diff --git a/android/build.gradle b/android/build.gradle
index 12ceac3..c59c53a 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -1,5 +1,9 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
+def safeExtGet(prop, fallback) {
+    rootProject.ext.has(prop) ? rootProject.ext.get(prop) : fallback
+}
+
 buildscript {
     repositories {
         jcenter()
@@ -15,12 +19,12 @@ buildscript {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 23
-    buildToolsVersion "25.0.0"
+    compileSdkVersion safeExtGet('compileSdkVersion', 23)
+    buildToolsVersion safeExtGet('buildToolsVersion', "25.0.0")
 
     defaultConfig {
-        minSdkVersion 16
-        targetSdkVersion 22
+        minSdkVersion safeExtGet('minSdkVersion', 16)
+        targetSdkVersion safeExtGet('targetSdkVersion', 22)
         versionCode 1
     }
     lintOptions {