enableReaderMode method

Future<void> enableReaderMode({ required Set<NfcReaderFlag> flags, required Future<void> onDiscovered(NfcTag tag), Future<void> onError(NfcError error)?, Duration presenceCheckDelay = const Duration(milliseconds: 250), })

Starts reader mode with exactly flags, bypassing the cross-platform mapping.

The tag and error callbacks are the session's, so register them the same way NfcUtil.startSession does.

Throws an ArgumentError, before the platform is touched, for an empty flags or a presenceCheckDelay outside zero to 0x7fffffff milliseconds.

Implementation

Future<void> enableReaderMode({
  required Set<NfcReaderFlag> flags,
  required Future<void> Function(NfcTag tag) onDiscovered,
  Future<void> Function(NfcError error)? onError,
  Duration presenceCheckDelay = const Duration(milliseconds: 250),
}) async {
  // Unlike the cross-platform config, the raw flag list has no fallback on the Android
  // side: an empty set is passed through as flags `0`, which starts reader mode polling
  // for nothing at all. This stays a raw escape hatch, so only emptiness is rejected --
  // which flags make sense together is the caller's business.
  if (flags.isEmpty) {
    throw ArgumentError.value(flags, 'flags', 'is empty; reader mode would poll for nothing');
  }
  final presenceCheckDelayMillis = presenceCheckDelayToWire(presenceCheckDelay, 'presenceCheckDelay');

  final restore = NfcCallbacks.instance.armSession(tag: onDiscovered, error: onError);

  try {
    await androidApi.enableReaderMode(flags.map(_flagToWire).toList(), presenceCheckDelayMillis);
  } on Object {
    // Restores rather than clears, so a refused start leaves a session that is still
    // running exactly as it was.
    restore();
    rethrow;
  }
}