/Dart/Dart he default constructor is already defined. Try giving one of the constructors a name.

Dart he default constructor is already defined. Try giving one of the constructors a name.

In dart you can not have the same method/constructor name used several times 
(even with different parameters).

In your case you can either use named constructor to define 2 constructors :

class FirstClass {
  FirstClass() {}
  FirstClass.withA(a) {}
}

Source: stackoverflow.com

Similar codes

0 vote109 views1 answer
Dartlang group array by key
Dart
0 vote108 views1 answer
Restrict back button
Dart
11 votes105 views2 answers
Flutter stateful widget
Dart
3 votes104 views3 answers
App bar color flutter
Dart
20 votes140 views5 answers
Flutter screen size
Dart
0 vote106 views1 answer
How to change the shape of a buton in flutter to cicular
Dart
7 votes101 views2 answers
Flutter opacity
Dart
4 votes113 views2 answers
RenderBox was not laid out: RenderRepaintBoundary#5141b relayoutBoundary=up5 NEEDS-PAINT 'package:flutter/src/rendering/box.dart': package:flutter/…/rendering/box.dart:1 Failed assertion: line 1930 pos 12: 'hasSize'
Dart
4 votes107 views1 answer
Rounded raisedbutton in flutter
Dart
1 vote96 views2 answers
Dart filter list
Dart