Flutter json decode I have looked at various (4 so far) Dart JWT libraries -- but all are either too old and no longer work with Dart 2, etc. The codes are like this Future<Products> Get Product () async { var response = await http. For example: Map<String,dynamic> get bodyJson => convert. image object is a list so use ListView. JSON is always encoded in utf8, so you could: json. Apparently I'm not accessing json correctly. json. Jul 15, 2020 · Dio has a plugin called dio_flutter_transformer that is especially for Flutter and will parse Json in a separate Isolate via the compute function. And for React here Getting Started Decode a token May 2, 2018 · I am trying to convert a dictionary to json string. body); } cat Jun 13, 2023 · Learn how to call and parse nested JSON data from APIs in Flutter. The builders generate code when they find members annotated with classes defined in package:json_annotation. decode(await stream. static List<User> parseUsers(String responseBody Jun 29, 2022 · The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Aug 27, 2018 · I have a Json parsing project in Flutter and the Json is as follows: May 28, 2020 · I need help with json decode in Flutter, I can't list by item of my json, only all item. Oct 12, 2018 · To decode API response string to JSON, json. This is also true for encoding, decoding JSON and displaying image from the network. 15. While this is a step ahead of manually parsing JSON, you’d still have to write extra code that takes that map and puts the values into a new class. 6 days ago · Parses the string and returns the resulting Json object. The following is my code. Jun 27, 2018 · I am using the dart package json_serializable for json serialization. Mar 7, 2023 · Flutter’s built-in dart:convert package contains methods like json. exit - a new feature for fast concurrency with worker isolates in Dart 2. someVariable as double expects a String at the left side. Mar 29, 2022 · Json serialization returns: type 'Null' is not a subtype of type 'String' Issue So I’m trying to build a list (of any kind) from a Json list object in flutter, I’m getting it using REST api the response is a Json list with the fields: type, contact {first_name, last_name}, created_at, uuid. im trying to store my List data in a disk storage using shared preferences, however idk how to convert the json back to DateTime format when trying to fetch data again from memory when i rebuild/re Mar 31, 2020 · You're able to fetch the http Response body by using either Response. May 7, 2025 · I am working on a project in Flutter. For complex JSON you may want to consider using code generation to reduce the boiler plate you have to write. Oct 25, 2024 · Learn how to efficiently parse JSON data in Flutter applications, leveraging Dart's built-in support for JSON encoding and decoding. decode(jsonVariable) then : find your image object like result['images'][[0]['src'] Use the src link in flutter network. When getting a response from server and decoding it via json. ) Nov 2, 2018 · Caution: When you use Json. The advantage of using bodyBytes is it fetches the bytes directly. The key argument is either the integer list index for a list property, the string map key for object properties, or null for the final result. decode like List<Client> clientFromJson(String str) => Jun 26, 2019 · Parse JSON to Map in flutter Asked 6 years, 2 months ago Modified 1 year, 11 months ago Viewed 58k times Feb 25, 2019 · In Flutter doc, it uses jsonEncode(), while in Angular doc, it uses json. The json is the default implementation of JsonCodec Apr 26, 2024 · In Flutter/Dart, you can use the dart:convert library to encode Dart objects into JSON format (jsonEncode) for sending data, and decode JSON data (jsonDecode) back into Dart objects for processing Aug 19, 2025 · If you run the fetchPhotos() function on a slower device, you might notice the app freezes for a brief moment as it parses and converts the JSON. decode or jsonDecode to parse and decode JSON from API. decode`. Take a look at the Dio package on pub to see the list of plugins available: Dec 1, 2020 · Please help me I just tried this code: **try { final response = http. The compute() function runs expensive functions in a background Jul 31, 2025 · Flutter package for rendering JSON data as an interactive hierarchical tree structure with customizable appearance and lazy rendering for improved performance. getData ('/contacts'); final Map<String, dynamic> body = json. Your method should just return a list of objects which each implement a toJson() method that tells how it should be encoded. Throws FormatException if the input is not valid JSON text. Features Supports rendering any valid JSON. Jun 28, 2022 · It can be more difficult to parse JSON strings in Flutter compared to other languages. It's multi-platform and supports mobile, desktop, and browser. 