Flutter : Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'L-CodePudding

E/flutter (21169): [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: type 'List' is not a subtype of type 'List' in type cast

type of getPatientDataList() is Future<List<List<dynamic>> Function() . and I want to create a List<List<<double>>>. But all time failed.

  getPatientDataList().then((result) {
  dataSize = result.length;

  List<List<double>> list = (result.getRange(0, 500).toList()).cast<List<List<double>>>();
  print("data "   list.toString());

});

CodePudding user response：

try using

getPatientDataList().then((result) {
  dataSize = result.length;

  List<dynamic> list = (result.getRange(0, 500).toList()).cast<List<double>();
  print("data "   list.toString());

});

CodePudding user response：

You can do it like

You can use result.sublist here and wrap with list.

  getPatientDataList().then((result) {
    final dataSize = result.length;
    List<List<double>> list = [
      result.sublist(0, dataSize < 500 ? dataSize : 500).toList()
    ];
  });