Dice Roller App - Kotlin

package com.example.diceroller

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.wrapContentSize
import androidx.compose.material3.Button
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.example.diceroller.ui.theme.DiceRollerTheme

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

            }

            }
        }
    }


@Preview(showBackground = true)
@Composable
fun DiceRollerApp() {
    DiceWithButtonAndImage(modifier = Modifier
        .fillMaxSize()
        .wrapContentSize(Alignment.Center))

}

@Composable
fun DiceWithButtonAndImage(modifier: Modifier = Modifier){
    var result by remember { mutableStateOf(1) }
    val imageResource = when (result) {
        1 -> R.drawable.dice_1
        2 -> R.drawable.dice_2
        3 -> R.drawable.dice_3
        4 -> R.drawable.dice_4
        5 -> R.drawable.dice_5
        else -> R.drawable.dice_6
    }
    Column (
        modifier = modifier,
        horizontalAlignment = Alignment.CenterHorizontally
            ){
        Image(
            painter = painterResource(imageResource),
            contentDescription = result.toString()
        )
        Spacer(modifier = Modifier.height(16.dp))
        Button(onClick = {result = (1..6).random()}) {
            Text(stringResource(R.string.roll))
        }
    }

}

컴포저블 2가지 -> DiceRollerApp, DiceWithButtonAndImage

DiceRollerApp

fun DiceRollerApp() {
    DiceWithButtonAndImage(modifier = Modifier
        .fillMaxSize()
        .wrapContentSize(Alignment.Center))

}

• DiceWithButtonAndImage 함수의 매개변수로 modifier 할당

• fillMaxSize(): content가 레이아웃을 최대로 활용하게함

• wrapContentSize(Alignment.Center: content가 레이아웃의 중간에 위치하게 함

DiceWithButtonAndImage

fun DiceWithButtonAndImage(modifier: Modifier = Modifier){
    var result by remember { mutableStateOf(1) }
    val imageResource = when (result) {
        1 -> R.drawable.dice_1
        2 -> R.drawable.dice_2
        3 -> R.drawable.dice_3
        4 -> R.drawable.dice_4
        5 -> R.drawable.dice_5
        else -> R.drawable.dice_6
    }
    Column (
        modifier = modifier,
        horizontalAlignment = Alignment.CenterHorizontally
            ){
        Image(
            painter = painterResource(imageResource),
            contentDescription = result.toString()
        )
        Spacer(modifier = Modifier.height(16.dp))
        Button(onClick = {result = (1..6).random()}) {
            Text(stringResource(R.string.roll))
        }
    }

}

• remember 컴포저블
  - 컴포저블은 기본적으로 stateless -> remember 컴포저블을 사용해서 result 변수가 값을 기억하도록 함
  - mutuableStateOf -> 변강 가능하다는 뜻
  

• imageResource
  - result 값에 따라서 주사위 그림을 다르게함
  
• Column을 이용해서 주사위와 roll 버튼을 수직으로 구성