Update build.gradle

android/build.gradle

 def DEFAULT_TARGET_SDK_VERSION = 27
 def DEFAULT_COMPILE_SDK_VERSION = 27
 def DEFAULT_BUILD_TOOLS_VERSION = "28.0.3"
+def DEFAULT_SUPPORT_LIB_VERSION = "28.0.0"
 
 def getExtOrDefault(name, defaultValue) {
   return rootProject.ext.has(name) ? rootProject.ext.get(name) : defaultValue
 repositories {
   mavenCentral()
   jcenter()
+  google()
 
   def found = false
   def defaultDir = null
   }
 }
 
+def support_version = getExtOrDefault('supportLibVersion', DEFAULT_SUPPORT_LIB_VERSION)
+
 dependencies {
   //noinspection GradleDynamicVersion
   api 'com.facebook.react:react-native:+'
   implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+  implementation "com.android.support:appcompat-v7:$support_version"
 }