Flutter 2: Cast List<dynamic> into List<Map<String, String>>?

Question

I am trying to write correctly flutter by precising specific types.

I am collecting data from Json file and try to cast it into a List<Map<String, String>>.

Future<void> _readJson() async {
    final String response = await rootBundle.loadString('lib/assets/vocabulary.json');
    final data = await json.decode(response);
    print(data);
    _words = List<Map<String, String>>.from(data);
  }

However the cast does not works. Even by trying multiple solutions proposed on Stackoverflow, no one is working.

_words is of type List<Map<String, String>>

Here the output I get actually

I/flutter ( 3971): 0
I/flutter ( 3971): [{a: test1, b: test2}, {a: test3, b: test4}, {a: test5, b: test6}]
E/flutter ( 3971): [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Map<String, String>'
E/flutter ( 3971): #0      new List.from (dart:core-patch/array_patch.dart:40:5)
E/flutter ( 3971): #1      _HomePageState._readJson (package:langage_trainer/pages/home/home_page.dart:108:14)
E/flutter ( 3971): <asynchronous suspension>
E/flutter ( 3971): 

Can someone please provide help for casting my data into my _words's type ?

Answer 1

For the cast, I perform a deep copy of my list using specifiers (as List, as Map<String, String) from the object it returns from the json.decode.

Future<void> _readJson() async {
  final String response = await rootBundle.loadString('lib/assets/vocabulary.json');
  final List<Map<String, String>> data = (await json.decode(response) as List)
      .map((e) => e as Map<String, String>).toList();
}