Flutter AnimatedScrollView: 'itemIndex' out of bounds error

This error occurs in the Flutter framework when using the 'AnimatedScrollView' widget and passing an invalid index value for the 'itemsCount' parameter. The 'itemsCount' parameter represents the total number of items in the scrollable list, and the 'itemIndex' parameter represents the index of the currently selected item.

To fix this error, ensure that the 'itemIndex' value is within the valid range of 0 to ('_itemsCount' - 1). Also, make sure that the '_itemsCount' value is correctly initialized and updated when adding or removing items from the scrollable list.