: '0',
&nbsp; &nbsp; isLoading: false,
&nbsp; };
}

Add a function to update the input text values.

updateTextInput = (text, field) => {
&nbsp; const state = this.state
&nbsp; state[field] = text;
&nbsp; this.setState(state);
}

Add a function to save a product to the SQLite table.

saveProduct() {
&nbsp; this.setState({
&nbsp; &nbsp; isLoading: true,
&nbsp; });
&nbsp; let data = {
&nbsp; &nbsp; prodId: this.state.prodId,
&nbsp; &nbsp; prodName: this.state.prodName,
&nbsp; &nbsp; prodDesc: this.state.prodDesc,
&nbsp; &nbsp; prodImage: this.state.prodImage,
&nbsp; &nbsp; prodPrice: this.state.prodPrice
&nbsp; }
&nbsp; db.addProduct(data).then((result) => {
&nbsp; &nbsp; console.log(result);
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; &nbsp; this.props.navigation.state.params.onNavigateBack;
&nbsp; &nbsp; this.props.navigation.goBack();
&nbsp; }).catch((err) => {
&nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; })
}

Add a function to render the whole add product view.

render() {
&nbsp; if(this.state.isLoading){
&nbsp; &nbsp; return(
&nbsp; &nbsp; &nbsp; <View style={styles.activity}>
&nbsp; &nbsp; &nbsp; &nbsp; <ActivityIndicator size="large" color="#0000ff"/>
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; )
&nbsp; }
&nbsp; return (
&nbsp; &nbsp; <ScrollView style={styles.container}>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product ID'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodId}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodId')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Name'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodName}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodName')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; multiline={true}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; numberOfLines={4}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Description'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodDesc}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodDesc')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Image'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodImage}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodImage')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Price'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodPrice}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; keyboardType='numeric'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodPrice')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.button}>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; large
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; leftIcon={{name: 'save'}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title='Save'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.saveProduct()} />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; </ScrollView>
&nbsp; );
}

Finally, add the style for the whole screen.

const styles = StyleSheet.create({
&nbsp; container: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; padding: 20
&nbsp; },
&nbsp; subContainer: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; marginBottom: 20,
&nbsp; &nbsp; padding: 5,
&nbsp; &nbsp; borderBottomWidth: 2,
&nbsp; &nbsp; borderBottomColor: '#CCCCCC',
&nbsp; },
&nbsp; activity: {
&nbsp; &nbsp; position: 'absolute',
&nbsp; &nbsp; left: 0,
&nbsp; &nbsp; right: 0,
&nbsp; &nbsp; top: 0,
&nbsp; &nbsp; bottom: 0,
&nbsp; &nbsp; alignItems: 'center',
&nbsp; &nbsp; justifyContent: 'center'
&nbsp; }
})

7. Edit Product

To edit a product, open and edit components/ProductEditScreen.js then replace all imports with these imports.

import React, { Component } from 'react';
import { StyleSheet, ScrollView, ActivityIndicator, View, TextInput } from 'react-native';
import { Button } from 'react-native-elements';
import Database from '../Database';

Instantiate the Database as a constant variable.

const db = new Database();

Add the constructor after the navigationOptions function.

constructor() {
&nbsp; super();
&nbsp; this.state = {
&nbsp; &nbsp; prodId: '',
&nbsp; &nbsp; prodName: '',
&nbsp; &nbsp; prodDesc: '',
&nbsp; &nbsp; prodImage: '',
&nbsp; &nbsp; prodPrice: '0',
&nbsp; &nbsp; isLoading: true,
&nbsp; };
}

Add a function to initialize the screen that will get product data.

componentDidMount() {
&nbsp; const { navigation } = this.props;
&nbsp; db.productById(navigation.getParam('prodId')).then((data) => {
&nbsp; &nbsp; console.log(data);
&nbsp; &nbsp; const product = data;
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; prodId: product.prodId,
&nbsp; &nbsp; &nbsp; prodName: product.prodName,
&nbsp; &nbsp; &nbsp; prodDesc: product.prodDesc,
&nbsp; &nbsp; &nbsp; prodImage: product.prodImage,
&nbsp; &nbsp; &nbsp; prodPrice: product.prodPrice,
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; }).catch((err) => {
&nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; this.setState = {
&nbsp; &nbsp; &nbsp; isLoading: false
&nbsp; &nbsp; }
&nbsp; })
}

