Contents

Updated `Checkbox.fillColor` behavior

Contents

Summary
Context
Description of change
Migration guide
Timeline
References

The Checkbox.fillColor is now applied to the checkbox's background when the checkbox is unselected.

Previously, the Checkbox.fillColor was applied to the checkbox's border when the checkbox was unselected and its background was transparent. With this change, the Checkbox.fillColor is applied to the checkbox's background and the border uses the Checkbox.side color when the checkbox is unselected.

The Checkbox.fillColor is now applied to the checkbox's background when the checkbox is unselected instead of being used as the border color.

The updated Checkbox.fillColor behavior applies the fill color to the checkbox's background in the unselected state. To get the previous behavior, set Checbox.fillColor to Colors.transparent in the unselected state and set Checkbox.side to the desired color.

If you use the Checkbox.fillColor property to customize the checkbox.

Code before migration:

dartCheckbox(
  fillColor: MaterialStateProperty.resolveWith((states) {
    if (!states.contains(MaterialState.selected)) {
      return Colors.red;
    }
    return null;
  }),
  value: _checked,
  onChanged: _enabled
    ? (bool? value) {
        setState(() {
          _checked = value!;
        });
      }
    : null,
),

Code after migration:

dartCheckbox(
  fillColor: MaterialStateProperty.resolveWith((states) {
    if (!states.contains(MaterialState.selected)) {
      return Colors.transparent;
    }
    return null;
  }),
  side: const BorderSide(color: Colors.red, width: 2),
  value: _checked,
  onChanged: _enabled
    ? (bool? value) {
        setState(() {
          _checked = value!;
        });
      }
    : null,
),

If you use the CheckboxThemeData.fillColor property to customize the checkbox.

Code before migration:

dartcheckboxTheme: CheckboxThemeData(
  fillColor: MaterialStateProperty.resolveWith((states) {
    if (!states.contains(MaterialState.selected)) {
      return Colors.red;
    }
    return null;
  }),
),

Code after migration:

dartcheckboxTheme: CheckboxThemeData(
  fillColor: MaterialStateProperty.resolveWith((states) {
    if (!states.contains(MaterialState.selected)) {
      return Colors.transparent;
    }
    return null;
  }),
  side: const BorderSide(color: Colors.red, width: 2),
),