Issue with null values-CodePudding

I'm just studying Flutter and get the following error:

Unhandled Exception: type 'Null' is not a subtype of type 'int'

This is a basic app that fetches some data from an API. Then I would like to show the result in separate cards. It may happen, that some variables will get null because there is no data for this. Eg:(there are no ratings).

This is the class itself:

class Movies {
  late int movieId;
  late String title;
  late String description;
  late String date;
  late String poster;
  late String header;
  late double vote;

  Movies(
      {required this.movieId,
      required this.title,
      required this.description,
      required this.date,
      required this.poster,
      required this.header,
      required this.vote});

  Movies.empty();
}

And this is the part where the error is thrown

Connection connection = Connection();
  List<Movies> movieTitle = [];
  bool loaded = false;

  Future<void> createlist() async {
    String response = await connection.getMovieByTitle(widget.queryText);
    var data = jsonDecode(response);
    var results = data['results'];
    for (int i = 0; i < results.length; i  ) {
      movieTitle.add(
        Movies(
            movieId: data['id'],
            title: data['original_title'],
            description: data['overview'],
            date: data['release_date'],
            poster: data['poster_path'],
            vote: data['vote_average'],
            header: data['backdrop_path']),
      );
    }
    setState(() {
      loaded = true;
    });
  }

What would be the solution?

CodePudding user response：

Make your fields nullable if the API response have null values. For example: String?

CodePudding user response：

Convert your class to:

class Movies {
  int? movieId;
  String? title;
  String? description;
  String? date;
  String? poster;
  String? header;
  double? vote;

  Movies({
    required this.movieId,
    required this.title,
    required this.description,
    required this.date,
    required this.poster,
    required this.header,
    required this.vote,
  });

  Movies.empty();
}