how to make model class for complex json in flutter

To create a model class for complex JSON in Flutter, you can follow these steps:

  1. Analyze the JSON structure: Take a close look at the JSON data you have and identify its structure, including the different fields and their types.

  2. Generate the model class: Flutter provides a handy tool called json_serializable that can automatically generate model classes based on JSON data. To use it, you need to add the json_annotation and json_serializable dependencies to your pubspec.yaml file.

yaml dependencies: json_annotation: ^4.4.0 json_serializable: ^4.1.4

  1. Create the model class: In your Dart file, import the necessary packages and define your model class. Annotate the class with @JsonSerializable() to enable code generation.

```dart import 'package:json_annotation/json_annotation.dart';

part 'your_model_class.g.dart';

@JsonSerializable() class YourModelClass { // Define the fields of your model class based on the JSON structure final String field1; final int field2; // ...

   required this.field1,
   required this.field2,
   // ...

 // Add a factory constructor for JSON deserialization
 factory YourModelClass.fromJson(Map<String, dynamic> json) =>

 // Add a method for JSON serialization
 Map<String, dynamic> toJson() => _$YourModelClassToJson(this);

} ```

  1. Generate the model class: Run the following command in your terminal to generate the necessary code for JSON serialization and deserialization:

flutter pub run build_runner build

This command will generate the file your_model_class.g.dart that contains the necessary code for JSON serialization and deserialization.

  1. Use the model class: Now you can use your model class to parse JSON data. For example, if you have a JSON string, you can parse it like this:

dart String jsonString = '{"field1": "value1", "field2": 42}'; Map<String, dynamic> json = jsonDecode(jsonString); YourModelClass model = YourModelClass.fromJson(json);

You can access the fields of the model class like any other Dart object:

dart print(model.field1); // Output: value1 print(model.field2); // Output: 42

That's it! You now have a model class that can handle complex JSON data in Flutter. Remember to adjust the field types and names according to your JSON structure.