Could not connect to React Native development server on Android

Question

When I run react-native run-android, it gives me the following error:

Could not connect to development server

Answer 1

This is applicable to Android 9.0+ according to the Network Security Configuration. Well, so after trying all possible solutions I found on the web, I decided to investigate the native Android logcat manually. Even after adding android:usesCleartextTraffic="true", I found this in the logcat:

06-25 02:32:34.561 32001 32001 E unknown:ReactNative: Caused by: java.net.UnknownServiceException: CLEARTEXT communication to 192.168.29.96 not permitted by network security policy

So, I tried to inspect my react-native app's source. I found that in debug variant, there is already a network-security-config which is defined by react-native guys, that conflicts with the main variant.

There's an easy solution to this. Go to /android/app/src/debug/res/xml/react_native_config.xml Add a new line with your own IP address in the like:

  
    localhost
    10.0.2.2
    10.0.3.2
    ***192.168.29.96***
  

As my computer's local IP (check from ifconfig for linux) is 192.168.29.96, I added the above line in ***

Then, you need to clean and rebuild for Android!

cd /android
./gradlew clean
cd 
react-native run-android

I hope this works for you.