我的方法是首先指定一个FocusNode并将其分配给消息发送方TextField。我会调整聊天室的initState方法：

@override
  void initState() {
    super.initState();
    // After the widget has been built 
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _focusNode.addListener(() async {
        if (_focusNode.hasFocus) {
          // If you remove the delay sometimes the scroll doesnt animate completely at the end
          await Future.delayed(const Duration(milliseconds: 150));
          _controller.animateTo(
            _controller.position.maxScrollExtent,
            duration: const Duration(milliseconds: 700),
            curve: Curves.easeOut,
          );
        }
      });
      // This is if you want to automatically toggle the keyboard when visitting the screen
      _focusNode.requestFocus();
    });
  }

这样，当您点击TextField时，无论您在哪里，消息都会在底部滚动。
我使用的整个示例代码：

class ChatRoom extends StatefulWidget {
  const ChatRoom({super.key});

  @override
  State<ChatRoom> createState() => _ChatRoomState();
}

class _ChatRoomState extends State<ChatRoom> {
  ScrollController _controller = ScrollController();
  FocusNode _focusNode = FocusNode();

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _focusNode.addListener(() async {
        if (_focusNode.hasFocus) {
          // If you remove the delay sometimes the scroll doesnt animate completely at the end
          await Future.delayed(const Duration(milliseconds: 150));
          _controller.animateTo(
            _controller.position.maxScrollExtent,
            duration: const Duration(milliseconds: 700),
            curve: Curves.easeOut,
          );
        }
      });
      _focusNode.requestFocus();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
            onPressed: () {
              Navigator.pop(context);
            },
            icon: const Icon(Icons.arrow_back)),
        elevation: 0,
        centerTitle: true,
        title: Text(
          'chat name',
          overflow: TextOverflow.ellipsis,
        ),
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.separated(
              controller: _controller,
              physics: const BouncingScrollPhysics(),
              itemBuilder: (context, index) {
                return Column(children: [
                  SizedBox(
                    width: 200,
                    height: 100,
                    child: Text('text $index'),
                  ),
                ]);
              },
              separatorBuilder: (context, index) => const SizedBox(height: 5.0),
              itemCount: 35,
            ),
          ),
          TextField(
            focusNode: _focusNode,
            decoration: InputDecoration(
              hintText: 'Type a message',
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(50),
              ),
              suffixIcon: IconButton(
                onPressed: () {},
                icon: const Icon(Icons.send),
              ),
            ),
          ),
        ],
      ),
    );
  }
}