FlatButton(
                              materialTapTargetSize:
                                  MaterialTapTargetSize.shrinkWrap,
                              splashColor: Colors.transparent,
                              onPressed: () {
                                controllerName.text = '';
                                controllerDescription.text = '';
                                controllerName.text = task.name;
                                controllerDescription.text = task.title;
                                setState(() {
                                  data = data;
                                  showEditForm = !showEditForm;
                                });
                              },
                              padding: EdgeInsets.all(0.0),
                              child: BuildSvg('assets/svg/dots.svg'),
                            ),

FutureBuilder<List<Task>>(
      future: DBHelper().getTasks(),
      builder: (BuildContext context, AsyncSnapshot<List<Task>> snapshot) {
        if (snapshot.hasData) {
          var data = snapshot.data;
...

child: Dismissible(
                          key: UniqueKey(),
                          crossAxisEndOffset: -0.1,
                          onDismissed: (direction) {
like this                 setState(() {data = data })
                            if (direction == DismissDirection.endToStart) {
                              DBHelper().delete(task.id);
                            } else {
                              DBHelper().delete(task.id);
                            }
                          },
                          child: Container(
                            height: device.height * 585 / 812,
                            child: buildTask(device, task, data),
                          ),
                        ),