The method '_image' isn't defined for the type '_xxxxState'. (Documentation) Try correcting the name to the name of an existing method, or defining a method named '_image'.

[Leopold2024]

 RatingBar(
                      initialRating: 3,
                      direction: Axis.horizontal,
                      allowHalfRating: true,
                      itemCount: 5,
                      ratingWidget: RatingWidget(
                        full: _image('assets/images/heart.png'),
                        half: _image('assets/images/heart_half.png'),
                        empty: _image('assets/images/heart_border.png'),
                      ),
                      itemPadding: EdgeInsets.symmetric(horizontal: 4.0),
                      onRatingUpdate: (rating) {
                        print(rating);
                      },
                    )

The method '_image' isn't defined for the type '_xxxxState'. (Documentation) Try correcting the name to the name of an existing method, or defining a method named '_image'.