Hello world Kotlin Jetpack Compose Example; Fixes:#3550

docs/modules/ROOT/pages/kotlinlib/android-examples.adoc

@@ -23,6 +23,14 @@ This example demonstrates how to create a basic "Hello World" Android applicatio
 using the Mill build tool. It outlines the minimum setup required to compile Kotlin code,
 package it into an APK, and run the app on an Android device.
 
+== Kotlin Android Jetpack Compose Application
+
+include::partial$example/kotlinlib/android/2-jetpack-compose-hello-world.adoc[]
+
+This example demonstrates how to create a basic "Hello World" Jetpack Compose Android application
+using the Mill build tool. It outlines the minimum setup required to compile Kotlin code, 
+Compiling Jetpack Compose Libraries, package it into an APK, and run the app on an Android device.
+
 == Understanding `AndroidSdkModule` and `AndroidAppKotlinModule`
 
 The two main modules you need to understand when building Android apps with Mill

example/javalib/android/1-hello-world/app/AndroidManifest.xml

@@ -1,7 +1,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.helloworld.app">
     <uses-sdk android:minSdkVersion="9"/>
     <uses-sdk android:targetSdkVersion="35"/>
-    <application android:label="Hello World" android:debuggable="true">
+    <application android:label="@string/app_name" android:theme="@android:style/Theme.Light.NoTitleBar" android:debuggable="true">
         <activity android:name=".MainActivity"
                 android:exported="true">
             <intent-filter>

example/javalib/android/1-hello-world/app/resources/values/colors.xml

@@ -0,0 +1,4 @@
+<resources>
+    <color name="white">#FFFFFF</color>
+    <color name="text_green">#34A853</color>
+</resources>

example/javalib/android/1-hello-world/app/resources/values/strings.xml

@@ -0,0 +1,4 @@
+<resources>
+    <string name="app_name">HelloWorldApp</string>
+    <string name="hello_world">Hello, World Java!</string>
+</resources>

example/javalib/android/1-hello-world/app/src/main/java/com/helloworld/app/MainActivity.java

@@ -2,11 +2,10 @@
 
 import android.app.Activity;
 import android.os.Bundle;
-import android.view.View;
+import android.view.Gravity;
 import android.widget.TextView;
 import android.view.ViewGroup.LayoutParams;
-import android.view.Gravity;
-
+import android.graphics.Color;
 
 public class MainActivity extends Activity {
     @Override
@@ -16,20 +15,26 @@ protected void onCreate(Bundle savedInstanceState) {
         // Create a new TextView
         TextView textView = new TextView(this);
 
-        // Set the text to "Hello, World!"
-        textView.setText("Hello, World!");
+        // Set the text to the string resource
+        textView.setText(getString(R.string.hello_world));
 
         // Set text size
         textView.setTextSize(32);
 
         // Center the text within the view
         textView.setGravity(Gravity.CENTER);
 
-        // Set layout parameters (width and height)
+        // Set the layout parameters (width and height)
         textView.setLayoutParams(new LayoutParams(
             LayoutParams.MATCH_PARENT,
             LayoutParams.MATCH_PARENT));
 
+        // Set the text color using a resource
+        textView.setTextColor(getResources().getColor(R.color.text_green));
+
+        // Set the background color using a resource
+        textView.setBackgroundColor(getResources().getColor(R.color.white));
+
         // Set the content view to display the TextView
         setContentView(textView);
     }

example/kotlinlib/android/1-hello-world/app/AndroidManifest.xml

@@ -1,7 +1,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.helloworld.app">
     <uses-sdk android:minSdkVersion="9"/>
     <uses-sdk android:targetSdkVersion="35"/>
-    <application android:label="Hello World" android:debuggable="true">
+    <application android:label="@string/app_name" android:theme="@android:style/Theme.Light.NoTitleBar" android:debuggable="true">
         <activity android:name=".MainActivity"
                 android:exported="true">
             <intent-filter>

example/kotlinlib/android/1-hello-world/app/resources/values/colors.xml

@@ -0,0 +1,4 @@
+<resources>
+    <color name="white">#FFFFFF</color>
+    <color name="text_green">#34A853</color>
+</resources>

example/kotlinlib/android/1-hello-world/app/resources/values/strings.xml

@@ -0,0 +1,4 @@
+<resources>
+    <string name="app_name">HelloWorldApp</string>
+    <string name="hello_world">Hello, World Kotlin!</string>
+</resources>

example/kotlinlib/android/1-hello-world/app/src/main/kotlin/com/helloworld/app/MainActivity.kt → example/kotlinlib/android/1-hello-world/app/src/main/java/com/helloworld/app/MainActivity.kt

@@ -2,9 +2,10 @@ package com.helloworld.app
 
 import android.app.Activity
 import android.os.Bundle
-import android.widget.TextView
 import android.view.Gravity
+import android.widget.TextView
 import android.view.ViewGroup.LayoutParams
+import android.graphics.Color
 
 class MainActivity : Activity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -13,8 +14,8 @@ class MainActivity : Activity() {
         // Create a new TextView
         val textView = TextView(this)
 