Add a function to update the input text value.

updateTextInput = (text, field) => {
&nbsp; const state = this.state
&nbsp; state[field] = text;
&nbsp; this.setState(state);
}

Add a function to update the product data.

updateProduct() {
&nbsp; this.setState({
&nbsp; &nbsp; isLoading: true,
&nbsp; });
&nbsp; const { navigation } = this.props;
&nbsp; let data = {
&nbsp; &nbsp; prodId: this.state.prodId,
&nbsp; &nbsp; prodName: this.state.prodName,
&nbsp; &nbsp; prodDesc: this.state.prodDesc,
&nbsp; &nbsp; prodImage: this.state.prodImage,
&nbsp; &nbsp; prodPrice: this.state.prodPrice
&nbsp; }
&nbsp; db.updateProduct(data.prodId, data).then((result) => {
&nbsp; &nbsp; console.log(result);
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; &nbsp; this.props.navigation.state.params.onNavigateBack;
&nbsp; &nbsp; this.props.navigation.goBack();
&nbsp; }).catch((err) => {
&nbsp; &nbsp; console.log(err);
&nbsp; &nbsp; this.setState({
&nbsp; &nbsp; &nbsp; isLoading: false,
&nbsp; &nbsp; });
&nbsp; })
}

Add a function to render the whole Edit Product screen.

render() {
&nbsp; if(this.state.isLoading){
&nbsp; &nbsp; return(
&nbsp; &nbsp; &nbsp; <View style={styles.activity}>
&nbsp; &nbsp; &nbsp; &nbsp; <ActivityIndicator size="large" color="#0000ff"/>
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; )
&nbsp; }
&nbsp; return (
&nbsp; &nbsp; <ScrollView style={styles.container}>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product ID'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodId}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodId')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Name'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodName}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodName')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; multiline={true}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; numberOfLines={4}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Description'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodDesc}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodDesc')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Image'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodImage}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodImage')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.subContainer}>
&nbsp; &nbsp; &nbsp; &nbsp; <TextInput
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; placeholder={'Product Price'}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value={this.state.prodPrice}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; keyboardType='numeric'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onChangeText={(text) => this.updateTextInput(text, 'prodPrice')}
&nbsp; &nbsp; &nbsp; &nbsp; />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; &nbsp; <View style={styles.button}>
&nbsp; &nbsp; &nbsp; &nbsp; <Button
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; large
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; leftIcon={{name: 'save'}}
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title='Save'
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; onPress={() => this.updateProduct()} />
&nbsp; &nbsp; &nbsp; </View>
&nbsp; &nbsp; </ScrollView>
&nbsp; );
}

Finally, add the stylesheet after the class bracket.

const styles = StyleSheet.create({
&nbsp; container: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; padding: 20
&nbsp; },
&nbsp; subContainer: {
&nbsp; &nbsp; flex: 1,
&nbsp; &nbsp; marginBottom: 20,
&nbsp; &nbsp; padding: 5,
&nbsp; &nbsp; borderBottomWidth: 2,
&nbsp; &nbsp; borderBottomColor: '#CCCCCC',
&nbsp; },
&nbsp; activity: {
&nbsp; &nbsp; position: 'absolute',
&nbsp; &nbsp; left: 0,
&nbsp; &nbsp; right: 0,
&nbsp; &nbsp; top: 0,
&nbsp; &nbsp; bottom: 0,
&nbsp; &nbsp; alignItems: 'center',
&nbsp; &nbsp; justifyContent: 'center'
&nbsp; }
})

8. Run and Test React Native and SQLite Offline Mobile App

As we show you at the first step, run the React Native and SQLite app using this command.

react-native run-android
react-native run-ios

After the new terminal window open, just go to the project folder then run this command.

react-native start

Now, you will see the whole application in the Android/iOS Device.

That it’s, the React Native and SQLite Offline Mobile App. You can get the full source code from our GitHub.

