React-native (Signed) release apk keeps crashing in device

If possible use below in different terminal, issue will be showing on that terminal

adb logcat *:E

In my case the issue was the react-native-gesture-handler. When I checked logs using adb logcat it was showing the following error

Unsupported top level event type "onGestureHandlerStateChange" dispatched

solved it by doing import 'react-native-gesture-handler' in root App.js.

For more info check this

To those wanderers that face the same problem as I did, here's the solution:

i. Go to [ProjectName]/android/app/src/main

(If the directory doesn't contain index.android.bundle inside of assets folder, as not did mine. Then create a folder name assets. In case the files are present, delete the index.android.bundle file only.)

ii. After navigating to your root project directory in your Command Prompt type -

cd android

./gradlew clean

iii. Go back to your root directory in your Command Prompt and type -

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

And it's done. Don't forget to sign your newly build react-native app tho.