6 days ago · Converts object to a JSON string. decode will only work if I map it as List<dynamic>. Since you're expecting special characters from the http response, it's An in-depth guide to parsing JSON in Dart, including: encoding and decoding JSON defining strongly-typed model classes parsing JSON inside a factory constructor dealing with nullable/optional values data validation serializing back to JSON parsing complex/nested JSON data A follow-up article about code generation with Freezed is planned. decode (decodeSource,reviver) The optional [reviver] function is called once for each object or list property that has been parsed during decoding. i would love to know how i can parse the json right and insert into body of the Oct 6, 2020 · I have worked on decoding/encoding JSONs in my Flutter/Dart app. body); // print (body. This will parse a JSON string similar to Oct 9, 2018 · My Json code is not working - How do I efficiently parse and encode complex json objects in my flutter program. Discover examples, model class creation, and explore tools like json_serializable to Dec 18, 2023 · 1 You can use this library to decode: import 'dart:convert'; It has a method json. get (url); var decodedJson = json. Get a step-by-step guide with examples and best practices. bodyBytes. I'm wondering how can I parse a nested json to a class with generic types. net which returns a json object of String : String and String : [Array of Strings]. This is currently an early release of the library. This package contains a set of high-level functions and classes that make it easy to consume HTTP resources. I have tried decoding it and it gives me gzipped_data as a List of Integers as you can see above. Guide me please fetch function Jan 20, 2019 · The Dart JSON parser converts the property inside json and apparently is clever enough to spit a double type. Basically, the entire communication between the app Feb 5, 2024 · How to Encode and Decode an Object to JSON in Flutter JSON encoding and decoding are essential processes that allow you to convert complex Dart objects into JSON representations and vice versa. Either you should get the source to fix it, or you can try to fix the string yourself by wholesale replacing any occurrence of \' with '. That isn't valid json. The arguments are the property name (String) or list Jul 30, 2024 · Handle Json parsing in separate Isolate in Flutter Parsing Json data on the main thread is a common approach that we all use. or they need the secret to decode the JWT which makes no sense and isn't correct (or possible since I I have string like this, {id:1, name: lorem ipsum, address: dolor set amet} And I need to convert that string to json, how I can do it in dart flutter? thank you so much for your help. I am using dart 2 . Apr 1, 2022 · In this Dart/Flutter tutorial, we’re gonna look at ways to convert/parse JSON string into Object, Nested Object, how to parse JSON array, array of JSON objects into List. It covers which JSON solution to use in different scenarios, and why. What is HTTP? The HTTP is a composable, future-based library for making HTTP requests. Is that even possible? The API I have looks like that: { { "adult":false, ". decode (i)) Flutter 的 jsonDecode 函数能够将 JSON 字符串转换为 Dart 对象，便于操作 JSON 数据，如示例中将用户信息字符串解析并打印。 Mar 7, 2022 · Can anyone tell me how to parse this JSON in flutter. decode return incorrect json Asked 6 years, 11 months ago Modified 6 years, 11 months ago Viewed 4k times Feb 10, 2020 · The JSON parser does not attempt to guess at the type of map elements. Dec 29, 2018 · Flutter: how to decode this complex JSON string Asked 6 years, 9 months ago Modified 6 years, 4 months ago Viewed 4k times May 11, 2018 · I have a problem with the response from the request, where its suppose to have a body with json, but something went wrong and i think is with the json that i send on the body request, because it is a nested json object, and the value of the key is a json object. decode () return map<string,dynamic> value here you set list. Nov 8, 2022 · 对于需要从互联网获取数据的应用程序来说，解析JSON是一项非常常见的任务。 而根据你需要处理的JSON数据的多少，你有两个选择。 手动编写所有的JSON解析代码 用代码生成来自动处理 本指南将重点介绍 Jan 30, 2021 · I'm using the packages: https://pub. You can also customize individual fields by annotating them with JsonKey Jun 14, 2022 · Again. encode(data); If you want to decode (turning a JSON string into a Dart object), your input string should be formatted properly. Oct 16, 2024 · Learn how to decode JSON in Flutter using dart:convert and handle server communication efficiently. With body - this is commonly used if you're expecting plain Strings. Since the header and payload is base64 encoded you can easily know the stored data with no password, you can also know if the token is expired or not. Example: const JsonDecoder decoder = JsonDecoder(); const String jsonString Dec 13, 2024 · Dart JSON UTF-8 Decode is an essential technique for efficiently handling JSON data, especially when transferring data between servers and applications. Overview We’ll make a tiny Flutter app that loads and displays some data from a JSON file called sample. Mar 10, 2023 · Replace json['scheduledTimes'] as List<int> with (json['scheduledTimes'] as List<dynamic>). m Nov 28, 2018 · Flutter - Json. 