Dự án KMP đầu tiên

MyFirstKmpApp/
├── composeApp/                 # Module chứa code UI
│   ├── src/
│   │   ├── commonMain/         # Code chung cho tất cả platforms
│   │   │   └── kotlin/
│   │   │       └── App.kt      # UI chung (Compose Multiplatform)
│   │   ├── androidMain/        # Code riêng cho Android
│   │   └── iosMain/            # Code riêng cho iOS
│   └── build.gradle.kts
├── shared/                     # Module shared logic (optional)
│   └── src/
│       ├── commonMain/         # Business logic chung
│       ├── androidMain/        # Logic riêng Android
│       └── iosMain/            # Logic riêng iOS
├── iosApp/                     # Xcode project cho iOS
│   └── iosApp.xcodeproj
└── build.gradle.kts            # Root Gradle config

@Composable
fun App() {
    MaterialTheme {
        var showContent by remember { mutableStateOf(false) }
        
        Column(
            modifier = Modifier.fillMaxSize(),
            horizontalAlignment = Alignment.CenterHorizontally,
            verticalArrangement = Arrangement.Center
        ) {
            Button(onClick = { showContent = !showContent }) {
                Text("Click me!")
            }
            
            AnimatedVisibility(showContent) {
                val greeting = remember { Greeting().greet() }
                Column(
                    horizontalAlignment = Alignment.CenterHorizontally
                ) {
                    Image(
                        painterResource(Res.drawable.compose_multiplatform),
                        contentDescription = null
                    )
                    Text("Compose: $greeting")
                }
            }
        }
    }
}

class Greeting {
    private val platform = getPlatform()
 
    fun greet(): String {
        return "Hello, ${platform.name}!"
    }
}

interface Platform {
    val name: String
}
 
expect fun getPlatform(): Platform

class AndroidPlatform : Platform {
    override val name: String = "Android ${android.os.Build.VERSION.SDK_INT}"
}
 
actual fun getPlatform(): Platform = AndroidPlatform()

import platform.UIKit.UIDevice
 
class IOSPlatform: Platform {
    override val name: String = UIDevice.currentDevice.systemName() + " " + 
                                 UIDevice.currentDevice.systemVersion
}
 
actual fun getPlatform(): Platform = IOSPlatform()

# Mở Simulator từ command line
open -a Simulator

fun greet(): String {
    return "Xin chào từ ${platform.name}!"
}

Tạo file local.properties ở root project với nội dung:
sdk.dir=/Users/yourname/Library/Android/sdk

# Xóa cache và thử lại
./gradlew clean
./gradlew --refresh-dependencies

sudo gem install cocoapods
cd iosApp
pod install