MainActivity.kt

// Card

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

                Column() {
                    CardTest("1")
                    CardTest("2")
                    CardTest("3")
                    CardTest("4")
                }

            }
        }
    }
}

@Composable
fun CardTest(txt : String){

    Card(
        modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(10.dp),
        elevation = CardDefaults.cardElevation(
            defaultElevation = 3.dp
        ),
        shape = RoundedCornerShape(50.dp),
        border = BorderStroke(1.dp, Color.Black)
    ) {

        Box(modifier = Modifier
            .fillMaxSize()
            .background(Color.Blue),
            contentAlignment = Alignment.Center
        ) {

            Text(
                text = txt,
                fontSize = 30.sp
            )

        }

    }

}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    DefaultTheme {
        Column() {
            CardTest("1")
            CardTest("2")
            CardTest("3")
            CardTest("4")
        }
    }
}