openCamera method

Implementation

Future<String> openCamera() async {
  final completer = Completer<String>();
  _cameraListener(
    callback: (imageUri) {
      completer.complete(imageUri);
    },
  );
  try {
    await _channel.invokeMethod('$_name/openCamera');
  } catch (e) {
    completer.completeError(e);
  }
  return completer.future;
}