The Difference Between iOS And Android App Development Using React Native

In this <a href="https://www.cmarix.com/the-difference-between-ios-and-android-app-development-using-react-native/?utm_source=SB" target="_blank">blog</a>, learn how the in-app features from design elements to testing tools, React Native development for iOS and Android mobile app platforms offer several key differences that developers need to know about.

In this blog, learn how the in-app features from design elements to testing tools, React Native development for iOS and Android mobile app platforms offer several key differences that developers need to know about.

Build an iOS App with React Native and Publish it to the App Store

Build an iOS App with React Native and Publish it to the App Store

Convert an Android React Native app to iOS and publish it in the Apple App Store.

Convert an Android React Native app to iOS and publish it in the Apple App Store.

Apple’s App Store is the holy grail for mobile developers. With React Native you can develop native apps for Android and iOS using a single code-base but getting things ready for publishing can be tricky, especially if you are starting with an originally Android-only application.

Here you’ll be starting with the code from a previous monster Okta blog post designing and publishing a calculator-like app on the Android Play store, which includes authentication via Okta.

For this post, you’ll first get the Android app to work well on iOS, as well as adding a splash screen and app icon. Then you’ll go through the signing process and publishing onto the App Store.

Start by cloning the repo and installing all the required libraries.

git clone https://github.com/oktadeveloper/okta-react-native-prime-components-example
cd okta-react-native-prime-components-example
npm install


From here you should be able to say react-native run-android to deploy to an emulator or attached Android phone. Everything should work fine.

Configure Authentication for Your React Native iOS App

Right now when you click Login you will be taken to an Okta login page. This is connected to an Okta account I used for development. You need to create your own account and configure this app to use it.

First, sign up for a free Okta developer account, or log in if you already have one. Then navigate to Applications > Add Application. Select Native and click Next. Choose a name and click Done. Note your Login redirect URI and the Client ID since you have to add them to your app.

Now in your App.js find where the config variable is defined (near the top) and change the pertinent values to that of your Okta app:

const config = {
  issuer: 'https://{yourOktaDomain}/oauth2/default',
  clientId: '{clientId}',
  redirectUrl: '{redirectUrl}',
  additionalParameters: {},
  scopes: ['openid', 'profile', 'email', 'offline_access']
};


Running Your React Native App on iOS Simulator

Start by running react-native run-ios from a Mac computer. An iOS simulator should appear and in the console, your project will compile.

NOTE: If you get an error Print: Entry, ":CFBundleIdentifier", Does Not Exist there are several issues on Github tracking this with various suggestions on fixing it. The simplest might just to open up ios/prime_components.xcodeproj in Xcode and build the project from there.

You should see an error 'AppAuth/AppAuth.h' file not found. You need to link the AppAuth library to iOS. The easiest is with Cocoapods. Put the following into ios/Podfile:

platform :ios, '11.0'

target 'prime_components' do
  pod 'AppAuth', '>= 0.94'
end


After having installed Cocoapods change into ios/ and run pod install. This will take a while. Now close Xcode and open ios/prime_components.xcworkspace (note: the workspace, not the project!) in Xcode. The pods should appear as a separate project. Select a device and the project should build and run just fine (just click the play button). You may have to change the bundle identifier if the one used in this tutorial is already taken.

At this point, the factorization should work but if you click Login it will crash because your AppDelegate class needs to conform to RNAppAuthAuthorizationFlowManager. Open AppDelegate.h and change it to the following:

#import <UIKit/UIKit.h>
#import "RNAppAuthAuthorizationFlowManager.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate, RNAppAuthAuthorizationFlowManager>

@property (nonatomic, weak) id<RNAppAuthAuthorizationFlowManagerDelegate>authorizationFlowManagerDelegate;
@property (nonatomic, strong) UIWindow *window;

@end


Now the login button should take you through the authorization process.

Adjust Styling in Your React Native iOS App

When I ran the app, the font was a bit large and the banner looked like it was showing the background behind the app. To fix these:

  • In components/Button.js change the font size to 25
  • In components/Header.js change the font size to 65
  • In components/Input.js change the flex to 1.5 and the font size to 60

The transparency issue in the header is from the iOS status bar showing. To hide this import StatusBar from react-native in App.js and add <StatusBar hidden /> at the top of the container:

return (
  <Container>
    <StatusBar hidden />


The app should look correct now.

