Add com.android.support:appcompat-v7:25.3.1 to dependencies.

Set SDK version to latest stable with available sources.

android/build.gradle

@@ -11,12 +11,12 @@ buildscript {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion '26'
+    compileSdkVersion 25
+    buildToolsVersion '25.0.3'
 
     defaultConfig {
         minSdkVersion 16
-        targetSdkVersion 26
+        targetSdkVersion 25
         versionCode 1
         versionName "1.0"
     }
@@ -35,5 +35,7 @@ repositories {
 }
 
 dependencies {
+    compile "com.android.support:appcompat-v7:25.3.1"
+    //noinspection GradleDynamicVersion
     compile 'com.facebook.react:react-native:+'
 }