now should fix android

android/build.gradle

@@ -1,12 +1,12 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 25
-    buildToolsVersion "25.0.2"
+    compileSdkVersion 26
+    buildToolsVersion "26.0.1"
 
     defaultConfig {
         minSdkVersion 16
-        targetSdkVersion 25
+        targetSdkVersion 26
         versionCode 1
         versionName "1.0"
         ndk {
@@ -19,6 +19,4 @@ dependencies {
     //noinspection GradleDynamicVersion
     provided 'com.facebook.react:react-native:+'
     compile "com.tonyodev.fetch2:fetch2:2.0.0-RC12"
-}
-
-  
+}