Set the Icon and Display Name and Run on a Device

As in the previous post, you can use an app like Iconic to create an icon (though that one is for Android). Once you have an icon you can use an online service like MacAppIcon to get all the sizes you need. Then in Xcode open the prime_components project and click on Images.xcassets. You will see all the icons you need to fill it - simply drag them the correct sizes from Finder.

You will also want to change the display name of your project to fix the app name on your device. This is in the Identity section of the project settings.

Make sure you have set up the signing team and also that the Build Active Architectures Only is set to Yes for both debug and release, for both projects - This can fix a lot of integration problems with the AppAuth library.

Once done, you should be able to deploy to a device and see a proper icon and name for your app.

Create a Splash Screen for Your React Native iOS App

iOS apps have splash screens while they load. React Native creates a basic LaunchScreen.dib image which is just a white screen with the app’s name.

The easiest way to change this is by using the React Native Toolbox.

  • In components/Button.js change the font size to 25
  • In components/Header.js change the font size to 65
  • In components/Input.js change the flex to 1.5 and the font size to 60

For example:

A good image manipulation program to use is GIMP.

Next, install the toolbox as well as ImageMagick:

npm install -g [email protected] [email protected]
brew install imagemagick


Now place your image inside of your project, close the workspace inside of XCode and run the following command:

yo rn-toolbox:assets --splash image.png --ios


Make sure to specify the correct project name! (In this case it is prime_components and not prime-components). The images should be generated and your project updated. Uninstall your app from the simulator/device and re-deploy from Xcode and you should see the new splash when loading the app.

Submit Your React Native App to the iOS Store

What follows are instructions on submitting your app to the App Store but since the Prime Components app already exists this is for those who have another app they’d like to submit. In that case, follow the instructions from the previous blog post (linked above) on how to design and build your own app before continuing here.

Review Guidelines

Before you begin it’s worth reading through Apple’s App Store Review Guidelines. In plain English, it explains what you need to make sure your app is ready (and why the app might be rejected during review). Things like safety and performance are covered, as well as business practices like advertising. A lot of it is very sensible.

App Store Connect

To get started login to App Store Connect and accept the terms and conditions. Then click on the My Apps icon.

Click on the plus sign and select New App. Fill in the required values. Here the Bundle ID is the bundle identifier you set in your project settings. It’s important this is a unique value - good practice is to start with a website you own like com.myblog.my_app. You can’t change this once you’ve submitted a build.

Once everything is filled in you will get to the app management page with three tabs for the App Store section: App Information, Pricing and Availability, and the iOS submission page.

Fill out everything as best you can. Any missing information will come out when you try to submit your app for review. Set the pricing to free, and the availability to all territories. Select two categories for your app in App Information. This is for people who are browsing for new apps.

Because you are not charging for your app and there is no advertising a lot of this process will go smoothly.

Build an Archive

iOS apps are distributed with archives. To build the archive, make sure the RnAppAuth is added to the target dependencies in the Build Phases of the prime_components project. Then go to Product and select Archive. This will rebuild and archive everything into one file.

Once done, the Organizer window should pop-up (which you can find in the Window menu):

From here you can validate your app. Click on Distribute to upload it to App Store Connect. Once that is done you should see the build in the submission page.

Screenshots

You need to add a few screenshots for your app. To do this simply go to the simulator menu - there is a screenshot option there. You might like to use a service like MockUPhone to give your screenshots a phone border.

Then you need to resize them in an app like Gimp. Your screenshots need to be the right size.

Once you’re finished, under the Prepare for Submission page select iPhone 5.5” Display (this is the only one you need to fill out), upload the screenshots you have.

Privacy Policy

Since October 2018 all apps in the App Store need a privacy policy, specified as a URL. Basically, you need to explain what data you collect and what you do with it. In this case, no data collected at all but you need to specify that and host a write-up for it on a website. There are several examples of what a privacy policy in this situation might look like such as this one.

Submission

Once all looks ready, click on the Submit for Review button in the preparation page. Here you will be asked to give your app a rating (you’ll be asked several questions about the app’s content). Make sure you’ve filled out the information of where reviewers will be able to contact you.

Once through, you should hear back within two days.