diff --git a/android/build.gradle b/android/build.gradle
index 849e79a..e8df4bf 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -11,13 +11,22 @@ buildscript {
 
 apply plugin: 'com.android.library'
 
+def safeExtGet(prop, fallback) {
+    rootProject.ext.has(prop) ? rootProject.ext.get(prop) : fallback
+}
+
+def DEFAULT_COMPILE_SDK_VERSION = 26
+def DEFAULT_BUILD_TOOLS_VERSION = "26.0.3"
+def DEFAULT_MIN_SDK_VERSION = 16
+def DEFAULT_TARGET_SDK_VERSION = 22
+
 android {
-    compileSdkVersion 26
-    buildToolsVersion "26.0.3"
+    compileSdkVersion safeExtGet('compileSdkVersion', DEFAULT_COMPILE_SDK_VERSION)
+    buildToolsVersion safeExtGet('buildToolsVersion', DEFAULT_BUILD_TOOLS_VERSION)
 
     defaultConfig {
-        minSdkVersion 16
-        targetSdkVersion 22
+        minSdkVersion safeExtGet('minSdkVersion', DEFAULT_MIN_SDK_VERSION)
+        targetSdkVersion safeExtGet('targetSdkVersion', DEFAULT_TARGET_SDK_VERSION)
         versionCode 1
         versionName "1.0"
     }