Flutter: final field must be a one of the following-CodePudding

We have a widget class that has a final property of this.type. Currently this is a String and if the String matches one of the available types it returns the correct content via that widget’s builder.

Is there a way that instead of asking for a String, we ask for one of the available potential options.

Eg. Only Block, Fixed or None are acceptable strings. Can we make sure that the use of this widget can only accept those terms.

CodePudding user response：

You can use enums. First declare an enum using the enum keyword:

enum AcceptableOptions { Block, Fixed, None }

Then in your widget, use AcceptableOptions instead of String

class TestWidget extends StatelessWidget {
  const TestWidget({
    required AcceptableOptions option,
  });

  @override
  Widget build(BuildContext context) {
    return Container();
  }
}

TestWidget(option:AcceptableOptions.Block)