Unresolved reference

Native
1

I would like to fix ‘Unresolved reference: roll’ on line 73 in my code. I read the online reference for my function here but this didn’t help me. I tried coding ‘android.R.string.roll’, removing the ‘.roll’ and importing R.string but this didn’t work either.


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 androidx.compose.ui.unit.sp
import com.example.diceroller.ui.theme.DiceRollerTheme

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            DiceRollerTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    DiceRollerApp()
                }
            }
        }
    }
}

@Preview
@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())

        Button(
            onClick = { result = (1..6).random() },
        ) {
            Text(text = stringResource(R.string.roll), fontSize = 24.sp)
        }
    }
}
2

I’m not surprised that the compiler can’t find a roll; I can’t find it either!

I can’t see one in your code, and there isn’t one listed in the linked documentation for R.string. What do you expect it to refer to, and where would it be defined?

(The question refers to a ‘function’, but according to that documentation R.string is a class. And that class has no member functions; if it had a member roll, that would have to be a property, not a function, for you to use it with neither parens () nor a reference operator ::.)

(To be fair, it’s a little confusing that the Android class enclosing class is called R, as a single capital is usually a type parameter; and also that the nested class is called string, as class names almost always start with a capital letter. And also that its properties are a mixture of camelCase, PascalCase, snake_case, and some combinations of those! But despite that, the documentation is clear on what’s what.)