Equivalent of console.log on Android

Question

I am developing using React Native CLI as I need some Native Libraries in Android and iOS. Because of this I needed to use react-native link packagename

I then find out that the exposed methods for the Native Module in that package is not enough and I need to add some methods in the Native Module in Java (Android). Because of this I need to be able to debug in Java while I'm running React Native. I have tried System.out.println and it does not work. How can I log some result or message in Java when it is being called in a React Native project????

Answer 1

On the native Android side, you need to use the Log class from android.util.Log for logging.

Then, use adb logcat and filter the output for the tag provided to the function used from the Log class.

For example, on native Android side:

Log.d("THIS IS MY TAG", "HELLO WORLD")

Then in a terminal (assuming you have adb installed):

adb logcat -s "THIS IS MY TAG"

EDIT

Remember to add import android.util.Log at the top of the file that uses Log.d or anything else from the Log class.

EDIT #2

Also, you will need to run a full rebuild of your React Native project so that the modified native files are updated.

You can do this by running the following command: react-native run-android