How do you properly request and handle runtime camera and photo library permissions in a Flutter app, and what happens if a user denies that permission?

Both Android and iOS require an app to explicitly request camera and photo library permissions at runtime before actually accessing that hardware or data, and the permission_handler package provides a consistent, unified way to check the current permission status, request a needed permission, and appropriately handle the several different possible outcomes, including the user granting the permission, denying it once, or permanently denying it in a way that requires directing the user to the device's own settings screen to manually re enable it.

final status = await Permission.camera.request();
if (status.isGranted) {
  openCamera();
} else if (status.isPermanentlyDenied) {
  openAppSettings();
}