MainActivity.kt

// Surface
// 컨텐츠를 담아놓는 컨테이너
// Text / Button / Box / Surface

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            DefaultTheme {
                MySurface2()
            }
        }
    }
}

@Composable
fun MySurface1(){

    Surface(
        modifier = Modifier
            .fillMaxWidth()
            .padding(10.dp),
        color = Color.Red,
        shape = RoundedCornerShape(20.dp),
        shadowElevation = 20.dp
    ) {
        Button(
            onClick = {  },
            colors = ButtonDefaults.outlinedButtonColors(
                contentColor = Color.Green
            )
        ) {
            Text(text = "클릭해보세요")
        }
    }

}

@Composable
fun MySurface2(){

    Surface(
        modifier = Modifier.fillMaxSize(),
        color = Color.LightGray,
        border = BorderStroke(2.dp, Color.Red),
        contentColor = Color.Blue
    ) {

        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(20.dp),
            verticalArrangement = Arrangement.Center,
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            Surface(
                modifier = Modifier
                    .size(200.dp),
                color = Color.Red
            ) {
                Text(text = "This is Jetpack compose")
            }
            Spacer(modifier = Modifier.height(20.dp))
            Text(
                text = "This is Jetpack Compose Ex"
            )

        }

    }

}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    DefaultTheme {
        MySurface2()
    }
}