Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.1k views
in Technique[技术] by (71.8m points)

dart - flutter ListView scroll to index not available

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?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

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)


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

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.)


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...