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

Kotlin: Here's a @Shiki's version in Kotlin with a little bit refactor in a fragment.

1. Register the observer in Fragment.

Fragment.kt

class MyFragment : Fragment() {

    private var mContext: Context? = null

    private val mMessageReceiver = object: BroadcastReceiver() {
        override fun onReceive(context: Context?, intent: Intent?) {
            //Do something here after you get the notification
            myViewModel.reloadData()
        }
    }

    override fun onAttach(context: Context) {
        super.onAttach(context)

        mContext = context
    }

    override fun onStart() {
        super.onStart()
        registerSomeUpdate()
    }

    override fun onDestroy() {
        LocalBroadcastManager.getInstance(mContext!!).unregisterReceiver(mMessageReceiver)
        super.onDestroy()
    }

    private fun registerSomeUpdate() {
        LocalBroadcastManager.getInstance(mContext!!).registerReceiver(mMessageReceiver, IntentFilter(Constant.NOTIFICATION_SOMETHING_HAPPEN))
    }

}

2. Post notification anywhere. Only you need the context.

   LocalBroadcastManager.getInstance(context).sendBroadcast(Intent(Constant.NOTIFICATION_SOMETHING_HAPPEN))```
   

PS:

1. you can add a Constant.kt like me for well organize the notifications. Constant.kt

object Constant {
    const val NOTIFICATION_SOMETHING_HAPPEN = "notification_something_happened_locally"
}

2. For the context in a fragment, you can use activity (sometimes null) or conext like what I used.