feat(android): add kotlin and coroutines

Author: Krzysztof Borowy

android/build.gradle

@@ -2,19 +2,42 @@ def safeExtGet(prop, fallback) {
     rootProject.ext.has(prop) ? rootProject.ext.get(prop) : fallback
 }
 
+def useDedicatedExecutor = rootProject.hasProperty('AsyncStorage_dedicatedExecutor')
+        ? rootProject.properties['AsyncStorage_dedicatedExecutor']
+        : false
+
+
 buildscript {
-    // The Android Gradle plugin is only required when opening the android folder stand-alone.
-    // This avoids unnecessary downloads and potential conflicts when the library is included as a
-    // module dependency in an application project.
-    if (project == rootProject) {
-        repositories {
-            google()
+    def isRootProject = project == rootProject
+
+    ext.ktCoroutinesVersion = "1.3.8"
+
+    // kotlin version can be set by setting ext.kotlinVersion or having it in gradle.properties in root
+    ext.asyncStorageKtVersion = rootProject.ext.has('kotlinVersion')
+            ? rootProject.ext.get('kotlinVersion')
+            : properties['kotlinVersion']
+            ? properties['kotlinVersion']
+            : "1.3.72"
+
+    repositories {
+        if (isRootProject) {
             jcenter()
         }
-        dependencies {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$asyncStorageKtVersion"
+        if (isRootProject) {
+            // The Android Gradle plugin is only required when opening the android folder stand-alone.
+            // This avoids unnecessary downloads and potential conflicts when the library is included as a
+            // module dependency in an application project.
             classpath 'com.android.tools.build:gradle:3.5.0'
         }
     }
+
+
 }
 
 // AsyncStorage has default size of 6MB.
@@ -24,16 +47,12 @@ buildscript {
 long dbSizeInMB = 6L
 
 def newDbSize = rootProject.properties['AsyncStorage_db_size_in_MB']
-
-if( newDbSize != null && newDbSize.isLong()) {
+if (newDbSize != null && newDbSize.isLong()) {
     dbSizeInMB = newDbSize.toLong()
 }
 
-def useDedicatedExecutor = rootProject.hasProperty('AsyncStorage_dedicatedExecutor')
-        ? rootProject.properties['AsyncStorage_dedicatedExecutor']
-        : false
-
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion safeExtGet('compileSdkVersion', 28)
@@ -62,4 +81,6 @@ repositories {
 dependencies {
     //noinspection GradleDynamicVersion
     implementation 'com.facebook.react:react-native:+'  // From node_modules
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$asyncStorageKtVersion"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$ktCoroutinesVersion"
 }