feat: add more gradle properties (#343)

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### next
 
+* Add more gradle configuration properties `compileSdkVersion`, `buildToolsVersion`, `targetSdkVersion`
+
 ### 0.20.0
 
 * Made the following methods compatible with UWP: (https://github.com/rebeccahughes/react-native-device-info/pull/345)

android/build.gradle

 apply plugin: 'com.android.library'
 
+def DEFAULT_COMPILE_SDK_VERSION             = 23
+def DEFAULT_BUILD_TOOLS_VERSION             = "25.0.2"
+def DEFAULT_TARGET_SDK_VERSION              = 22
+def DEFAULT_GOOGLE_PLAY_SERVICES_VERSION    = "+"
+
 android {
-    compileSdkVersion 23
-    buildToolsVersion "25.0.2"
+    compileSdkVersion project.hasProperty('compileSdkVersion') ? project.compileSdkVersion : DEFAULT_COMPILE_SDK_VERSION
+    buildToolsVersion project.hasProperty('buildToolsVersion') ? project.buildToolsVersion : DEFAULT_BUILD_TOOLS_VERSION
 
     defaultConfig {
         minSdkVersion 16
-        targetSdkVersion 22
+        targetSdkVersion project.hasProperty('targetSdkVersion') ? project.targetSdkVersion : DEFAULT_TARGET_SDK_VERSION
         versionCode 2
         versionName "1.1"
         ndk {
@@ -19,7 +24,7 @@ android {
 }
 
 dependencies {
-    def googlePlayServicesVersion = project.hasProperty('googlePlayServicesVersion') ? project.googlePlayServicesVersion : "+"
+    def googlePlayServicesVersion = project.hasProperty('googlePlayServicesVersion') ? project.googlePlayServicesVersion : DEFAULT_GOOGLE_PLAY_SERVICES_VERSION
 
     compile 'com.facebook.react:react-native:+'
     compile "com.google.android.gms:play-services-gcm:$googlePlayServicesVersion"