Kotlin SDK usage example (#45)

* Kotlin SDK Android Example was added

* Readme file was added

* Update Readme.md

* Update Readme.md

* Unnecessary file was removed

kotlin-sdk-android-example/.gitignore

@@ -0,0 +1,15 @@
+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

kotlin-sdk-android-example/Readme.md

@@ -0,0 +1,10 @@
+# Kotlin SDK Android Example
+
+This is an Android app that uses Kotlin GrowthBook SDK
+
+# Overview
+
+If you have no Android Studio to build the application you can watch the app flow in [recorded video on YouTube Shorts](https://youtube.com/shorts/j1roM81QWc4?feature=share).
+
+
+![](./screenshots/Screenshot.png)

kotlin-sdk-android-example/app/.gitignore

@@ -0,0 +1 @@
+/build

kotlin-sdk-android-example/app/build.gradle

@@ -0,0 +1,56 @@
+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+    id 'org.jetbrains.kotlin.plugin.serialization'
+}
+
+android {
+    namespace 'com.example.growthbookdemoapp'
+    compileSdk 34
+
+    defaultConfig {
+        applicationId "com.example.growthbookdemoapp"
+        minSdk 26
+        targetSdk 34
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+    }
+
+    buildTypes {
+
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+            signingConfig signingConfigs.debug
+        }
+        debug {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+}
+
+
+dependencies {
+    implementation 'androidx.core:core-ktx:1.10.1'
+    implementation 'androidx.appcompat:appcompat:1.6.1'
+    implementation 'com.google.android.material:material:1.6.0'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
+
+    String ktorVersion = '2.1.1'
+    implementation("io.ktor:ktor-client-core:$ktorVersion")
+
+    implementation 'io.growthbook.sdk:GrowthBook:1.1.36'
+}

kotlin-sdk-android-example/app/proguard-rules.pro

@@ -0,0 +1,30 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
+
+#-dontobfuscate
+
+-keep class kotlinx.serialization.json.** { *; }
+
+#-keep class ** { *; }
+
+
+

kotlin-sdk-android-example/app/src/main/AndroidManifest.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.GrowthBookDemoApp"
+        tools:targetApi="31" >
+
+        <activity
+            android:name="com.example.growthbookdemoapp.MainActivity"
+            android:exported="true">
+
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

kotlin-sdk-android-example/app/src/main/java/com/example/growthbookdemoapp/MainActivity.kt

@@ -0,0 +1,68 @@
+package com.example.growthbookdemoapp
+
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+import androidx.appcompat.app.AppCompatActivity
+import com.sdk.growthbook.GBSDKBuilder
+import com.sdk.growthbook.GrowthBookSDK
+import com.sdk.growthbook.SDKBuilder
+import kotlinx.coroutines.DelicateCoroutinesApi
+
+class MainActivity: AppCompatActivity() {
+
+    private var growthBookSDK: GrowthBookSDK? = null
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.layout)
+
+        findViewById<Button>(R.id.btn_initialize).setOnClickListener {
+            onInitializeBtnClick()
+        }
+
+        findViewById<Button>(R.id.button).isEnabled = false
+        findViewById<Button>(R.id.button).setOnClickListener {
+            onBtnClick()
+        }
+    }
+
+    @OptIn(DelicateCoroutinesApi::class)
+    private fun onInitializeBtnClick() {
+        // User attributes for targeting and assigning users to experiment variations
+        val attrs = HashMap<String, Any>()
+        attrs["appBuildNumber"] = 3432
+
+        val sdkBuilder: SDKBuilder = GBSDKBuilder(
+            // Fetch and cache feature definitions from GrowthBook API
+            // If self-hosting, we recommend using a CDN in production
+            apiKey = "sdk-3e06aog6O1Mp6Ir",
+            hostURL = "https://cdn.growthbook.io/",
+            attributes = attrs,
+            trackingCallback = { gbExperiment, gbExperimentResult ->
+                // TODO: track in your analytics system
+                print("Viewed Experiment")
+                print("Experiment Id: " + gbExperiment.key)
+                print("Variation Id: " + gbExperimentResult.variationId)
+            },
+            // Provide the encryption key of type String if you intend to use data encryption,
+            // otherwise you can pass null
+            encryptionKey = null
+        )
+
+        growthBookSDK = sdkBuilder.initialize()
+        findViewById<TextView>(R.id.textView).text = getString(R.string.check_if_feature_enabled)
+        findViewById<Button>(R.id.button).isEnabled = true
+    }
+
+    private fun onBtnClick() {
+        val gb = growthBookSDK
+        val theText = when {
+            gb == null -> "sdk is null"
+            gb.feature("user576-feature").on -> "Feature is ON!"
+            else -> "Feature is OFF"
+        }
+
+        findViewById<TextView>(R.id.textView).text = theText
+    }
+}

kotlin-sdk-android-example/app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>