How request permissions with Jetpack Compose?

问题

How should be implemented requesting permission from Jetpack Compose View? I'm trying implement application accessing Camera with Jetpack Compose. I tried example from How to get Current state or context in Jetpack Compose Unfortunately example is no longer working with dev06.

        fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
            ContextCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
        }
    }
}

回答1:

A little late but this might help as I had the problem today:

With ContextAmbient.current it is not guaranteed that you have an activity or fragment thus I created my own ambient for handling permissions.

val AmbientPermissionHandler: ProvidableAmbient<PermissionHandler> =
    ambientOf { throw IllegalStateException("permission handler is not initialized") }

// Activity:
private val permissionHandler = PermissionHandler(this)
// onCreate:
setContent {
    Providers(
        AmbientPermissionHandler provides permissionHandler
    ) {/* Composable Contnent */}

Usage:

@Composable
fun PermissionHandler(
    permissions: Array<out String>,
    requestCode: Int,
    granted: @Composable() () -> Unit,
    denied: @Composable() () -> Unit,
    deniedPermanently: (@Composable() () -> Unit)? = null,
    rational: (@Composable() () -> Unit)? = null,
    awaitResult: (@Composable() () -> Unit)? = null,
) {
    val permissionHandler = AmbientPermissionHandler.current
    val (permissionResult, setPermissionResult) = remember(permissions) { mutableStateOf<PermissionResult?>(null) }
    LaunchedEffect(Unit) {
        setPermissionResult(permissionHandler.requestPermissionsSuspend(requestCode, permissions))
    }
    when (permissionResult) {
        is PermissionResult.PermissionGranted -> granted()
        is PermissionResult.PermissionDenied -> denied()
        is PermissionResult.PermissionDeniedPermanently -> deniedPermanently?.invoke()
        is PermissionResult.ShowRational -> rational?.invoke()
        null -> awaitResult?.invoke()
    }
}

Implementation of PermissionHandler with dependency https://github.com/sagar-viradiya/eazypermissions

class PermissionHandler(
    private val actualHandler: AppCompatActivity,
) {
    suspend fun requestPermissionsSuspend(requestCode: Int, permissions: Array<out String>): PermissionResult {
        return PermissionManager.requestPermissions(actualHandler, requestCode, *permissions)
    }

    fun requestPermissionsWithCallback(requestCode: Int, permissions: Array<out String>, onResult: (PermissionResult) -> Unit) {
        actualHandler.lifecycleScope.launch {
            onResult.invoke(PermissionManager.requestPermissions(actualHandler, requestCode, *permissions))
        }
    }
}

If you prefer a callback the second function works also.

回答2:

private const val PERMISSIONS_REQUEST_CODE = 10
private val PERMISSIONS_REQUIRED = arrayOf(Manifest.permission.CAMERA)

@Composable
fun PermissionButton() {

    val context = ContextAmbient.current

    Button(onClick = {
        if (!hasPermissions(context)) {
            requestPermissions(
                context as Activity,
                PERMISSIONS_REQUIRED,
                PERMISSIONS_REQUEST_CODE
            )
        }
    }
    ) {}
}

fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
    ContextCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
}

来源：https://stackoverflow.com/questions/60608101/how-request-permissions-with-jetpack-compose

标签

android

android-jetpack-compose