I am working with a Flutter project where I am trying to learn simple http method to work with api where I can make a call and represent the data in a listview. The problem I am facing has to do with parsing where I have been able to make the call the map data and convert it to a simple list but when I try Map json list to character list I get this error
Here is the code
List<Character> data = []; final uri = Uri.parse(baseUri+characters); try{ final response = await http.get( uri, headers: <String, String>{'Content-type' : 'application/json; charset=UTF-8', HttpHeaders.authorizationHeader: access_token, } ); print('uri: $uri'); print(response.statusCode); print(response.body); if(response.statusCode >= 200 && response.statusCode <= 299){ final jsonResponse = json.decode(response.body); print('jsonResponse: $jsonResponse'); final characterList = jsonResponse['characters'] as List; print('CharacterList: $characterList'); print('just checking data'); // Map json list to character list data = characterList.map((json) => Character.fromJson(json)).toList(); print('data: $data'); } }catch(e){ print('error: $e'); return data; } print('Here\'s the data: $data'); return data; }Problem is here
data = characterList.map((json) => Character.fromJson(json)).toList();Full Response Was
I/flutter (23217): 200I/flutter (23217): {"characters":[{"id":1344,"name":"Naruto Uzumaki","images":["https://static.wikia.nocookie.net/naruto/images/d/d6/Naruto_Part_I.png","https://static.wikia.nocookie.net/naruto/images/7/7d/Naruto_Part_II.png"],"debut":{"manga":"Naruto Chapter #1","anime":"Naruto Episode #1","novel":"Naruto: Innocent Heart, Demonic Blood","movie":"Naruto the Movie: Ninja Clash in the Land of Snow","game":"Naruto: Konoha Ninpōchō","ova":"Find the Four-Leaf Red Clover!","appearsIn":"Anime, Manga, Novel, Game, Movie"},"family":{"father":"Minato Namikaze","mother":"Kushina Uzumaki","son":"Boruto Uzumaki","daughter":"Himawari Uzumaki","wife":"Hinata Uzumaki","adoptive son":"Kawaki","godfather":"Jiraiya"},"jutsu":["All Directions Shuriken","Baryon Mode","Big Ball Rasengan","Big Ball Rasenshuriken","Big Ball Spiralling Serial Zone Spheres","Boil Release: Unrivalled Strength","Chakra Transfer Technique","Clone Body Blow","Clone Flying Arrow","Clone Spinning Heel Drop (Anime only)","Combination Transformation","Continuous Tailed BeastI/flutter (23217): jsonResponse: {characters: [{id: 1344, name: Naruto Uzumaki, images: [https://static.wikia.nocookie.net/naruto/images/d/d6/Naruto_Part_I.png, https://static.wikia.nocookie.net/naruto/images/7/7d/Naruto_Part_II.png], debut: {manga: Naruto Chapter #1, anime: Naruto Episode #1, novel: Naruto: Innocent Heart, Demonic Blood, movie: Naruto the Movie: Ninja Clash in the Land of Snow, game: Naruto: Konoha Ninpōchō, ova: Find the Four-Leaf Red Clover!, appearsIn: Anime, Manga, Novel, Game, Movie}, family: {father: Minato Namikaze, mother: Kushina Uzumaki, son: Boruto Uzumaki, daughter: Himawari Uzumaki, wife: Hinata Uzumaki, adoptive son: Kawaki, godfather: Jiraiya}, jutsu: [All Directions Shuriken, Baryon Mode, Big Ball Rasengan, Big Ball Rasenshuriken, Big Ball Spiralling Serial Zone Spheres, Boil Release: Unrivalled Strength, Chakra Transfer Technique, Clone Body Blow, Clone Flying Arrow, Clone Spinning Heel Drop (Anime only), Combination Transformation, Continuous Tailed Beast Balls, Crescent Moon Rasengan, EarI/flutter (23217): CharacterList: [{id: 1344, name: Naruto Uzumaki, images: [https://static.wikia.nocookie.net/naruto/images/d/d6/Naruto_Part_I.png, https://static.wikia.nocookie.net/naruto/images/7/7d/Naruto_Part_II.png], debut: {manga: Naruto Chapter #1, anime: Naruto Episode #1, novel: Naruto: Innocent Heart, Demonic Blood, movie: Naruto the Movie: Ninja Clash in the Land of Snow, game: Naruto: Konoha Ninpōchō, ova: Find the Four-Leaf Red Clover!, appearsIn: Anime, Manga, Novel, Game, Movie}, family: {father: Minato Namikaze, mother: Kushina Uzumaki, son: Boruto Uzumaki, daughter: Himawari Uzumaki, wife: Hinata Uzumaki, adoptive son: Kawaki, godfather: Jiraiya}, jutsu: [All Directions Shuriken, Baryon Mode, Big Ball Rasengan, Big Ball Rasenshuriken, Big Ball Spiralling Serial Zone Spheres, Boil Release: Unrivalled Strength, Chakra Transfer Technique, Clone Body Blow, Clone Flying Arrow, Clone Spinning Heel Drop (Anime only), Combination Transformation, Continuous Tailed Beast Balls, Crescent Moon Rasengan, Earth Release: I/flutter (23217): just checking dataI/flutter (23217): error: NoSuchMethodError: The method 'map' was called on null.I/flutter (23217): Receiver: nullI/flutter (23217): Tried calling: map(Closure: (dynamic) => CharacterElement)This is my model class
//// final character = characterFromJson(jsonString);import 'dart:convert';Character characterFromJson(String str) => Character.fromJson(json.decode(str));String characterToJson(Character data) => json.encode(data.toJson());class Character { List<CharacterElement> characters; int currentPage; int pageSize; int total; Character({ required this.characters, required this.currentPage, required this.pageSize, required this.total, }); factory Character.fromJson(Map<String, dynamic> json) => Character( characters: List<CharacterElement>.from(json["characters"].map((x) => CharacterElement.fromJson(x))), currentPage: json["currentPage"], pageSize: json["pageSize"], total: json["total"], ); Map<String, dynamic> toJson() => {"characters": List<dynamic>.from(characters.map((x) => x.toJson())),"currentPage": currentPage,"pageSize": pageSize,"total": total, };}class CharacterElement { int id; String name; List<String> images; Debut debut; Family? family; List<String> jutsu; List<String>? natureType; Personal personal; Rank? rank; List<String>? tools; VoiceActors voiceActors; List<String>? uniqueTraits; CharacterElement({ required this.id, required this.name, required this.images, required this.debut, this.family, required this.jutsu, this.natureType, required this.personal, this.rank, this.tools, required this.voiceActors, this.uniqueTraits, }); factory CharacterElement.fromJson(Map<String, dynamic> json) => CharacterElement( id: json["id"], name: json["name"], images: List<String>.from(json["images"].map((x) => x)), debut: Debut.fromJson(json["debut"]), family: json["family"] == null ? null : Family.fromJson(json["family"]), jutsu: List<String>.from(json["jutsu"].map((x) => x)), natureType: json["natureType"] == null ? [] : List<String>.from(json["natureType"]!.map((x) => x)), personal: Personal.fromJson(json["personal"]), rank: json["rank"] == null ? null : Rank.fromJson(json["rank"]), tools: json["tools"] == null ? [] : List<String>.from(json["tools"]!.map((x) => x)), voiceActors: VoiceActors.fromJson(json["voiceActors"]), uniqueTraits: json["uniqueTraits"] == null ? [] : List<String>.from(json["uniqueTraits"]!.map((x) => x)), ); Map<String, dynamic> toJson() => {"id": id,"name": name,"images": List<dynamic>.from(images.map((x) => x)),"debut": debut.toJson(),"family": family?.toJson(),"jutsu": List<dynamic>.from(jutsu.map((x) => x)),"natureType": natureType == null ? [] : List<dynamic>.from(natureType!.map((x) => x)),"personal": personal.toJson(),"rank": rank?.toJson(),"tools": tools == null ? [] : List<dynamic>.from(tools!.map((x) => x)),"voiceActors": voiceActors.toJson(),"uniqueTraits": uniqueTraits == null ? [] : List<dynamic>.from(uniqueTraits!.map((x) => x)), };}class Debut { String manga; String anime; String? novel; String? movie; String game; String? ova; AppearsIn appearsIn; Debut({ required this.manga, required this.anime, this.novel, this.movie, required this.game, this.ova, required this.appearsIn, }); factory Debut.fromJson(Map<String, dynamic> json) => Debut( manga: json["manga"], anime: json["anime"], novel: json["novel"], movie: json["movie"], game: json["game"], ova: json["ova"], appearsIn: appearsInValues.map[json["appearsIn"]]!, ); Map<String, dynamic> toJson() => {"manga": manga,"anime": anime,"novel": novel,"movie": movie,"game": game,"ova": ova,"appearsIn": appearsInValues.reverse[appearsIn], };}enum AppearsIn { ANIME_MANGA_GAME, ANIME_MANGA_GAME_MOVIE, ANIME_MANGA_NOVEL_GAME_MOVIE}final appearsInValues = EnumValues({"Anime, Manga, Game": AppearsIn.ANIME_MANGA_GAME,"Anime, Manga, Game, Movie": AppearsIn.ANIME_MANGA_GAME_MOVIE,"Anime, Manga, Novel, Game, Movie": AppearsIn.ANIME_MANGA_NOVEL_GAME_MOVIE});class Family { String? father; String? mother; String? son; String? daughter; String? wife; String? adoptiveSon; String? godfather; String? brother; String? cloneSon; String? familyGrandmother; String? sister; String? nephew; String? uncle; String? adoptiveMother; String? adoptiveSons; String? adoptiveBrother; String? clone; String? godson; String? greatGrandfather; String? grandfather; String? grandmother; String? cousin; String? geneticTemplateParent; String? cloneBrother; String? pet; String? grandson; String? granddaughter; String? granduncle; String? aunt; String? firstCousinOnceRemoved; String? host; String? niece; String? lover; String? creator; String? geneticTemplate; Family({ this.father, this.mother, this.son, this.daughter, this.wife, this.adoptiveSon, this.godfather, this.brother, this.cloneSon, this.familyGrandmother, this.sister, this.nephew, this.uncle, this.adoptiveMother, this.adoptiveSons, this.adoptiveBrother, this.clone, this.godson, this.greatGrandfather, this.grandfather, this.grandmother, this.cousin, this.geneticTemplateParent, this.cloneBrother, this.pet, this.grandson, this.granddaughter, this.granduncle, this.aunt, this.firstCousinOnceRemoved, this.host, this.niece, this.lover, this.creator, this.geneticTemplate, }); factory Family.fromJson(Map<String, dynamic> json) => Family( father: json["father"], mother: json["mother"], son: json["son"], daughter: json["daughter"], wife: json["wife"], adoptiveSon: json["adoptive son"], godfather: json["godfather"], brother: json["brother"], cloneSon: json["clone/son"], familyGrandmother: json["grandmother "], sister: json["sister"], nephew: json["nephew"], uncle: json["uncle"], adoptiveMother: json["adoptive mother"], adoptiveSons: json["adoptive sons"], adoptiveBrother: json["adoptive brother"], clone: json["clone"], godson: json["godson"], greatGrandfather: json["great-grandfather"], grandfather: json["grandfather"], grandmother: json["grandmother"], cousin: json["cousin"], geneticTemplateParent: json["genetic template/parent"], cloneBrother: json["clone/brother"], pet: json["pet "], grandson: json["grandson"], granddaughter: json["granddaughter"], granduncle: