Flutter Stateless Widget initialize values by keeping the constructor as "const"

Question

I want to map a List of Strings to a List of DropdownMenuItems in the Widget constructor. The parent widget passes a List of Strings to the child widget. The child widget must map this List of Strings to a List of DropdownMenuItems. I want to do that in the constructor while keeping the constructor "const". Is that possible? There is a "initState" method for the statefull widgets but I can't find a similar method for the stateless widgets

const SelectableEntry({
  Key? key,
  required this.dropdownList,
})  : mappedList =
          const dropdownList.map((string entry) => DropdownMenuItem<String>(
                value: entry,
                child: Text(entry),
              )).toList(),
      super(key: key);

final List<String> dropdownList;
final List<DropdownMenuItem<String>> mappedList;

@override

...

you can shift the `mappedList` inside build method – Md. Yeasin Sheikh Mar 11 '23 at 15:47 — Md. Yeasin Sheikh, Mar 11 '23 at 15:47

score 0 · Answer 1 · answered Mar 12 '23 at 18:55

If you don't need mappedList to be mutable (and I suppose you don't, as you would lose the changes in mappedList in each rebuild if you're not placing it in the State of a StatefulWidget) you can make the mappedList a getter:

List<DropdownMenuItem<String>> get mappedList => dropdownList
   .map(
     (entry) => DropdownMenuItem<String>(
       value: entry,
       child: Text(entry),
     ),
   )
   .toList();

Flutter Stateless Widget initialize values by keeping the constructor as "const"

1 Answers1