How to secure your android app using android code obfuscation
A common android obfuscation tool that comes with Android Studio is ProGuard. Its free and simple to use. No code is needed on the developer’s part as the output is obfuscated during the build process. Basically this tool is able to do simple obfuscation such as name mangling – changing of package, method and variable names. There are limits to what it can obfuscate though, such as being unable to obfuscate third-party library references as it will very likely break that functionality if it does so.
There are also other obfuscation tools, some that are commercial also. Just google around and you can find others that suits you (if ProGuard doesn’t)
Note : ProGuard is turned off by default.