As zserge's comment suggested,
Timber is very nice, but if you already have an existing project - you may try github.com/zserge/log . It's a drop-in replacement for android.util.Log and has most of the the features that Timber has and even more.
his log library provides simple enable/disable log printing switch as below.
In addition, it only requires to change import lines, and nothing needs to change for Log.d(...); statement.
if (!BuildConfig.DEBUG)
Log.usePrinter(Log.ANDROID, false); // from now on Log.d etc do nothing and is likely to be optimized with JIT