build method

Implementation

@override
FormField<DateTime> build({
  required BuildContext context,
  required FormMapper mapper,
  required TypeProperty property,
  required Keywords args}) {
  DateTime? initialValue = mapper.getValue(property);

  final DateFormat dateFormat = args['dateFormat'] ?? DateFormat.yMd();
  final DateTime minDate = args['firstDate'] ?? DateTime(1900);
  final DateTime maxDate = args['lastDate'] ?? DateTime(2100);

  var result = FormField<DateTime>(
    key: ValueKey(property.path),
    initialValue: initialValue,
    validator: (date) {
      try {
        property.validate(date);
        return null;
      }
      catch (e) {
        return e.toString();
      }
    },
    builder: (FormFieldState<DateTime> state) {
      String displayText = state.value != null ? dateFormat.format(state.value!) : 'Tap to select date';

      void _showCupertinoDatePicker() {
        showCupertinoModalPopup(
          context: context,
          builder: (_) => Container(
            height: 250,
            color: CupertinoColors.systemBackground.resolveFrom(context),
            child: CupertinoDatePicker(
              mode: CupertinoDatePickerMode.date,
              backgroundColor: CupertinoColors.systemBackground.resolveFrom(context),
              minimumDate: minDate,
              maximumDate: maxDate,
              initialDateTime: state.value ?? DateTime.now(),
              onDateTimeChanged: (DateTime newDate) {
                state.didChange(newDate);
                mapper.notifyChange(property: property, value: newDate);
              },
            ),
          ),
        );
      }

      return GestureDetector(
        onTap: () {
          // Dismiss keyboard if visible
          FocusScope.of(context).requestFocus(FocusNode());
          _showCupertinoDatePicker();
        },
        child: Container(
          padding: EdgeInsets.symmetric(vertical: 12, horizontal: 12),
          decoration: BoxDecoration(
            border: Border.all(
              color: (state.hasError) ? CupertinoColors.systemRed.resolveFrom(context) : CupertinoColors.separator.resolveFrom(context),
            ),
            borderRadius: BorderRadius.circular(8),
          ),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                displayText,
                style: CupertinoTheme.of(context).textTheme.textStyle,
              ),
              Icon(
                CupertinoIcons.calendar,
                color: CupertinoColors.systemGrey.resolveFrom(context),
              ),
            ],
          ),
        ),
      );
    },
    onSaved: (date) {
      // if you need to save
    },
  );

  // new mapping

  mapper.map(property: property, widget: result, adapter: this);

  // done

  return result;
}