SweetSheet improvement - 3/3 :Provide proper async/await handling for returning data

[MsXam]

Hi

showModalBottomSheet provides a return value of Future. However - the current implementation of SweetSheet does not provide a provision to return action data choices (Return values when buttons are tapped). It is therefore suggested to correctly amend the signature of show() to capture return data.

Future<dynamic> show({
    @required BuildContext context,
    Widget title,
    @required Widget description,
    @required CustomSheetColor color,
    @required SweetSheetAction positive,
    SweetSheetAction negative,
    bool useRootNavigator = false,
    IconData icon,
  }) {
    var rv = showModalBottomSheet(...);
    return rv;
  }

And this can then be accessed as in a specific warning helper method that just wraps SweetSheetColor.WARNING & Associated Icon

  static Future<dynamic> warning(
      String title, String description, BuildContext context) async {
    assert(title != null);
    assert(description != null);
    var rv = await bottomDialog(context, Text(title),
        description: Text(description),
        color: SweetSheetColor.WARNING,
        icon: 'yourAssetFile.zip',
        useRootNavigator: true);
    return rv;
  }

An example of how the SweetSheet.bottomDialog can be called and how we now process the Navigator return values is :

var continueRunning = await SweetSheetHelper.bottomDialog(
          context, Text('This is your title'),
          description: Text(
              'This is your description'),
          color: SweetSheetColor.WARNING,
          icon: 'assets/lottie/warningWhiteCircle.zip',
          useRootNavigator: true,
          positive: SweetSheetAction(
            icon: MdiIcons.runFast,
            title: 'CONTINUE',
            onPressed: () =>
                Navigator.of(context, rootNavigator: true).pop(true),
          ),
          negative: SweetSheetAction(
            title: 'CANCEL',
            onPressed: () =>
                Navigator.of(context, rootNavigator: true).pop(false),
          ));

      /// And here you will be able to get the RETURN values from the navigators (true/false/null etc)
     
      if (continueRunning == null || !continueRunning) {
        return; // User tapped cancel or discarded the MODAL sheet 
      }