Building Modern Android UIs with Kotlin

Kotlin + Jetpack Compose is the new standard for modern Android UI development. With Compose, XML layouts are gone—you write UIs entirely in Kotlin.

Jetpack Compose Basics

Compose uses @Composable functions to define UI elements:

@Composable
fun Greeting(name: String) {
    Text(text = "Hello $name")
}

Managing State

Compose encourages reactive programming:

var count by remember { mutableStateOf(0) }
Button(onClick = { count++ }) {
    Text("Clicked $count times")
}

UI Layouts

Compose uses Row, Column, Box, and other layout primitives.

Column(modifier = Modifier.padding(16.dp)) {
    Text("Welcome")
    Button(onClick = { /* ... */ }) {
        Text("Continue")
    }
}

Theming

Themes are managed via MaterialTheme:

MaterialTheme(
    colors = lightColors(primary = Color.Blue),
    typography = Typography(),
    shapes = Shapes()
) {
    // Content here
}

Navigation

Compose Navigation simplifies routing:

NavHost(navController, startDestination = "home") {
    composable("home") { HomeScreen() }
    composable("details/{id}") { backStack ->
        val id = backStack.arguments?.getString("id")
        DetailsScreen(id)
    }
}

Conclusion

Kotlin and Compose offer a cleaner, more powerful way to build Android UIs. Learn the core building blocks, and you'll be writing fluid, maintainable UIs in no time.