fix(android_alarm_manager): Add Kotlin dependency and convert AlarmBroadcastReceiver class to Kotlin

packages/android_alarm_manager_plus/android/build.gradle

@@ -2,13 +2,15 @@ group 'dev.fluttercommunity.plus.androidalarmmanager'
 version '1.0-SNAPSHOT'
 
 buildscript {
+    ext.kotlin_version = '1.7.22'
     repositories {
         google()
         mavenCentral()
     }
 
     dependencies {
         classpath 'com.android.tools.build:gradle:8.1.2'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
 
@@ -20,6 +22,7 @@ rootProject.allprojects {
 }
 
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 33
@@ -31,6 +34,10 @@ android {
         targetCompatibility JavaVersion.VERSION_1_8
     }
 
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
     defaultConfig {
         minSdkVersion 19
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -42,6 +49,7 @@ android {
 }
 
 dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation 'androidx.appcompat:appcompat:1.6.1'
     api 'androidx.core:core:1.10.1'
 }

packages/android_alarm_manager_plus/android/src/main/kotlin/dev/fluttercommunity/plus/androidalarmmanager/AlarmBroadcastReceiver.kt

@@ -0,0 +1,29 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+package dev.fluttercommunity.plus.androidalarmmanager
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+
+class AlarmBroadcastReceiver : BroadcastReceiver() {
+  /**
+   * Invoked by the OS when a timer goes off.
+   *
+   * The associated timer was registered in [AlarmService].
+   *
+   * In Android, timer notifications require a [BroadcastReceiver] as the artifact that is
+   * notified when the timer goes off. As a result, this method is kept simple, immediately
+   * offloading any work to [AlarmService.enqueueAlarmProcessing].
+   *
+   * This method is the beginning of an execution path that will eventually execute a desired
+   * Dart callback function, as registered by the Dart side of the android_alarm_manager plugin.
+   * However, there may be asynchronous gaps between [onReceive] and the eventual invocation
+   * of the Dart callback because [AlarmService] may need to spin up a Flutter execution
+   * context before the callback can be invoked.
+   */
+  override fun onReceive(context: Context, intent: Intent) {
+    AlarmService.enqueueAlarmProcessing(context, intent)
+  }
+}