Bool with json in flutter - json

Question

Hello I am trying to put the variable 'select' to fetch the bool value from a Json file I am not able to do anyone can help me (there is no code all I can get text but I can’t get bool). Thank you.
final _toDoController = TextEditingController();
Map<String, dynamic> _toDoList = Map(); //change this.
void initState() {
super.initState();
_readData().then((data) {
setState(() {
_toDoList = json.decode(data);
});
});
}
void _addToDo() {
setState(() {
Map<String, dynamic> newToDo = Map();
newToDo['verificar'] = true;
_toDoList.addAll(newToDo);
_saveData();
});
}
Widget build(BuildContext context) {
bool selected = _toDoList['verificar'];
return Scaffold(
...
),
body: Container(
color: selected ? Colors.green.withOpacity(0.90) : Colors.deepOrangeAccent.withOpacity(0.90),
...
),
);
}
Future<File> _getFile() async {
final directory = await getApplicationDocumentsDirectory();
return File("${directory.path}/data.json");
}
Future<File> _saveData() async {
String data = json.encode(_toDoList);
final file = await _getFile();
return file.writeAsString(data);
}
Future<String> _readData() async {
try {
final file = await _getFile();
return file.readAsString();
} catch (e) {
return null;
}}}

Answer 1

The problem is the type of list you are using.
List _toDoList = []; //this returns an index based list.
Map<String, dynamic> newTodo = Map(); //this list returns a list with a key and value pair
The solution is to either change _toDoList from index based List to a Map, or access the list using an index.
Map<String, dynamic> _toDoList = Map(); //change _toDoList to this
_toDoList.addAll(newToDo); //change to this
bool selected = _toDoList['verificar'] //this now works
or, with current code as it is, below works.
bool selected _toDoList[0]['verificar'];
Hint:
Print out the run type of a list or variable to see what it is, then it becomes easier to deal access it.
print('a: ${_toDoList.runtimeType} : $_toDoList');
print('b: ${_toDoList[0].runtimeType} : ${_toDoList[0]}');
print('c: ${_toDoList[0]['verificar']}');
Map<String, dynamic> newToDo = Map();
newToDo['verificar'] = true;
Map<String, dynamic> _toDoList2 = Map();
_toDoList2.addAll(newToDo);
print('d: ${_toDoList2.runtimeType} : ${_toDoList2['verificar']}');
and see output, which tells you what type of list this is:
I/flutter (11261): a: List<dynamic> : [{verificar: true}]
I/flutter (11261): b: _InternalLinkedHashMap<String, dynamic> : {verificar: true}
I/flutter (11261): c: true
I/flutter (11261): d: _InternalLinkedHashMap<String, dynamic> : true
In summary, below works
Map<String, dynamic> _toDoList = Map(); //change this.
void initState() {
super.initState();
_readData().then((data) {
setState(() {
_toDoList = json.decode(data);
});
});
}
void _addToDo() {
setState(() {
Map<String, dynamic> newToDo = Map();
newToDo['verificar'] = true;
_toDoList.addAll(newToDo);
_saveData();
});
}
#override
Widget build(BuildContext context) {
bool selected = _toDoList[verificar];