Run react-native on android emulator

I had a similar problem, and after spending so much time and lots of searching about this issue the only trick worked for me:

1. Please Install the Required SDKs as shown in this figure

Configure Required SDKs

2. If You have already installed it, so you must have to update the following SDKs:
   • Android SDK Tool (update it to latest version)
   • Android SDK Platform-tools (update it to latest version)
   • Android SDK Build-tools (update it to latest version)
   • Android Support Repository under Extra folder (update it to latest version)
3. You Must have at least Installed the Same version Android API as the installed Android SDK Build-tools & Android SDK Platform-tools version as shown in the Configure Required SDKs figure above.

Note: Local Maven repository for Support Libraries which is listed as the SDK requirement in the official docs of React-native is now named as Android Support Repository in the SDK Manager .

React Native (On Mac OS Big SUR)

i was stuck here. But updating the environment settings for Android studio did the trick.

nano ~/.zshrc

and paste

export ANDROID_SDK_ROOT=$HOME/Library/Android/sdk
export ANDROID_HOME=$HOME/Library/Android/sdk
export PATH=$PATH:$ANDROID_HOME/emulator:$PATH
export PATH=$PATH:$ANDROID_HOME/tools:$PATH
export PATH=$PATH:$ANDROID_HOME/tools/bin:$PATH
export PATH=$PATH:$ANDROID_HOME/platform-tools:$PATH
export JAVA_HOME=$(/usr/libexec/java_home)

control + o to save then enter then control + x to exit

then do source ~/.zshrc to compile

kill the runnig terminals and run npx react-native run-android

On macOs I manage to fix this by adding:

export ANDROID_HOME=$HOME/Library/Android/sdk
export PATH=$PATH:$ANDROID_HOME/emulator
export PATH=$PATH:$ANDROID_HOME/tools
export PATH=$PATH:$ANDROID_HOME/tools/bin
export PATH=$PATH:$ANDROID_HOME/platform-tools

to ~/.zsh_profile file.

and than type to your terminal

source $HOME/.zsh_profile

The issue was caused by using iTerm2 shell so it's required to edit its own config instead of default $HOME/.bash_profile as described in the official documentation https://reactnative.dev/docs/environment-setup