diff --git a/app/build.gradle b/app/build.gradle
index 3985bd1..1d0bbec 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -4,7 +4,6 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
 
     defaultConfig {
         applicationId "com.potatoinc.instantappsample.app"
diff --git a/base/build.gradle b/base/build.gradle
index 2a47877..a75ea5d 100644
--- a/base/build.gradle
+++ b/base/build.gradle
@@ -4,7 +4,6 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
 
     baseFeature true
     defaultConfig {
diff --git a/base/src/main/java/com/example/android/instantappsample/base/Util.kt b/base/src/main/java/com/example/android/instantappsample/base/Util.kt
index 07aa496..7921140 100644
--- a/base/src/main/java/com/example/android/instantappsample/base/Util.kt
+++ b/base/src/main/java/com/example/android/instantappsample/base/Util.kt
@@ -1,8 +1,10 @@
 package com.example.android.instantappsample.base
 
 import android.app.Activity
+import android.content.Context
 import android.content.Intent
 import android.net.Uri
+import android.os.Build
 import com.google.android.gms.instantapps.InstantApps
 
 object Util {
@@ -18,4 +20,31 @@ object Util {
             )
         }
     }
+}
+
+fun Context.updateInstantAppCookie(byteArray: ByteArray): Boolean {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+        if (byteArray.size <= packageManager.instantAppCookieMaxBytes) {
+            packageManager.updateInstantAppCookie(byteArray)
+        } else {
+            return false
+        }
+    } else {
+        val packageManagerCompat = InstantApps.getPackageManagerCompat(this)
+        if (byteArray.size <= packageManagerCompat.instantAppCookieMaxSize) {
+            packageManagerCompat.setInstantAppCookie(byteArray)
+        } else {
+            return false
+        }
+    }
+
+    return true
+}
+
+fun Context.getInstantAppCookie(): ByteArray {
+    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+        packageManager.instantAppCookie
+    } else {
+        InstantApps.getPackageManagerCompat(this).instantAppCookie
+    }
 }
\ No newline at end of file
diff --git a/character-details/build.gradle b/character-details/build.gradle
index 2073a06..620df2f 100644
--- a/character-details/build.gradle
+++ b/character-details/build.gradle
@@ -4,7 +4,6 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
 
     defaultConfig {
         minSdkVersion rootProject.minSdkVersion
diff --git a/character-details/src/main/java/com/example/android/instantappsample/character_details/CharacterDetailsActivity.kt b/character-details/src/main/java/com/example/android/instantappsample/character_details/CharacterDetailsActivity.kt
index e24637c..412cef6 100644
--- a/character-details/src/main/java/com/example/android/instantappsample/character_details/CharacterDetailsActivity.kt
+++ b/character-details/src/main/java/com/example/android/instantappsample/character_details/CharacterDetailsActivity.kt
@@ -2,12 +2,11 @@ package com.example.android.instantappsample.character_details
 
 import android.arch.lifecycle.Observer
 import android.arch.lifecycle.ViewModelProviders
-import android.os.Build
 import android.os.Bundle
 import android.os.PersistableBundle
 import android.support.v7.app.AppCompatActivity
 import com.bumptech.glide.Glide
-import com.google.android.gms.instantapps.InstantApps
+import com.example.android.instantappsample.base.updateInstantAppCookie
 import kotlinx.android.synthetic.main.activity_character_details.*
 import timber.log.Timber
 import java.nio.charset.Charset
@@ -40,13 +39,7 @@ class CharacterDetailsActivity : AppCompatActivity() {
             }
         })
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            Timber.e("${packageManager.instantAppCookieMaxBytes}")
-            packageManager.updateInstantAppCookie(intent?.data.toString().toByteArray(Charset.defaultCharset()))
-        } else {
-            Timber.e("${InstantApps.getPackageManagerCompat(this).instantAppCookieMaxSize}")
-        }
-
+        updateInstantAppCookie(intent?.data.toString().toByteArray(Charset.defaultCharset()))
     }
 
 }
diff --git a/character-list/build.gradle b/character-list/build.gradle
index 8274a9b..29a8d5d 100644
--- a/character-list/build.gradle
+++ b/character-list/build.gradle
@@ -4,7 +4,6 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
 
     defaultConfig {
         minSdkVersion rootProject.minSdkVersion
diff --git a/character-list/src/main/java/com/example/android/instantappsample/character_list/CharacterListActivity.kt b/character-list/src/main/java/com/example/android/instantappsample/character_list/CharacterListActivity.kt
index 20fca1f..e11cad0 100644
--- a/character-list/src/main/java/com/example/android/instantappsample/character_list/CharacterListActivity.kt
+++ b/character-list/src/main/java/com/example/android/instantappsample/character_list/CharacterListActivity.kt
@@ -9,6 +9,7 @@ import android.os.Build
 import android.os.Bundle
 import android.support.v7.app.AppCompatActivity
 import android.view.View
+import com.example.android.instantappsample.base.getInstantAppCookie
 import com.google.android.gms.auth.api.credentials.*
 import com.google.android.gms.common.api.ApiException
 import com.google.android.gms.common.api.ResolvableApiException
@@ -88,6 +89,11 @@ public class CharacterListActivity : AppCompatActivity() {
                 }
     }
 
+    override fun onResume() {
+        super.onResume()
+        Timber.e(String(getInstantAppCookie(), Charset.defaultCharset()))
+    }
+
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         super.onActivityResult(requestCode, resultCode, data)
 
diff --git a/instantapp/build.gradle b/instantapp/build.gradle
index 15628c7..82b70ca 100644
--- a/instantapp/build.gradle
+++ b/instantapp/build.gradle
@@ -4,7 +4,6 @@ apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion rootProject.compileSdkVersion
-    buildToolsVersion rootProject.buildToolsVersion
 
     defaultConfig {
         minSdkVersion rootProject.minSdkVersion
diff --git a/proguard-rules.pro b/proguard-rules.pro
index 0daed52..62ad25c 100644
--- a/proguard-rules.pro
+++ b/proguard-rules.pro
@@ -98,6 +98,9 @@
 -keep, includedescriptorclasses class com.example.android.instantappsample.base.RestClient {
     public protected *;
 }
+-keep, includedescriptorclasses class com.example.android.instantappsample.base.UtilKt {
+    public protected *;
+}
 -keep, includedescriptorclasses class com.example.android.instantappsample.base.data.Character {
     public protected *;
 }