PermissionHelper.kt

package io.github.sceneview.ar.utils

import android.Manifest
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.net.Uri
import android.provider.Settings
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.result.contract.ActivityResultContracts
import androidx.core.content.ContextCompat
import androidx.fragment.app.Fragment
import io.github.sceneview.ar.R

/**
 * Helper to ask camera permission
 */
object PermissionHelper {

    /**
     * Check to see if we have the necessary permissions for Camera
     */
    fun hasCameraPermission(context: Context) = ContextCompat.checkSelfPermission(
        context,
        Manifest.permission.CAMERA
    ) == PackageManager.PERMISSION_GRANTED

    /**
     * Request the Camera permission
     *
     * Must be called at the onCreate() time (before onResume()).
     * Use your own permission check if you need to call it elsewhere.
     *
     * @param onDenied Callback on permission denied and !shouldShowRequestPermissionRationale.
     * Return true to show the permission settings.
     * @param onGranted Callback to start using the camera
     */
    fun requestCameraPermission(
        activity: ComponentActivity,
        onDenied: () -> Boolean = {
            Toast.makeText(
                activity,
                R.string.sceneview_camera_permission_required,
                Toast.LENGTH_LONG
            ).show()
            true
        }, onGranted: () -> Unit
    ) {
        // Must be called before on resume
        val activityResultLauncher = activity.registerForActivityResult(
            ActivityResultContracts.StartActivityForResult()
        ) {
            if (hasCameraPermission(activity)) {
                onGranted()
            }
        }
        // Must be called before on resume
        val permissionResultLauncher = activity.registerForActivityResult(
            ActivityResultContracts.RequestPermission()
        ) { isGranted: Boolean ->
            if (isGranted) {
                onGranted()
            } else if (!activity.shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)) {
                if (onDenied()) {
                    // Launch Application Setting to grant permission
                    activityResultLauncher.launch(
                        Intent().apply {
                            action = Settings.ACTION_APPLICATION_DETAILS_SETTINGS
                            data = Uri.fromParts("package", activity.packageName, null)
                        })
                }
            }
        }
        permissionResultLauncher.launch(Manifest.permission.CAMERA)
    }

    /**
     * Request the Camera permission
     *
     * Must be called at the onCreate() time (before onResume()).
     * Use your own permission check if you need to call it elsewhere.
     *
     * @param onDenied Callback on permission denied and !shouldShowRequestPermissionRationale.
     * Return true to show the permission settings.
     * @param onGranted Callback to start using the camera
     */
    fun requestCameraPermission(
        fragment: Fragment,
        onDenied: () -> Boolean = {
            Toast.makeText(
                fragment.requireContext(),
                R.string.sceneview_camera_permission_required,
                Toast.LENGTH_LONG
            ).show()
            true
        },
        onGranted: () -> Unit
    ) {
        // Must be called before on resume
        val activityResultLauncher = fragment.registerForActivityResult(
            ActivityResultContracts.StartActivityForResult()
        ) {
            if (hasCameraPermission(fragment.requireContext())) {
                onGranted()
            }
        }
        // Must be called before on resume
        val permissionResultLauncher = fragment.registerForActivityResult(
            ActivityResultContracts.RequestPermission()
        ) { isGranted: Boolean ->
            if (isGranted) {
                onGranted()
            } else if (!fragment.shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)) {
                if (onDenied()) {
                    // Launch Application Setting to grant permission
                    activityResultLauncher.launch(
                        Intent().apply {
                            action = Settings.ACTION_APPLICATION_DETAILS_SETTINGS
                            data = Uri.fromParts(
                                "package",
                                fragment.requireContext().packageName,
                                null
                            )
                        })
                }
            }
        }
        permissionResultLauncher.launch(Manifest.permission.CAMERA)
    }
}