With the rapid growth of online websites, businesses, and the general ecosystem, it is crucial that website UIs load quickly on smartphones to encourage smartphone-based internet consumption. Facebook developed React Native from a need to generate UI elements efficiently, which formed the basis for creating the open-source web framework. Its native cross-platform capabilities allow usage for a wide range of platforms for application development, including Android, Web, Windows, UWP, tvOS, macOS, iOS, and AndroidTV. Microsoft also released a preview release in May 2020 that expanded the range of the React Native world, allowing desktop app development. React Native runs in the background of the destination device, and then communicates with the native platform via a batched asynchronous bridge. Its three main advantages are:
This article is about how to install and configure React Native CLI environment.
First, we will learn how to install the framework, then check whether it works well and finally develop an app.
This article guides first-time React Native users, junior developers, and developers with no experience with React Native. If curiosity nudged you to learn the framework due to the hype around React, then this is the guide you need.
These requirements ensure your tools run quickly and have enough storage for installation and development.
React Native requires macOS High Sierra (10.13) or higher to run efficiently.
HomeBrew is a package manager that helps you install and manage packages on Mac, and thus it will be essential to our installation process. You will install HomeBrew so that you can use it to install all the other tools necessary for React Native environment, including Nodejs, git, Watchman, and JDK.
The command verifies whether HomeBrew has been successfully installed and outputs the specific version installed as the following result shows:
homebrew 2.1.7 homebrew/homebrew-core (git revision f487; last commit 2020-05-26)
/usr/bin/ruby -e “$(curl –fsSL https://raw.githubusercontent.com/HomeBrew/install/master/install)”
If the software is well installed, the result will show the version and date as shown:
homebrew 2.1.7 homebrew/homebrew-core(git revision f487; last commit 2020-05-26)
brew install node
If the installation has occurred successfully, the Nodejs version will show up:
If the installation is successful, you will see the version as shown below:
Watchman monitors the files and folders utilized by the framework and triggers specific actions if the files are modified. It would be best if you had Watchman for React Native to monitor source codes and rebuild them once they are changed.
brew install watchman
if properly installed, the result will show the version as shown below:
npm install --g react-native-cli
If the installation is successful, you will see the version as shown:
react-native-cli:2.0.1 react-native:n/a - not inside a React Native Project
Xcode > Preferences > Locations
You should see the Command Line Tools settings showing the version of Xcode as:
Xcode 10.2.1 (10E1001)
Coacoapods manages dependencies in iOS development, and thus it is necessary to develop an app by react-native.
sudo gem install cocoapods
if installation is successful, you can see the version as shown below:
brew tap AdoptOpenJDK/openjdk brew cask install adoptopenjdk8
If you see the Java version as shown below, then Java has been successfully installed:
openjdk version "1.8.0_222" OpenJDK Runtime Environment (AdoptOpenJDK)(BUILD 1.8.0_222-b10) OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.222-b10, mixed mode)
If the installation is successful, the following result shows up:
Android Studio is also an essential tool for developing an Android app using react-native.
ANDROID STUDIO SDK CONFIGURATION
Select the Show Package Details option and select the following options:
ANDROID STUDIO ENVIRONMENT VARIABLE CONFIGURATION
You need to set environment variables to ensure the development environment fits your specifications. Ensure that the ANDROID_HOME environment variable connects to your existing Android SDK to avoid complications.
Open and include the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:
For .bash_profile users, use the following command:
The correct result if all variables are successfully configured is:
Android Debug Bridge Version 1.0.41 version 29.0.1-5644136 Installed as /Your Android SDK Directory Location/platform-tools/adb
1.You can also use git, which comes with Xcode. However, if its unavailable, run the code below:
brew install git
git is a substitute for the Android Studio development environment.
Sometimes you may need to modify the java code, in which case, your development speed will be affected. Gradle Daemon is a tool that manages these changes to speed up your development.
Expo CLI is a tool built to install and manage react-native frameworks. However, its unsuitable feature is that it has numerous native features, which makes building an app tedious and also makes the app size more extensive than it needs to be. Additionally, incorporating elements in an app that are not available in Expo CLI is difficult, making the tool unsuitable for developers. Despite that, Expo CLI has many useful native tools, unlike React Native CLI, such as geolocation, camera, the microphone that can come in handy for most application needs. Expo CLI is a much easier route than the react-native CLI route.