如何在 Flutter 里使用 JSON。本文涵盖了两种常规的 JSON 使用策略： 手动序列化数据 利用代码生成进行自动序列化数据 不同的项目复杂度不同，用例也不一样。对于较小的概念验证项目或者快速原型，使用代码生成器可能有些过于繁杂。对于具有很多更加复杂的 JSON 模型的应用，手动编码可能很快 May 31, 2019 · You can use the http package in Flutter to make an HTTP GET request to the API endpoint, and then parse the JSON response using the dart:convert library's jsonDecode function. Common uses for this is if you're expecting images to be displayed through parsing bytes. The decoding works just fine, but I have a very nasty problem when encoding my objects to JSON. Oct 4, 2020 · void _getContacts () async { var res = await Network (). get(url); // Giving error here final extractedData = json. collection('emplo Feb 12, 2025 · The dart:convert library (API reference) has converters for JSON and UTF-8, as well as support for creating additional converters. """ }; final jsonString = json. Feb 28, 2022 · Another case here is JSON. 4 days ago · Provides Dart Build System builders for handling JSON. If this was initialized with a reviver, then the parsing operation invokes the reviver on every object or list property that has been parsed. All JSON objects are parsed into maps of type Map<String,dynamic>. decode (respons Parses the string and returns the resulting Json object. Mar 31, 2023 · To convert the JSON data into an array in Flutter, you can use the json. toList())); (Under the hood, http is basically doing that for you; collecting the stream together and doing the character decoding and presenting that as body. Step By Step Aug 12, 2015 · I'd like to make use of Dart's new (experimental) enum feature instead of using stacks of static const Strings, but what's the best way to serialize/deserialize enum variables using JSON? Apr 14, 2022 · When and How to Encode and Decode Josn in Dart | Flutter , jsonEncode, jsonDecode, parse Json network request and json object Apr 29, 2020 · I use this topology model to parse Json data. builder. Apr 22, 2024 · In Flutter, you can parse JSON data received from an API using the dart:convert library, which provides classes and functions for encoding and decoding JSON data. Here is what I have var resBody = {}; resBody["email"] = "emp Sep 15, 2023 · This short, straight-to-the-point article shows you how to read local JSON files in Flutter. And I have the problem, that I can´t get all Values from a Map into a List. My result data to list of all record and render it to ListView in flutter. decode method of Flutter import 'dart:convert'; package. Oct 25, 2024 · Learn how to decode JSON in Flutter applications, transforming JSON data into Dart objects with practical examples, error handling, and best practices. when I am decoding the response I got from the server by using json. instead of this late List catalogdata; use this late var catalogdata; or late Map<string,dynamic> catalogdata; Jul 19, 2023 · I like the way Swift parse JSON and I wanted to make something similar. ホーム / 記事 / マガジン / 【Flutter】JSON形式のデータをDecodeしてDartで扱える型に変換する 2020. A JSON input must be the JSON encoding of a single JSON value, which can be a list or map containing other values. Looking at the flutter documentation it shows how to deserialize a single object as follow: Sep 3, 2019 · Flutter 개발시 JSON데이타를 다루는 법을 배워보자! 어플리케이션 개발시 네트워크 커뮤니케이션이 있다면 JSON을 쓸 가능성이 아주 많다. I'M stucked i created classes successfully but getting errors from parse method Here is The JSON May 19, 2019 · Flutter offers an easy to use HTTP library bundled inside the framework so you won’t need to use a third party package. When I started working with APIs in Flutter, JSON parsing really Mar 2, 2024 · To add a reviver in the json. I want to decode it. 07 Sep 30, 2018 · I am trying to get a JSON array from a webservice URL and parse it in JSON. So, I encode and save it to the database. Then you have to decode that into characters. jsonDecode(utf8. decode(String) the returned object can have a real type of: List<dynamic> Map<String, dynamic> But also when the type is List<dynamic>, decode has parsed also the items in the List, so in your case (since your json has structure [{"" : ""}]) you just need to cast the (reified) List's type parameter with the cast() method. Aug 17, 2019 · The expected response is JSON, but as it is Gzipped and I am unable to decompress it, I do not know how to get the JSON from it. Even tho dart/flutter use C# syntax a lot of the language feels much different