Ask Your Question
1

How can I convert a JSON into an object in Flutter and address the NoSuchMethodError: Class '_Map<String, dynamic>' has no instance method 'cast' with matching arguments error?

asked 2023-03-22 11:00:00 +0000

plato gravatar image

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
1

answered 2022-02-25 16:00:00 +0000

bukephalos gravatar image

To convert a JSON into an object in Flutter, you can use the jsonDecode function from the dart:convert package. Here's an example code snippet:

import 'dart:convert';

class YourObject {
  // define the properties of your object here
  String name;
  int age;

  YourObject({this.name, this.age});

  factory YourObject.fromJson(Map<String, dynamic> json) {
    return YourObject(
      name: json['name'],
      age: json['age'],
    );
  }
}

void convertJsonToObject(String jsonString) {
  final Map<String, dynamic> jsonMap = jsonDecode(jsonString);
  final YourObject yourObject = YourObject.fromJson(jsonMap.cast<String, dynamic>());

  // do something with yourObject
}

In the convertJsonToObject function, we first decode the JSON string into a Map<String, dynamic> using jsonDecode. Then we create an instance of the YourObject class using the fromJson factory constructor, which takes a Map<String, dynamic> parameter. However, we need to cast the jsonMap to a Map<String, dynamic> using cast<String, dynamic>() to avoid the NoSuchMethodError error you mentioned.

Make sure to replace YourObject with the name of your own object class, and update the fromJson factory constructor to match the properties of your object.

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account. This space is reserved only for answers. If you would like to engage in a discussion, please instead post a comment under the question or an answer that you would like to discuss

Add Answer


Question Tools

Stats

Asked: 2023-03-22 11:00:00 +0000

Seen: 10 times

Last updated: Feb 25 '22