Exposing CameraController in Compose.

CameraControllCompose.kt

import androidx.camera.core.CameraSelector
import androidx.camera.view.CameraController
import androidx.camera.view.LifecycleCameraController
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.compositionLocalOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.platform.LocalLifecycleOwner
import kotlinx.coroutines.guava.await


val LocalCameraController =
    compositionLocalOf<CameraController> { error("CameraController wasn't provided") }

data class CameraControllerScope(
    val isPrepared: Boolean = false,
    val cameraController: CameraController
)


@Composable
fun CameraController(
    lensFacing: Int = CameraSelector.LENS_FACING_FRONT,
    cameraSelector: CameraSelector =
        if (lensFacing == CameraSelector.LENS_FACING_BACK) CameraSelector.DEFAULT_BACK_CAMERA
        else CameraSelector.DEFAULT_FRONT_CAMERA,
    content: @Composable CameraControllerScope.() -> Unit
) {
    val context = LocalContext.current
    val cameraController = remember { LifecycleCameraController(context) }
    var scope by remember(cameraController) {
        mutableStateOf(CameraControllerScope(cameraController = cameraController))
    }
    val lifecycleOwner = LocalLifecycleOwner.current
    LaunchedEffect(lensFacing, cameraSelector) {
        kotlin.runCatching {
            cameraController.initializationFuture.await()
            scope = scope.copy(isPrepared = false)
        }.onSuccess {
            cameraController.cameraSelector = cameraSelector
            cameraController.bindToLifecycle(lifecycleOwner)
        }.onFailure {
            it.printStackTrace()
        }
    }
    CompositionLocalProvider(
        LocalCameraController provides cameraController,
    ) {
        content(scope)
    }
}

@Composable
fun Usage() {
    CameraController {
        val controller = LocalCameraController.currnet
        //or 
        val cameraController = cameraController //from CameraControllerScope
        MyContent()
       
    }
}