如何在 flutter 中将列表视图滚动到底部

Question

I have a flutter app contain a list view builder (chat page) I need to scroll the page to the end of the page to the last message?

Answer 1

You will need to create a scrollController and pass that to the ListView and run a code like this:

class SampleList extends StatefulWidget {
  @override
  _SampleListState createState() => _SampleListState();
}

class _SampleListState extends State<SampleList> {
  ScrollController _scrollController;
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      controller: _scrollController,
      itemBuilder: (_, index) => ListTile(
        title: Text(
          index.toString(),
        ),
      ),
    );
  }

  void scrollToBottom() {
    final bottomOffset = _scrollController.position.maxScrollExtent;
    _scrollController.animateTo(
      bottomOffset,
      duration: Duration(milliseconds: 1000),
      curve: Curves.easeInOut,
    );
  }

  @override
  void initState() {
    _scrollController = ScrollController();
    super.initState();
  }

  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }
}

Answer 2

Setting reverse: true to ListView widget will bring the newest element at the bottom. With this, you can achieve a chat timeline easily.

ListView.builder(
  reverse: true,
  itemBuilder: (context, index) => _chatCell(),
)

Answer 3

Initialize the object of ScrollController class in the initState method.

Remember:- 1) Call the super.initState(); at the top of the initState method. 2) ListView should be connected with the scroll controller's object.

WidgetsBinding.instance.addPostFrameCallback((_) { scrollController.jumpTo(scrollController.position.maxScrollExtent); });

Then, add the above code at the top of the build method. It will scroll automatically to the bottom of the list view of messages.

Answer 4

Perfect way to do this is by adding

reverse: true

to the ListView.builder() and change the way you give data the list view. Like this.

Instead of retrieving normally, reverse it and give it to the list view builder.

<List> _messages = [...];
_messages.reversed.toList();