MainActivity.kt

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            DefaultTheme {
                MyDiceApp()
            }
        }
    }
}

@Composable
fun MyDiceApp(){

    var diceNumber by remember {
        mutableStateOf(1)
    }

    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(Color.LightGray),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        
        Box(
            modifier = Modifier
                .size(300.dp)
                .border(3.dp, Color.Black)
                .background(Color.White)
                .padding(20.dp)
        ) {

        }

        Button(
            onClick = {
                // 1 - 6
                diceNumber = Random.nextInt(1,7)
            },
            modifier = Modifier
                .fillMaxWidth()
                .padding(50.dp)
                .height(50.dp),
            colors = ButtonDefaults.buttonColors(
                containerColor = Color.White
            )
        ) {
            Text(
                text = "주사위 굴리기",
                color = Color.Black,
                fontWeight = FontWeight.Bold,
                textAlign = TextAlign.Center,
                fontSize = 20.sp,
                modifier = Modifier.fillMaxWidth()
            )
        }

        Text(
            text = diceNumber.toString(),
            fontWeight = FontWeight.Bold,
            fontSize = 30.sp
        )

    }

}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    DefaultTheme {
        MyDiceApp()
    }
}