Simple event bus based on Android Architecture Component's LiveData. The code is initially based on Alfonz' LiveBus (https://github.com/petrnohejl/Alfonz/blob/dev/alfonz-arch/src/main/java/org/alfonz/arch/event/LiveBus.java) and was optimized for usage in Kotlin. This class needs Google's SingleLiveEvent (https://github.com/googlesamples/android…

LiveEventBus.kt

import android.arch.lifecycle.LifecycleOwner
import android.arch.lifecycle.Observer
import android.support.annotation.MainThread
import android.support.v4.util.ArrayMap

class LiveEventBus {
    private val events: MutableMap<Class<out Any>, SingleLiveEvent<out Any>> =
            ArrayMap<Class<out Any>, SingleLiveEvent<out Any>>()

    @MainThread
    @Suppress("UNCHECKED_CAST")
    fun <T : Any> observe(
            lifecycleOwner: LifecycleOwner,
            eventClass: Class<T>,
            eventObserver: (event: T) -> Unit) {
        events.getOrPut(eventClass) { SingleLiveEvent<T>() }
                .let { it as SingleLiveEvent<T> }
                .observe(lifecycleOwner, Observer<T> { event -> event?.let(eventObserver) })
    }

    @MainThread
    inline fun <reified T : Any> observe(
            lifecycleOwner: LifecycleOwner,
            noinline eventObserver: (event: T) -> Unit) =
            observe(lifecycleOwner, T::class.java, eventObserver)

    @MainThread
    fun <T : Any> removeObservers(lifecycleOwner: LifecycleOwner, eventClass: Class<T>) =
        events[eventClass]?.removeObservers(lifecycleOwner)

    @MainThread
    inline fun <reified T : Any> removeObservers(lifecycleOwner: LifecycleOwner) =
            removeObservers(lifecycleOwner, T::class.java)

    @Suppress("UNCHECKED_CAST")
    fun <T : Any> send(event: T) {
        events.getOrPut(event::class.java) { SingleLiveEvent<T>() }
                .let { it as SingleLiveEvent<T> }
                .value = event
    }
}