Android equivalent to NSNotificationCenter

Question

In the process of porting an iPhone application over to android, I am looking for the best way to communicate within the app. Intents seem to be the way to go, is this the b

Answer 1

I wrote a wrapper that can do this same job, equivalent to iOS using LiveData

Wrapper:

class ObserverNotify {
    private val liveData = MutableLiveData<Nothing>()


    fun postNotification() {
        GlobalScope.launch {
            withContext(Dispatchers.Main) {
                liveData.value = liveData.value
            }
        }
    }

    fun observeForever(observer: () -> Unit) {
        liveData.observeForever { observer() }
    }

    fun observe(owner: LifecycleOwner, observer: () -> Unit) {
        liveData.observe(owner) { observer()}
    }

}

class ObserverNotifyWithData<T> {
    private val liveData = MutableLiveData<T>()


    fun postNotification(data: T) {
        GlobalScope.launch {
            withContext(Dispatchers.Main) {
                liveData.value = data
            }
        }
    }

    fun observeForever(observer: (T) -> Unit) {
        liveData.observeForever { observer(it) }
    }

    fun observe(owner: LifecycleOwner, observer: (T) -> Unit) {
        liveData.observe(owner) { observer(it) }
    }

}

Declaring observer types:

object ObserverCenter {
    val moveMusicToBeTheNextOne: ObserverNotifyWithData<Music> by lazy { ObserverNotifyWithData() }
    val playNextMusic: ObserverNotify by lazy { ObserverNotify() }
    val newFCMTokenDidHandle: ObserverNotifyWithData<String?> by lazy { ObserverNotifyWithData() }
}

In the activity to observe:

ObserverCenter.newFCMTokenDidHandle.observe(this) {
    // Do stuff
}

To notify:

ObserverCenter.playNextMusic.postNotification()
ObserverCenter.newFCMTokenDidHandle.postNotification("MyData")

Answer 2

You could use this: http://developer.android.com/reference/android/content/BroadcastReceiver.html, which gives a similar behavior.

You can register receivers programmatically through Context.registerReceiver(BroadcastReceiver, IntentFilter) and it will capture intents sent through Context.sendBroadcast(Intent).

Note, though, that a receiver will not get notifications if its activity (context) has been paused.