A Lifecycle components aware BroadcastReceiver DSL (Kotlin)

BroadcastReceiver.kt

import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import androidx.lifecycle.Lifecycle.Event.ON_DESTROY
import androidx.lifecycle.Lifecycle.Event.ON_START
import androidx.lifecycle.LifecycleObserver
import androidx.lifecycle.LifecycleOwner
import androidx.lifecycle.OnLifecycleEvent
import android.content.BroadcastReceiver as StockReceiver

/** @author Aidan Follestad (@afollestad) */
class BroadcastReceiver<T>(
  context: T,
  constructor: Builder.() -> Unit
) : LifecycleObserver where T : Context, T : LifecycleOwner {

  private val appContext = context.applicationContext
  private val filter: IntentFilter
  private val instructions: List<Instructions>

  init {
    val builder = Builder()
    constructor(builder)
    filter = builder.filter()
    instructions = builder.instructions()

    context.lifecycle.addObserver(this)
  }

  private val broadcastReceiver = object : StockReceiver() {
    override fun onReceive(
      context: Context,
      intent: Intent
    ) {
      for (ins in instructions) {
        if (ins.matches(intent)) {
          ins.execution()
              .invoke(intent)
          break
        }
      }
    }
  }

  @OnLifecycleEvent(ON_START)
  fun start() {
    appContext.registerReceiver(broadcastReceiver, filter)
  }

  @OnLifecycleEvent(ON_DESTROY)
  fun stop() = appContext.unregisterReceiver(broadcastReceiver)
}

Builder.kt

import android.content.IntentFilter

/** @author Aidan Follestad (@afollestad) */
class Builder internal constructor() {

  private val filter = IntentFilter()
  private val instructions = mutableListOf<Instructions>()

  fun onAction(
    action: String,
    execution: Execution
  ) {
    filter.addAction(action)
    instructions.add(OnAction(action, execution))
  }

  fun onDataScheme(
    scheme: String,
    execution: Execution
  ) {
    filter.addDataScheme(scheme)
    instructions.add(OnDataScheme(scheme, execution))
  }

  fun onCategory(
    category: String,
    execution: Execution
  ) {
    filter.addCategory(category)
    instructions.add(OnCategory(category, execution))
  }

  internal fun filter() = filter

  internal fun instructions() = instructions
}

Instructions.kt

import android.content.Intent

typealias Execution = (Intent) -> Unit

/** @author Aidan Follestad (@afollestad) */
sealed class Instructions {

  abstract fun matches(intent: Intent): Boolean

  abstract fun execution(): Execution

  data class OnAction(
    val action: String,
    val execution: Execution
  ) : Instructions() {

    override fun matches(intent: Intent): Boolean {
      return intent.action == action
    }

    override fun execution() = execution
  }

  data class OnDataScheme(
    val scheme: String,
    val execution: Execution
  ) : Instructions() {
    override fun matches(intent: Intent): Boolean {
      return intent.data?.scheme == scheme
    }

    override fun execution() = execution
  }

  data class OnCategory(
    val category: String,
    val execution: Execution
  ) : Instructions() {
    override fun matches(intent: Intent): Boolean {
      return intent.hasCategory(category)
    }

    override fun execution() = execution
  }
}

UsageExample.kt

class MyActivity : AppCompatActivity() {
  
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    
    // Will automatically unregister itself when the Activity pauses, and register again when it resumes.
    BroadcastReceiver(this) {
      onAction("com.yourapp.helloworld.SOME_ACTION") {
        // Do something
      }
      onCategory("messages") {
        // Do something
      }
      onDataScheme("file://") {
        // Do something
      }
    }
  }
}

This... is wonderful. Thank you very much.