The installation process is as follows:
1.Install the Expo CLI command line utility using:
Npm install –g expo-cli
2.Run the command below to create your first project:
expo init my app
3. Browse to the directory with the following command in the terminal:
4. Finally, run the project
5. A development environment server will be started by these commands. Running the app requires installing the Expo client app to your device (iOS/Android) then connecting it to your computer. Android requires scanning the QR code on the terminal to authenticate the project, while iOS requires QR code scanning using the camera app. On the Android (emulator/real device), use the following command to initialize the app:
npm run android
6. While on the iOS emulator run:
npm run ios
Expo has docs that you can reference for solutions or even utilize the Expo Forums created for the Expo community to ask questions.
Expo is mostly best suited for beginners as it does not include the use of native code thus cannot be used to develop complex applications with custom components.
React Native project structure consists of a project directory with configuration files such as package.json, app.json, .watchman.json at the root; separate Android and iOS folders; a _tests_ folder with validation tests for the project; a nodes_module for housing smaller app modules; and an index.js file that maps the application and serves as the initialization point of the application. package.json specifies project dependencies and versions, while app.json contains the app name.
The npm (node package manager) manages the node_modules folder, which stores all the project library dependencies. You should avoid modifying the files present in the folder since alterations performed cannot be assured to be stable from updates/installs. Assets in the public folder are to be shared publicly. The src folder contains all development work by the developer, including components and source codes.
1. First, you need to lock the version you build with to ensure the app still works even after updates, using the following command:
npm config set save-exact=true
2. Create a native project through the command:
react-native init AwesomeProject cd AwesomeProject react-native run-ios
Your new app will run successfully in the emulator.
3. In iOS, execute the command below:
cd SampleApp #react-native run ios npm run ios
The react-native app will show up on the emulator.
4. On Android, run the following command:
cd SampleApp #react-native run-android npm run android
Your Android emulator will output:
Welcome to React
Hello World is a simple program for most development environments. Open index.ios.js for iOS or index.android.js for Android, then proceed to delete everything between the tags <View></View>. Write <Text>Hello World</Text> and execute the emulator.
The result will be Hello World on the screen.
Open and add the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:
#export ANDROID_HOME=$HOME/Library/Android/sdk export ANDROID_HOME=android SDK directory location/ Android/sdk export PATH=$PATH:$ANDROID_HOME/emulator export PATH=$PATH:ANDROID_HOME/tools export PATH=$PATH:$ANDROID_HOME/tools/bin export PATH=$PATH:$ANDROID_HOME/platform-tools
For .bash_profile users, use the following command:
Then proceed to verify the correction using the following code:
echo $ANDROID_HOME // default: /Users/<USERNAME>/Library/Android/sdk
Avdmanager list avd
Emulator –avd <NAME>
Wait for the device to boot up, then run your app in the emulator
Your app should run successfully.
Wrong Android emulator – you need to find the right emulator using the following code:
find - -name emulator –type f /Users/<USERNAME>/Library/Android/sdk/emulator // this /Users/<USERNAME>/Library/Android/sdk/tools/emulator // not this
Restart the terminal and verify the error is gone.
Avdmanager not found- write ~/.bash_profile, then add the following code afterwards:
PATH=$PATH:$ANDROID_HOME/tool s/bin export PATH
Quit and restart the terminal, then run the tools.
Sometimes you might need to uninstall and wipe off the whole react-native environment due to issues such as a broken development environment which can be caused by misusing commands or assigning storage to variables incorrectly.
To do so efficiently, use the uninstall command together with the -g flag, then include the scope if the package is scoped. A good example is as follows;
npm uninstall -g react-native-cli
npm uninstall <package_name>
for scoped package use
npm uninstall <@scope/package_name>
As our installations have a package.json file, you might need to remove a package from the dependencies in that file. Use the following commands to effect these changes:
npm uninstall --save <package_name>
or the following for a scoped package
npm uninstall --save <@scope/package_name>
You will also need to verify if the uninstallation is successful through the following commands on macOS:
This command ensures the node_modules do not contain a folder for the uninstalled files.
The guide presented has shown how to install React Native through various methods and why the tools stated are required, then showed examples of apps and finally the uninstallation procedure. Tooling and development in React Native are simple, and the learning curve is short, making it an ideal framework for web developers.
The growth of internet consumers, cross-platform development, and the whole of the internet ecosystem is an excellent catalyst for React Native to grow in popularity among developers. It offers them faster development speed while offering internet consumers speedier loading times and more beautiful website UIs.
As you have seen, React development is simple; hence it should convince you to get started and launch your own apps within a short period. Being a new but highly applicable language, React Native holds a lot of opportunities, career wise and development wise. There are also numerous React Native platforms on the internet that can help you solve challenges you might face in development. Keep coding and have fun!
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