RxActivity

RxActivity.kt

/**
 * Observe the activity events!
 */
class RxActivityDelegate : RxActivity {

    private val relay = BehaviorRelay.create<ActivityLifecycleEvent>().toSerialized()

    fun onCreate() {
        relay.call(CREATE)
        log("onCreate")
    }

    fun onStart() {
        relay.call(START)
        log("onStart")
    }

    fun onResume() {
        relay.call(RESUME)
        log("onResume")
    }

    fun onStop() {
        relay.call(STOP)
        log("onStop")
    }

    fun onPause() {
        relay.call(PAUSE)
        log("onPause")
    }

    fun onDestroy() {
        relay.call(DESTROY)
        log("onDestroy")
    }

    override fun observe(): Observable<ActivityLifecycleEvent> {
        return relay.asObservable()
                .doOnNext { Timber.d("emitted ${it.name}") }
    }

    private fun log(lifecycleMethod: String) {
        Timber.d("$this: $lifecycleMethod")
    }
}

interface RxActivity {

    fun observe(): Observable<ActivityLifecycleEvent>
}

/**
 * Lifecycle event
 */
enum class ActivityLifecycleEvent(
        val isCreated: Boolean,
        val isStarted: Boolean,
        val isResumed: Boolean
) {
    CREATE(
            isCreated = true,
            isStarted = false,
            isResumed = false
    ),
    START(
            isCreated = true,
            isStarted = true,
            isResumed = false
    ),
    RESUME(
            isCreated = true,
            isStarted = true,
            isResumed = true
    ),
    PAUSE(
            isCreated = true,
            isStarted = true,
            isResumed = false
    ),
    STOP(
            isCreated = true,
            isStarted = false,
            isResumed = false
    ),
    DESTROY(
            isCreated = false,
            isStarted = false,
            isResumed = false
    );

    fun isDestroyed(): Boolean {
        return this == DESTROY
    }
}