than I thought it would. When building Flutter applications, ensuring secure communication between … This short article shows how to perform HTTP requests from a Flutter application. Jun 21, 2022 · I'm new to flutter & dart languages but I'm very comfortable with C# and . tryDecode( jsonEncode(null) ) that function can't tell you if this can convert to JSON or not because the result always is null. My JSON: Mar 28, 2022 · I am using the dart package json_serializable for json serialization. ThemeDecoder -- Provides functionality to decode theme related objects from JSON maps. How I do to use, for example, screenlist. I have about 200 list on data form json file. This provides two main classes. This comprehensive guide will walk you through the entire process, making it easy to understand and implement. You can also explore this website to make a model class. But if you want to create JSON manually, you should ensure that contents is "contents". Dart, the programming language behind Flutter, offers powerful tools to decode JSON, including support for UTF-8 encoded data. May be I am not doing in proper manner But I have couple of question related to converting JSON to Object. Let's learn how to encode and decode JSON in Flutter. こんにちは。いせりゅーです😋 最近、新しいトピックに取り組む際の挑戦や躓きを経験しています。そんな中、業務でのフィードバックを通じて、JSONのエンコード・デコードの理解について新たな気づきを得ました。それを皆さんと共有したいと思います!! 問題の背景 この辺りについ Jan 6, 2022 · Use the toList() method on stream for that. 2k次。本文介绍Flutter中JSON资源的配置与读取方法，包括JSON字符串转换为List和Map的过程，以及通过手动方式和json_serializable插件实现JSON到Model对象的转换。 Nov 13, 2025 · Converts the given JSON-string input to its corresponding object. Mar 15, 2020 · I have this simple dart file which I'm running: import 'dart:convert'; // dynamic test() { final strJson = '{"ACB":["{\\"date\\":\\"2020-02-28\\",\\"open\\":1. Oct 23, 2018 · Below code snippet throws Format Exception in Flutter json decode, Any suggestion please? import 'dart:async' show Future; import 'dart:convert'; Future<String> readBooks() async { String Sep 12, 2020 · How to decode large json array in flutter Asked 5 years, 2 months ago Modified 3 years, 6 months ago Viewed 3k times Nov 17, 2021 · 0 You can decode the code by: var result = json. Jan 29, 2025 · Learn how to deserialize JSON responses in Flutter using the Json serializable package to simplify communication with APIs. cast<int>() That tells the runtime "you will find that that dynamic thing you have (json ['scheduledTimes']) is a List<dynamic>" (it agrees because it tells you it is in the error), "but I can assure you that each of the dynamics in that list is an int Aug 10, 2022 · I'm using jwtDecoder package to decode my token and store it into a userModel. decode() I sometimes get the following error flutter: FormatException: Unexpected character (at character 21) Jul 8, 2018 · Parsing complex JSON in Flutter I have to admit, I was missing the gson world of Android after working with JSON in Flutter/Dart. ThemeEncoder -- Provides functionality to encode Jan 3, 2021 · With dynamic json. Jul 14, 2023 · Learn how to parse JSON and define type-safe model classes that can handle validation, nullable/optional values, and complex/nested JSON data (updated to Dart 3). but I need to take it through url. We have using compute so it wont affect the UI but the long loading time are blocking the users. Single quotes should not be escaped. decode (res. Looking at the flutter documentation it shows how to deserialize a single object as follow: Aug 27, 2022 · I want to decode my json to a List but jsonDecode returns String instead of List. there is an approximate data that is in the template. image. The default [reviver] (when not provided) is the identity function. Dec 31, 2019 · If you want the JSON string to be decoded into a JSON String later onwards, then the best way to convert the JSON String into a string is by using the json. We have a look at the most common request types GET, POST, PUT, and DELETE. decode and json. spawn, and Isolate. Jul 13, 2021 · I want to get list of companies from Mongo db and use it in Flutter application. This tutorial aims to guide you through the process of converting JSON-formatted text into Dart objects, from simple to complex structures. net. I tried many examples that are here, Aug 25, 2018 · I am writing a Flutter/Dart application and am getting a JWT back from an auth server that has some claims I need to use. dev/packages/json_serializable I want to encode/decode a list of objects in my flutter app. runtimeType); } May 14, 2022 · – Ankit Kumar Maurya May 14, 2022 at 5:25 this part History. decode 方法来解码JSON ，使用JSON字符串作为参数。 