Is there a way to listen to the current index which is in the viewport?

[mark8044]

Is there a way to listen to the current index which is in the viewport?

This could be very useful to trigger actions when an index is inside the viewport

[jerrywell]

refer to https://github.com/quire-io/scroll-to-index/blob/master/lib/scroll_to_index.dart#L481,

the concept is that you will get the offset to reveal the target widget based on alignment 0 and 1 (means the top and bottom of the viewport).

the code should be like: (never really try it in code, you can follow this concept doing the experiment)

final isInViewport = _offsetToRevealInViewport(10, 0) => 0 && _offsetToRevealInViewport(10, 0) <= 0;

[LinXunFeng]

The flutter_scrollview_observer package can help you.

ListViewObserver(
  child: _buildListView(),
  onObserve: (resultModel) {
    print('firstChild.index -- ${resultModel.firstChild?.index}');
    print('displaying -- ${resultModel.displayingChildIndexList}');
  },
)