MainActivity.kt

// 모서리 둥글게하기

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyThemeTest4Theme {
                // A surface container using the 'background' color from the theme
                Surface(modifier = Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.background) {
                    RadiusTest2()
                }
            }
        }
    }
}

@Composable
fun RadiusTest1(){

    Column() {

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.extraLarge)
            .background(Color.Red)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.large)
            .background(Color.Red)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.medium)
            .background(Color.Red)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.small)
            .background(Color.Red)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.extraSmall)
            .background(Color.Red)
        ) {

        }

    }

}

@Composable
fun RadiusTest2(){

    Column() {

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.extraLarge)
            .background(Color.Blue)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.large)
            .background(Color.Blue)
        ) {

        }

        Box(modifier = Modifier
            .fillMaxWidth()
            .height(100.dp)
            .padding(20.dp)
            .clip(MaterialTheme.shapes.medium)
            .background(Color.Blue)
        ) {

        }

    }

}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    MyThemeTest4Theme {
        RadiusTest2()
    }
}

Theme.kt

MaterialTheme(
      colorScheme = colorScheme,
      typography = Typography,
      content = content,
	    shapes = shapes
)

Shapes.kt

val shapes = Shapes(
    extraLarge = RoundedCornerShape(100.dp),
    large = RoundedCornerShape(10.dp),
    medium = RoundedCornerShape(1.dp),
)