Capturing Screenshot doesn't work in HookWidget about screenshot HOT 1 CLOSED

Screenshot(
key:GlobalKey() //By adding this, problem is solved
            //Supply the screenshotController to Screenshot widget
            controller: screenshotController,
            child: AnimatedContainer(
              curve: Curves.easeInOutCirc,
              duration: const Duration(milliseconds: 700),
              padding: const EdgeInsets.fromLTRB(0, 10, 0, 10),
              alignment: Alignment.center,
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topLeft,
                  end: Alignment.bottomRight,
                  colors: backGroundColor.value,
                ),
              ),
            child: Text('Hello World'),
            ),
          ),