flutter ListView scroll to index not available

Question

What I needed:

I want to scroll a list by some index, how can i do that.

What I know:

scrollToIndex should start from n index, but how can we scroll to any index?

Answer 1

Unfortunately, ListView has no built-in approach to a scrollToIndex() function. You’ll have to develop your own way to measure to that element’s offset for animateTo() or jumpTo(), or you can search through these suggested solutions/plugins or from other posts like Flutter: Scrolling to a widget in ListView

(the general scrollToIndex issue is discussed at flutter/issues/12319 since 2017, but still with no current plans)

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But there is a different kind of ListView that does support scrollToIndex (as mentioned by Slashbin):

• ScrollablePositionedList
  • dependency: scrollable_positioned_list

You set it up exactly like ListView and works the same, except you now have access to a ItemScrollController that does:

• jumpTo({index, alignment})
• scrollTo({index, alignment, duration, curve})

Simplified example:

ItemScrollController _scrollController = ItemScrollController();  ScrollablePositionedList.builder(   itemScrollController: _scrollController,   itemCount: _myList.length,   itemBuilder: (context, index) {     return _myList[index];   }, )  _scrollController.scrollTo(index: 150, duration: Duration(seconds: 1)); 

(note that this library is developed by Google but not by the core Flutter team.)

Answer 2

ScrollablePositionedList can be used for this. https://github.com/google/flutter.widgets/tree/master/packages/scrollable_positioned_list

Pub link - https://pub.dev/packages/scrollable_positioned_list

final ItemScrollController itemScrollController = ItemScrollController(); final ItemPositionsListener itemPositionListener = ItemPositionsListener.create(); 

ScrollablePositionedList.builder(   itemCount: 500,   itemBuilder: (context, index) => Text('Item $index'),   itemScrollController: itemScrollController,   itemPositionsListener: itemPositionListener, ); 

One then can scroll to a particular item with:

itemScrollController.scrollTo(   index: 150,   duration: Duration(seconds: 2),   curve: Curves.easeInOutCubic);