How to encode list to json?
This is my class for Json.
class Players{
List<Player> players;
Players({this.players});
factory Players.fromJson(List<dynamic> parsedJson){
List<Player> players = List<Player>();
players = parsedJson.map((i)=>Player.fromJson(i)).toList();
return Players(
players: players,
);
}
}
class Player{
final String name;
final String imagePath;
final int totalGames;
final int points;
Player({this.name,this.imagePath, this.totalGames, this.points});
factory Player.fromJson(Map<String, dynamic> json){
return Player(
name: json['name'],
imagePath: json['imagePath'],
totalGames: json['totalGames'],
points: json['points'],
);
}
}
I managed to decode with fromJson, the result is in List. Now that I have another player to add in json and want to encode the list to json, have no idea to do it. It result always failed.
var json = jsonDecode(data);
List<Player> players = Players.fromJson(json).players;
Player newPlayer = Player(name: _textEditing.text,imagePath: _imagePath,totalGames: 0,points: 0);
players.add(newPlayer);
String encode = jsonEncode(players.players);
What do I need to add on Players or Player?
We have 3 steps to convert an Object/List to JSON string: create the class. create toJson() method which returns a JSON object that has key/value pairs corresponding to all fields of the class. get JSON string from JSON object/List using jsonEncode() function.
jsonEncode function Null safetyConverts object to a JSON string. 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.
Add toJson
method to your Player
class:
Map<String, dynamic> toJson(){
return {
"name": this.name,
"imagePath": this.imagePath,
"totalGames": this.totalGames,
"points": this.points
};
}
Then you can call jsonEncode
on the list of players:
String encoded = jsonEncode(players) // this will automatically call toJson on each player
Add on class:
Map<String,dynamic> toJson(){
return {
"name": this.name,
"imagePath": this.imagePath,
"totalGames": this.totalGames,
"points": this.points
};
}
and call
String json = jsonEncode(players.map((i) => i.toJson()).toList()).toString();
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