_TypeError (type 'Null' is not a subtype of type 'String') Flutter-CodePudding

This project really hated me of coding,can anyone help me? What I’m doing wrong here? https://imgur.com/a/ptNwnCu

CodePudding user response：

The Source object which you are returning in Line 8 is expecting a type String for both id and name. You might not be getting a key named id from the JSON, that's why the TypeError is coming.

You can add a null check operator to not get any exceptions.

return Source(id: json['id'] ?? "", name: json['name'] ?? "")

Now if the keys id and name do not exist in the JSON then an empty string will be returned.

CodePudding user response：

class Source {
    Source({
        this.id,
        this.name,
    });

    String? id;
    String name;

    factory Source.fromJson(Map<String, dynamic> json) => Source(
        id: json["id"] == null ? null : json["id"],
        name: json["name"] == null ? null : json["name"],
    );

    Map<String, dynamic> toJson() => {
        "id": id == null ? null : id,
        "name": name == null ? null : name,
    };
}

You are missing the null check for the json data. Your class should look like above.