React Native CLI Android installation error

Issue

I am new to react native, I was trying to follow an example on how to launch react native app with react native CLI but I keep getting this error in my CMD.

C:\React Native Workspace\RN-CLI\FirstCli>npx react-native run-android
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 863 file(s) to forward-jetify. Using 12 workers...
info Starting JS server...
'adb' is not recognized as an internal or external command,
operable program or batch file.
info Launching emulator...
error Failed to launch emulator. Reason: No emulators found as an output of `emulator -list-avds`.
warn Please launch an emulator manually or connect a device. Otherwise app may fail to launch.
info Installing the app...
Starting a Gradle Daemon (subsequent builds will be faster)

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'.
> SDK location not found. Define location with an ANDROID_SDK_ROOT environment variable or by setting the sdk.dir path in your project's local properties file at 'C:\React Native Workspace\RN-CLI\FirstCli\android\local.properties'.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 10s

error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup.
Error: Command failed: gradlew.bat app:installDebug -PreactNativeDevServerPort=8081

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'.
> SDK location not found. Define location with an ANDROID_SDK_ROOT environment variable or by setting the sdk.dir path in your project's local properties file at 'C:\React Native Workspace\RN-CLI\FirstCli\android\local.properties'.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 10s

    at makeError (C:\React Native Workspace\RN-CLI\FirstCli\node_modules\execa\index.js:174:9)
    at C:\React Native Workspace\RN-CLI\FirstCli\node_modules\execa\index.js:278:16
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async runOnAllDevices (C:\React Native Workspace\RN-CLI\FirstCli\node_modules\@react-native-community\cli-platform-android\build\commands\runAndroid\runOnAllDevices.js:109:5)
    at async Command.handleAction (C:\React Native Workspace\RN-CLI\FirstCli\node_modules\@react-native-community\cli\build\index.js:192:9)
info Run CLI with --verbose flag for more details.

I need help with resolving these issues.

Solution

Assuming that you already have the Android SDK installed, you need to create a file named local.properties at the root of you Android project your-react-native-project-android/ and you should also add it to .gitignore if you are using git.

The file must indicate the path of the SDK on your computer, for macOS for example

local.properties

## This file must *NOT* be checked into Version Control Systems,
# as it contains information specific to your local configuration.
#
# Location of the SDK. This is only used by Gradle.
# For customization when using a Version Control System, please read the
# header note.
#Tue Oct 26 14:02:40 CEST 2021
sdk.dir=/Users/username/Library/Android/sdk

If you never installed the SDK, you need to start here

Answered By - yemd