-        // Set the text to "Hello, World!"
-        textView.text = "Hello, World Kotlin!"
+        // Set the text to the string resource
+        textView.text = getString(R.string.hello_world)
 
         // Set text size
         textView.textSize = 32f
@@ -28,6 +29,12 @@ class MainActivity : Activity() {
             LayoutParams.MATCH_PARENT
         )
 
+        // Set the text color using a resource
+        textView.setTextColor(getColor(R.color.text_green)) // Using hex color code directly
+
+        // Set the background color using a resource
+        textView.setBackgroundColor(getColor(R.color.white)) // Using hex color code directly
+
         // Set the content view to display the TextView
         setContentView(textView)
     }

example/kotlinlib/android/1-hello-world/build.mill

@@ -22,7 +22,7 @@ object androidSdkModule0 extends AndroidSdkModule{
 // Actual android application
 object app extends AndroidAppKotlinModule {
 
-  def kotlinVersion = "2.0.0"
+  def kotlinVersion = "2.0.20"
   def androidSdkModule = mill.define.ModuleRef(androidSdkModule0)
 }
 

example/kotlinlib/android/2-jetpack-compose-hello-world/app/AndroidManifest.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.helloworld.app">
+    <uses-sdk android:minSdkVersion="21"/>
+    <uses-sdk android:targetSdkVersion="35"/>
+    <application android:label="@string/app_name" android:theme="@android:style/Theme.Light.NoTitleBar" android:debuggable="true">
+        <activity android:name=".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>

example/kotlinlib/android/2-jetpack-compose-hello-world/app/resources/values/colors.xml

@@ -0,0 +1,4 @@
+<resources>
+    <color name="white">#FFFFFF</color>
+    <color name="text_green">#34A853</color>
+</resources>

example/kotlinlib/android/2-jetpack-compose-hello-world/app/resources/values/strings.xml

@@ -0,0 +1,4 @@
+<resources>
+    <string name="app_name">HelloWorldApp</string>
+    <string name="hello_world">Hello, World!\nJetpack Compose!</string>
+</resources>

example/kotlinlib/android/2-jetpack-compose-hello-world/app/src/java/com/helloworld/app/MainActivity.kt

@@ -0,0 +1,41 @@
+package com.helloworld.app
+
+import android.app.Activity
+import android.graphics.Color
+import android.os.Bundle
+import android.view.Gravity
+import android.view.ViewGroup.LayoutParams
+import android.widget.LinearLayout
+import android.widget.TextView
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+
+class MainActivity : Activity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        val linearLayout = LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            gravity = Gravity.CENTER
+            setBackgroundColor(getColor(R.color.white)) // Use color from resources
+            layoutParams = LayoutParams(
+                LayoutParams.MATCH_PARENT,
+                LayoutParams.MATCH_PARENT
+            )
+        }
+
+        val textView = TextView(this).apply {
+            text = getString(R.string.hello_world)
+            textSize = 32f
+            setTextColor(getColor(R.color.text_green)) // Use color from resources
+            gravity = Gravity.CENTER
+            setPadding(16, 16, 16, 16) 
+        }
+
+        linearLayout.addView(textView)
+
+        setContentView(linearLayout)
+    }
+}

example/kotlinlib/android/2-jetpack-compose-hello-world/build.mill

@@ -0,0 +1,42 @@
+package build
+
+import mill._
+import kotlinlib._
+import coursier.maven.MavenRepository
+import mill.kotlinlib.android.AndroidAppKotlinModule
+import mill.javalib.android.AndroidSdkModule
+
+val maven_google = Seq(
+  MavenRepository("https://maven.google.com/"),
+  MavenRepository("https://repo1.maven.org/maven2")
+)
+
+object androidSdkModule0 extends AndroidSdkModule {
+  def buildToolsVersion = "35.0.0"
+}
+
+object app extends AndroidAppKotlinModule {
+  def kotlinVersion = "2.0.20"
+  def androidSdkModule = mill.define.ModuleRef(androidSdkModule0)
+
+  // If Dependencies are not provided but used in MainActivity then error will occur
+  override def mandatoryIvyDeps: T[Agg[Dep]] = Task {
+    super.mandatoryIvyDeps() ++ Agg(
+      // Jetpack Compose dependencies
+      ivy"androidx.compose.compiler:compiler:1.5.15",
+      ivy"androidx.activity:activity:1.8.2",
+      ivy"androidx.activity:activity-compose:1.8.2",
+      ivy"androidx.compose.runtime:runtime:1.3.1",
+      ivy"androidx.compose.material3:material3:1.0.1"
+    )
+  }
+
+  def repositoriesTask = T.task { super.repositoriesTask() ++ maven_google }
+}
+
+/** Usage
+
+> ./mill show app.androidApk
+".../out/app/androidApk.dest/app.apk"
+
+*/