Aug 24, 2020 · The json decoder then see this as a newline character and creates it as such in the decoded output leading to your desired result when you show it in the Text widget. decode(utf8. May 31, 2022 · The json that you are trying get can have inappropriate format. That allows you to add any value to the map and convert it back to JSON. The optional reviver function is called once for each object or list property that has been parsed during decoding. 6 days ago · JsonDecoder class final This class parses JSON strings and builds the corresponding objects. Oct 30, 2025 · When making network-connected apps, the chances are that it needs to consume some good old JSON, sooner or later. Check the format of your json before parsing. Jul 21, 2023 · Learn how to encode and decode objects to JSON in Flutter and streamline your app's data communication. The json encoder/decoder transforms between strings and object structures, such as lists and maps, using the JSON format. A JsonCodec encodes JSON objects to strings and decodes strings to JSON objects. decode() works fine. Oct 7, 2024 · JSON Web Token (JWT) adalah standar terbuka (RFC 7519) yang mendefinisikan cara untuk secara aman mentransfer informasi antara pihak-pihak… Jul 23, 2025 · In this article, we will learn how to fetch data from the internet or JSON file using the HTTP package in a flutter. Dec 9, 2021 · How to parse large JSON data using compute, Isolate. decode` and `json. For Flutter, `dart:convert` library is your primary tool for `utf8. What they can use, however, is a Dart package called source_gen. Feb 15, 2022 · Note this is a good opportunity to create an extension method on Response because a client API seldomly travels alone. This guide covers everything from basic decoding to advanced techniques using model classes and code generation. I want to store all objects from this token into a model and then access the model. May 2, 2018 · I am trying to convert a dictionary to json string. My intention is to wrap responses from the backend (like loginRespose that contains a token) with a code and a message I Jun 11, 2024 · Understanding JWT Tokens in Flutter Introduction: In the world of mobile app development, security is a paramount concern. 11. Oct 26, 2018 · I am trying to convert success JSON string to Object. May 6, 2021 · JSON. Dart server has following code to fetch data from mongo and send it to client: var list = await db. This guide looks into ways of using JSON with Flutter. My list is too long. I want saving MobileVersionList and AppInfoList data from API into SharedPreferences using this code : Global Provider //! Save AppInfoList To SharedPreferences String _encodeAppInfoList = '' 有了 dart:convert，我们可以用两种方式来序列化这个JSON model。我们来看看这两种方法： 内连序列化JSON 通过查看 dart：转换JSON文档，我们发现可以通过调用 JSON. How to decode JSON in Flutter? The question is simple, but the answer isn't, at least for me. You can remove the jank by moving the parsing and conversion to a background isolate using the compute() function provided by Flutter. Oct 19, 2025 · JSON Parsing: JSON parsing in Flutter involves the extraction and interpretation of data encoded in JSON format, facilitating its integration into the Flutter application's logic and user interface. decode function to convert the JSON string into a map, and then access the array using the keys and indexes. Here is what I have var resBody = {}; resBody["email"] = "emp JWT Decoder This is a small library for decoding a json web token for dart / flutter. I have a restful API in . UTF-8 is a common variable-width encoding that can represent every character in the Unicode character set. Parsed JSON values are of the types num, String, bool, Null, List s of parsed JSON values or Map s from String to parsed JSON values. If value contains objects that are not directly encodable to a JSON string (a value that is not a number, boolean, string, null, list or a map with string keys), the toEncodable function is used to convert it to an object that must be directly encodable. However I am not getting quotes around any of the strings. Mar 28, 2022 · I am using the dart package json_serializable for json serialization. decode(response. If the data is not large enough, it can be parsed quickly and doesn In this video, you will learn JSON serialization in flutter. i This issue about Flutter not Java. If you like this library there's a version for Vue here. dev/packages/json_annotation, https://pub. How do I do it? encode way, String shoppingCartToJson(List<ShoppingCartModel> data) => jsonEncode(data. Also I am getting this exeption in L Aug 9, 2021 · I need to decode the data I receive as utf8. 