json["granduncle"], aunt: json["aunt"], firstCousinOnceRemoved: json["first cousin once removed"], host: json["host"], niece: json["niece"], lover: json["lover"], creator: json["creator"], geneticTemplate: json["genetic template"], ); Map<String, dynamic> toJson() => {"father": father,"mother": mother,"son": son,"daughter": daughter,"wife": wife,"adoptive son": adoptiveSon,"godfather": godfather,"brother": brother,"clone/son": cloneSon,"grandmother ": familyGrandmother,"sister": sister,"nephew": nephew,"uncle": uncle,"adoptive mother": adoptiveMother,"adoptive sons": adoptiveSons,"adoptive brother": adoptiveBrother,"clone": clone,"godson": godson,"great-grandfather": greatGrandfather,"grandfather": grandfather,"grandmother": grandmother,"cousin": cousin,"genetic template/parent": geneticTemplateParent,"clone/brother": cloneBrother,"pet ": pet,"grandson": grandson,"granddaughter": granddaughter,"granduncle": granduncle,"aunt": aunt,"first cousin once removed": firstCousinOnceRemoved,"host": host,"niece": niece,"lover": lover,"creator": creator,"genetic template": geneticTemplate, };}class Personal { String? birthdate; Sex sex; Age? age; Height? height; Weight? weight; BloodType? bloodType; dynamic kekkeiGenkai; dynamic classification; String? tailedBeast; dynamic occupation; List<String> affiliation; dynamic team; dynamic clan; List<String>? titles; String? status; String? kekkeiMra; dynamic partner; String? species; Personal({ this.birthdate, required this.sex, this.age, this.height, this.weight, this.bloodType, this.kekkeiGenkai, this.classification, this.tailedBeast, this.occupation, required this.affiliation, this.team, this.clan, this.titles, this.status, this.kekkeiMra, this.partner, this.species, }); factory Personal.fromJson(Map<String, dynamic> json) => Personal( birthdate: json["birthdate"], sex: sexValues.map[json["sex"]]!, age: json["age"] == null ? null : Age.fromJson(json["age"]), height: json["height"] == null ? null : Height.fromJson(json["height"]), weight: json["weight"] == null ? null : Weight.fromJson(json["weight"]), bloodType: bloodTypeValues.map[json["bloodType"]]!, kekkeiGenkai: json["kekkeiGenkai"], classification: json["classification"], tailedBeast: json["tailedBeast"], occupation: json["occupation"], affiliation: List<String>.from(json["affiliation"].map((x) => x)), team: json["team"], clan: json["clan"], titles: json["titles"] == null ? [] : List<String>.from(json["titles"]!.map((x) => x)), status: json["status"], kekkeiMra: json["kekkeiMōra"], partner: json["partner"], species: json["species"], ); Map<String, dynamic> toJson() => {"birthdate": birthdate,"sex": sexValues.reverse[sex],"age": age?.toJson(),"height": height?.toJson(),"weight": weight?.toJson(),"bloodType": bloodTypeValues.reverse[bloodType],"kekkeiGenkai": kekkeiGenkai,"classification": classification,"tailedBeast": tailedBeast,"occupation": occupation,"affiliation": List<dynamic>.from(affiliation.map((x) => x)),"team": team,"clan": clan,"titles": titles == null ? [] : List<dynamic>.from(titles!.map((x) => x)),"status": status,"kekkeiMōra": kekkeiMra,"partner": partner,"species": species, };}class Age { String? partI; String? partIi; String? academyGraduate; String? chuninPromotion; String? blankPeriod; String? borutoMovie; String? borutoManga; Age({ this.partI, this.partIi, this.academyGraduate, this.chuninPromotion, this.blankPeriod, this.borutoMovie, this.borutoManga, }); factory Age.fromJson(Map<String, dynamic> json) => Age( partI: json["Part I"], partIi: