Flutter: Jump out of "Focus" Widget on key pressed

Question

I want to traverse a Focus-Group with arrow keys, so that the next/previous focusNode is selected. On tab/shift+tab I want the focus to jump out of that focus group, to the next/previous focusNode OUTSIDE my Focus-Group:

Focus(
  onKey: (focusNode, event) {
     if (event.runtimeType == RawKeyDownEvent) {
      if (event.logicalKey == LogicalKeyboardKey.arrowDown) {
          focusNode.nextFocus();
          return KeyEventResult.handled;

      } else if (event.logicalKey == LogicalKeyboardKey.arrowUp) {
          focusNode.previousFocus();
          return KeyEventResult.handled;

      } else if (event.logicalKey == LogicalKeyboardKey.tab) {
          if(RawKeyboard.instance.keysPressed.contains(LogicalKeyboardKey.shiftLeft))){ 

            // TODO: JUMP FOCUS OUT OF THIS FOCUS WIDGET 
            // TO THE FOCUS NODE ABOVE/BEFORE THIS FOCUS WIDGET

          } else {

            // TODO: JUMP FOCUS OUT OF THIS FOCUS WIDGET 
            // TO THE FOCUS NODE BELOW/AFTER THIS FOCUS WIDGET

          }
          return KeyEventResult.handled;
      }
     }
     return KeyEventResult.ignored;
  },
  child: ...

Answer 1

Solution was:

bool someoneInListHasPrimaryFocus(Iterable<FocusNode> descendants){
  for (FocusNode fn in descendants) {
    if(fn.hasPrimaryFocus) return true;
  }
  return false;
}

                        Focus(
                          onKey: (focusNode, event) {
                            if (event.runtimeType == RawKeyDownEvent) {
                              if (event.logicalKey == LogicalKeyboardKey.arrowDown || event.logicalKey == LogicalKeyboardKey.arrowRight) {
                                focusNode.nextFocus();
                                return KeyEventResult.handled;
                              } else if (event.logicalKey == LogicalKeyboardKey.arrowUp || event.logicalKey == LogicalKeyboardKey.arrowLeft) {
                                focusNode.previousFocus();
                                return KeyEventResult.handled;
                              } else if (event.logicalKey == LogicalKeyboardKey.tab) {
                                if(RawKeyboard.instance.keysPressed.contains(LogicalKeyboardKey.shiftLeft) || RawKeyboard.instance.keysPressed.contains(LogicalKeyboardKey.shiftRight)){ //You think shiftLeft + shiftRight = shift? HAHAHA think again
                                  FocusNode firstElement = focusNode.descendants.first;
                                  firstElement.requestFocus();
                                  firstElement.previousFocus();
                                } else {
                                  if(someoneInListHasPrimaryFocus(focusNode.descendants)){
                                    FocusNode lastElement = focusNode.descendants.last;
                                    lastElement.requestFocus();
                                    lastElement.nextFocus();
                                  } else {
                                    FocusNode firstElement = focusNode.descendants.first;
                                    firstElement.requestFocus();
                                  }
                                }
                                return KeyEventResult.handled;
                              }
                            }
                            return KeyEventResult.ignored;
                          },
                          child: ...