6 days ago · JSON JSON is a simple text format for representing structured objects and collections. encode(). The thing is the tutorial I was following shows receving one JSOn obj and parsing it but I need to know how to receive a 6 days ago · API docs for the JsonCodec class from the dart:convert library, for the Dart programming language. Aug 10, 2025 · 文章浏览阅读3. To generate to/from JSON code for a class, annotate it with JsonSerializable. JSON is a simple text format for representing structured objects and collections. Apr 11, 2024 · When developing a Flutter application or any project utilizing the Dart language, handling JSON data is a common requirement. I’m new to flutter and I found that json. My "result", list all the Json, I can't list only item "image". But I don't worry about this. encode, which converts a JSON string to a Map and back. I have a project that uses a lot of JSON Strings. 36 6 days ago · Encoder that encodes a single object as a UTF-8 encoded JSON string. Sep 17, 2019 · json flutter flutter-layout flutter-dependencies asked Sep 17, 2019 at 7:46 chaitanya Harde 376 1 2 9 Aug 7, 2023 · I started developing a web-only flutter app and am using dart:convert library to decode a json. この記事は Flutter Advent Calendar 2018 - Qiita の20日目の記事です。 概要 FlutterにおけるJSONのデコード（エンコード）についてまとめます。 まとめ 小規模なプロジェクトでは手動デコードでもいいかもしれませんが、中規模以 Nov 10, 2024 · What serialization, deserialization, encoding, and decoding mean Methods of implementing JSON serialization in Flutter Practical examples in Dart to illustrate these concepts Customization of May 28, 2020 · I'm new to flutter and was working with json. body or Response. There is no Gson library in flutter. My JSON: Aug 7, 2025 · Flutter resources JSON and serialization Shows how Flutter apps can serialize and deserialize both with dart:convert and with json_serializable. It supports lazy rendering of children for improved performance, and offers extensive customization options for styling and appearance. The data become garbled when I receive Chinese characters. What is the difference and preferred way between the two? Apr 16, 2024 · エラーハンドリング FlutterでJSONをDecodeしてMapに変換する際には、エラーハンドリングが重要です。 特に、不正な形式のJSONデータをDecodeしようとした場合や、存在しないキーにアクセスしようとした場合には、エラーが発生します。 I'm getting a null return when I run the following code. encode otherwise it'll strip out essential character from the resultant String, and you'll never be able to decode it using json. I have tried to add utf8. Aug 2, 2018 · Flutter doesn’t currently offer support for reflection, so some techniques available in other contexts (such as the ability of an Android JSON library to inspect classes for annotations at runtime) won’t work for Flutter devs. JSON serialization is the process of converting json to dart and vice versa. May 3, 2021 · I have a question about json in flutter. How can I make an api request. fromJson (json. You should not create JSON manually which is clearly what you are doing here. Dec 9, 2019 · I'm not able to convert server response to model class. Oct 6, 2022 · We are trying to decode a large json string (~200MB) from web api, the dart:convert json decode performance are really bad. decode() This will decode the josnData. This is jank, and you want to get rid of it. Apr 4, 2019 · I am making flutter applications, and I am confused which one to use json. The fact that your map only contains other maps as values might just be a happy coincidence, and make the type of the outer map Map<String, Map<String, dynamic>> would break code which Dec 31, 2020 · I'm trying to parse JSON to an object in Dart, the documentation uses Map type to parse a JSON response. bodyBytes));. tech APIやSQLiteから情報を取得すると、JSON形式で返ってくることがほとんどです。 この記事では、 郵便番号検索API を例に解説していき Flutter JSON Flutter JSON allows you to beautifully render any valid JSON as an interactive hierarchical tree structure in your app. Which one to use? Apr 19, 2021 · This is the json data i have: { "data": [ { "id": "23", "type": "product", "attributes": { "slug" Need help decoding JSON in Flutter app; Unhandled Exception: type 'Null' is not a subtype of type 'String' in type cast Issue I’ve looked at many examples but I’m still struggling to decode the following json in flutter. DECODE returning null value, Flutter Asked 3 years, 11 months ago Modified 3 years, 11 months ago Viewed 621 times Nov 14, 2025 · Table of Contents json_theme Live Example Decoding Schema Validation Class Selection json_theme Library to encode and decode ThemeData and associated objects to / from JSON. maybe that also cause the problem and not initialised. You can provide arguments to JsonSerializable to configure the generated code. Jun 13, 2025 · This tool helps you decode UTF-8 encoded strings or handle Unicode escape sequences in JSON. This encoder works equivalently to first converting the object to a JSON string, and then UTF-8 encoding the string, but without creating an intermediate string. decode, it weirdly becomes a _JsonMap object with _JsonMap objects inside. To use this library, import dart:convert. Is there another way to access json data? Or is it ok to use it like that? Future Class - par Nov 8, 2020 · Flutterラボ｜動画で学ぶFlutter学習サイト Flutter・Dart・Firebaseに関するアプリ制作の技術を学ぶことができます。プログラミング初心者から経験者まで flutterlabo.