json["Part II"], academyGraduate: json["Academy Graduate"], chuninPromotion: json["Chunin Promotion"], blankPeriod: json["Blank Period"], borutoMovie: json["Boruto Movie"], borutoManga: json["Boruto Manga"], ); Map<String, dynamic> toJson() => {"Part I": partI,"Part II": partIi,"Academy Graduate": academyGraduate,"Chunin Promotion": chuninPromotion,"Blank Period": blankPeriod,"Boruto Movie": borutoMovie,"Boruto Manga": borutoManga, };}enum BloodType { A, AB, B, O}final bloodTypeValues = EnumValues({"A": BloodType.A,"AB": BloodType.AB,"B": BloodType.B,"O": BloodType.O});class Height { String? partI; String? partIi; String? blankPeriod; String? gaiden; String? borutoMovie; String? borutoManga; Height({ this.partI, this.partIi, this.blankPeriod, this.gaiden, this.borutoMovie, this.borutoManga, }); factory Height.fromJson(Map<String, dynamic> json) => Height( partI: json["Part I"], partIi: json["Part II"], blankPeriod: json["Blank Period"], gaiden: json["Gaiden"], borutoMovie: json["Boruto Movie"], borutoManga: json["Boruto Manga"], ); Map<String, dynamic> toJson() => {"Part I": partI,"Part II": partIi,"Blank Period": blankPeriod,"Gaiden": gaiden,"Boruto Movie": borutoMovie,"Boruto Manga": borutoManga, };}enum Sex { FEMALE, FILE_GENDER_VARIOUS_SVG_VARIOUS, MALE}final sexValues = EnumValues({"Female": Sex.FEMALE,"File:Gender Various.svg Various": Sex.FILE_GENDER_VARIOUS_SVG_VARIOUS,"Male": Sex.MALE});class Weight { String? partI; String? partIi; Weight({ this.partI, this.partIi, }); factory Weight.fromJson(Map<String, dynamic> json) => Weight( partI: json["Part I"], partIi: json["Part II"], ); Map<String, dynamic> toJson() => {"Part I": partI,"Part II": partIi, };}class Rank { NinjaRank ninjaRank; String? ninjaRegistration; Rank({ required this.ninjaRank, this.ninjaRegistration, }); factory Rank.fromJson(Map<String, dynamic> json) => Rank( ninjaRank: NinjaRank.fromJson(json["ninjaRank"]), ninjaRegistration: json["ninjaRegistration"], ); Map<String, dynamic> toJson() => {"ninjaRank": ninjaRank.toJson(),"ninjaRegistration": ninjaRegistration, };}class NinjaRank { String? partI; String? gaiden; String? blankPeriod; String? partIi; NinjaRank({ this.partI, this.gaiden, this.blankPeriod, this.partIi, }); factory NinjaRank.fromJson(Map<String, dynamic> json) => NinjaRank( partI: json["Part I"], gaiden: json["Gaiden"], blankPeriod: json["Blank Period"], partIi: json["Part II"], ); Map<String, dynamic> toJson() => {"Part I": partI,"Gaiden": gaiden,"Blank Period": blankPeriod,"Part II": partIi, };}class VoiceActors { dynamic japanese; dynamic english; VoiceActors({ required this.japanese, required this.english, }); factory VoiceActors.fromJson(Map<String, dynamic> json) => VoiceActors( japanese: json["japanese"], english: json["english"], ); Map<String, dynamic> toJson() => {"japanese": japanese,"english": english, };}class EnumValues<T> { Map<String, T> map; late Map<T, String> reverseMap; EnumValues(this.map); Map<T, String> get reverse { reverseMap = map.map((k, v) => MapEntry(v, k)); return reverseMap; }}At the very least is I hope to get a solution for my specific problem. In the best case scenario Im hoping to learn about how the error developed and changes I should be making, why the method I used isnt preffered and if there is auniversal way to do it for both maps and list. I am a biginner currently learning coding and have read different places but no one is explaining it. different solutions arent working and people arent explaining their methods
