[Flutter] StatelessWidget 및 StatefulWidget

StatefulWidget 만들기

StatefulWidget 클래스

class FavoriteWidget extends StatefulWidget {
  @override
  _FavoriteWidgetState createState() => _FavoriteWidgetState();
}

State 등급

class _FavoriteWidgetState extends State<FavoriteWidget> {
  bool _isFavorited = true;
  int _favoriteCount = 41;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Container(
          padding: EdgeInsets.all(0),
          child: IconButton(
            padding: EdgeInsets.all(0),
            alignment: Alignment.centerRight,
            icon: (_isFavorited ? Icon(Icons.star) : Icon(Icons.star_border)),
            color: Colors.red[500],
            onPressed: _toggleFavorite,
          ),
        ),
        SizedBox(
          width: 18,
          child: Container(
            child: Text('$_favoriteCount'),
          ),
        ),
      ],
    );
  }
}

void _toggleFavorite() {
  setState(() {
    if (_isFavorited) {
      _favoriteCount -= 1;
      _isFavorited = false;
    } else {
      _favoriteCount += 1;
      _isFavorited = true;
    }
  });
}