LifecycleLogger.kt

import android.arch.lifecycle.Lifecycle
import android.arch.lifecycle.LifecycleObserver
import android.arch.lifecycle.LifecycleOwner
import android.arch.lifecycle.OnLifecycleEvent
import com.nytimes.android.logger.Logger

class LifecycleLogger private constructor(private val className: String,
                                          private val lifecycle: Lifecycle,
                                          private val tag: String) : LifecycleObserver {

    companion object {
        fun attachTo(lifecycleOwner: LifecycleOwner, tag: String = "") {
            lifecycleOwner.lifecycle.addObserver(
                    LifecycleLogger(lifecycleOwner.javaClass.simpleName, lifecycleOwner.lifecycle, tag)
            )
        }
    }

    private fun logMethod(methodName: String) {
        Logger.d("[$className] $tag - $methodName")
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_ANY)
    fun onAnyEvent() {
        logMethod(lifecycle.currentState.name)
    }
}