RxBroadcastReceiver

RxBroadcastReceiver.kt

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.util.Log
import io.reactivex.Observable
import io.reactivex.ObservableEmitter
import io.reactivex.subjects.PublishSubject


/**
 * @author Nibeaudeau Timothy <timothy.nibeaudeau@gmail.com>
 * @version 0.1
 * on 17/11/2018 for rxjava-sample with IntelliJ IDEA.
 */
/**
 * Helper class to store the context and the result intent
 * @param context the context where to [Context.registerReceiver] and [Context.unregisterReceiver] the [BroadcastReceiver]
 */
class IntentWithContext(val context: Context, val intent: Intent)


/**
 * Given an [filter] and a [context] create an [Observable] to listen broadcast which match the filter
 *
 * It will [Context.registerReceiver] to the [context] at the subscription to the observable and will
 * [Context.unregisterReceiver] when [Observable.doOnComplete] or [Observable.doOnDispose] are call to avoid leaking [context]
 *
 * @param context the context where to [Context.registerReceiver] and [Context.unregisterReceiver] the [BroadcastReceiver]
 * @param filter the IntentFilter to filter the broadcast
 */
fun Context.fromBroadcast(filter: IntentFilter): Observable<IntentWithContext> {
    var receiver: BroadcastReceiver? = null
    var isRegistered = false
    return PublishSubject.create { emitter: ObservableEmitter<IntentWithContext> ->
        receiver = object : BroadcastReceiver() {
            override fun onReceive(context: Context, intent: Intent) {
                emitter.onNext(IntentWithContext(context, intent))
            }
        }
        Log.i(TAG, "register")
        registerReceiver(receiver, filter)
        isRegistered = true
    }.doOnComplete {
        Log.i(TAG, "complete")
        if (receiver != null && isRegistered) {
            Log.i(TAG, "unregister")
            unregisterReceiver(receiver)
            isRegistered = false
        }
    }.doOnDispose {
        Log.i(TAG, "dispose")
        if (receiver != null && isRegistered) {
            Log.i(TAG, "unregister")
            unregisterReceiver(receiver)
            isRegistered = false
        }
    }
}