An activity that can be extended and can display composables as a bottom sheet

ComposeBottomSheetActivity.kt

/*
To extend this class, make sure it's descendants
add android:theme="@style/Theme.Transparent" to it's manifest tag
 */
@OptIn(ExperimentalMaterialApi::class)
abstract class ComposeBottomSheetActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            val coroutineScope = rememberCoroutineScope()
            val modalBottomSheetState = rememberModalBottomSheetState(ModalBottomSheetValue.Hidden)
            val isSheetOpened = remember { mutableStateOf(false) }

            ModalBottomSheetLayout(
                sheetState = modalBottomSheetState,
                sheetContent = {
                    ScreenContent(coroutineScope, modalBottomSheetState) { 
                        onFinish(coroutineScope, modalBottomSheetState)
                    }
                }
            ) {}

            // Take action based on hidden state
            LaunchedEffect(modalBottomSheetState.currentValue) {
                when (modalBottomSheetState.currentValue) {
                    ModalBottomSheetValue.Hidden -> {
                        handleBottomSheetAtHiddenState(
                            isSheetOpened,
                            modalBottomSheetState
                        )
                    }
                }
            }

            BackHandler {
                onFinish(coroutineScope, modalBottomSheetState)
            }
        }
    }

    // Helper methods
    private suspend fun handleBottomSheetAtHiddenState(
        modalLayoutInitialized: MutableState<Boolean>,
        modalBottomSheetState: ModalBottomSheetState
    ) {
        when {
            !modalLayoutInitialized.value -> initializeModalLayout(modalLayoutInitialized, modalBottomSheetState)
            else -> exit()
        }
    }

    private suspend fun initializeModalLayout(
        isSheetOpened: MutableState<Boolean>,
        modalBottomSheetState: ModalBottomSheetState
    ) {
        isSheetOpened.value = true
        modalBottomSheetState.show()
    }

    open fun exit() = finish()

    private fun onFinish(
        coroutineScope: CoroutineScope,
        modalBottomSheetState: ModalBottomSheetState,
        withResults: Boolean = false,
        result: Intent? = null
    ) {
        coroutineScope.launch {
            if (withResults) setResult(RESULT_OK)
            result?.let { intent = it}
            modalBottomSheetState.hide() // will trigger the LaunchedEffect
        }
    }

    @Composable
    abstract fun ScreenContent(
        coroutineScope: CoroutineScope,
        modalBottomSheetState: ModalBottomSheetState,
        onExit: (() -> Unit?)
    )

    override fun onPause() {
        super.onPause()
        overridePendingTransition(0, 0)
    }


    companion object {
        private val TAG = ComposeBottomSheetActivity::class.java.simpleName
    }
}