How to Use GlobalKeys in multiple widgets using Flutter?

Question

I'm trying to build a responsive navbar using Flutter where I'm using Popupbuttons too. I wanted to show up my PopmenuItems when I put my cursor over the button. To do that I build a Global Keys with a class to fix this, but when I did this, it worked only in one of my Popupmenubuttons. The error was that a Global Key can not be used in more than one widget. Does anyone knows how can I fix this. Below you can find my code.

GlobalKey popUpButtonKey = GlobalKey();

  openPopUpItem() {
    GestureDetector? detector;
    searchForGestureDetector(BuildContext element) {
      element.visitChildElements((element) {
        if (element.widget != null && element.widget is GestureDetector) {
          detector = element.widget as GestureDetector;
        } else {
          searchForGestureDetector(element);
        }
      });
    }

    searchForGestureDetector(popUpButtonKey.currentContext!);

    detector!.onTap!();
  }


body: ListView(
        children: [
          Row(
            children: <Widget>[
              const SizedBox(
                width: 20,
              ),
              SizedBox(
                height: 80,
                width: 185,
                child: Image.asset('assets/images/logo2.png'),
              ),
              Spacer(),
              if (!Responsive.isMobile(context))
                PopupMenuButton(
                    tooltip: '',
                    child: Text(
                      'Escorts',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 24,
                        fontFamily: 'Poppins',
                      ),
                    ),
                    itemBuilder: (BuildContext context) => <PopupMenuEntry>[]),
              Padding(padding: EdgeInsets.all(10.0)),
              if (!Responsive.isMobile(context))
                InkWell(
                  onHover: (value) {
                    if (value) openPopUpItem();
                  },
                  onTap: () {},
                  child: PopupMenuButton(
                      key: popUpButtonKey2,
                      tooltip: '',
                      color: Color(0xFF262533),
                      position: PopupMenuPosition.under,
                      child: Text(
                        'Agenturen & Clubs',
                        style: TextStyle(
                          color: Colors.white,
                          fontSize: 24,
                          fontFamily: 'Poppins',
                        ),
                      ),
                      itemBuilder: (BuildContext context) => <PopupMenuEntry>[
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Escortagenturen',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Bordelle',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Laufhauser',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Saunaclubs',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Domina & BDSM-Studios',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Tantra & Massaage-Studios',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                          ]),
                ),
              Padding(padding: EdgeInsets.all(10.0)),
              if (!Responsive.isMobile(context))
                PopupMenuButton(
                    tooltip: '',
                    child: Text(
                      'Inserieren',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 24,
                        fontFamily: 'Poppins',
                      ),
                    ),
                    itemBuilder: (BuildContext context) => <PopupMenuEntry>[]),
              Padding(padding: EdgeInsets.all(10.0)),
              if (!Responsive.isMobile(context))
                InkWell(
                  onHover: (value) {
                    if (value) openPopUpItem();
                  },
                  onTap: () {},
                  child: PopupMenuButton(
                      key: popUpButtonKey,
                      tooltip: '',
                      color: Color(0xFF262533),
                      position: PopupMenuPosition.under,
                      child: Text(
                        'Werben',
                        style: TextStyle(
                          color: Colors.white,
                          fontSize: 24,
                          fontFamily: 'Poppins',
                        ),
                      ),
                      itemBuilder: (BuildContext context) => <PopupMenuEntry>[
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Werbenformate',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                            const PopupMenuItem(
                              child: ListTile(
                                title: Text(
                                  'Preise',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                            ),
                          ]),
                ),

Answer 1

As the Global Key can not work on multiple widgets, you can create a List of Global Object Key ...

Changing GlobalKey with GlobalObjectKey

 final List<GlobalObjectKey> keyList =
      List.generate(10, (index) => GlobalObjectKey(index));