Results the preview

1 Basic use code

void main() {
    
  /// Start the root directory 
  runApp(MaterialApp(
    home: TestTipsPage(),
  ));
}

class TestTipsPage extends StatefulWidget {
    
  @override
  _TestTipsPageState createState() => _TestTipsPageState();
}

class _TestTipsPageState extends State<TestTipsPage> {
    
  @override
  void initState() {
    
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: Container(
          alignment: Alignment.center,
          width: double.infinity,
          height: 24,
          child: buildMarqueeWidget(),
        ),
      ),
    );
  }
 }

2 Core use code

  MarqueeWidget buildMarqueeWidget(List<String> loopList) {
    
    /// Rotate up and down   Safety tips 
    return MarqueeWidget(
      // Son Item Builder 
      itemBuilder: (BuildContext context, int index) {
    
        String itemStr = loopList[index];
        // It can usually be a  Text Text 
        return Text(itemStr);
      },
      // Number of circular prompt messages 
      count: loopList.length,
    );
  }

3 Core implementation code

import 'dart:async';
import 'package:flutter/cupertino.dart';

//  News rotation rolling up and down 
class MarqueeWidget extends StatefulWidget {
    
  ///  Number of subviews 
  final int count; 
  /// Subview builder 
  final IndexedWidgetBuilder itemBuilder;
  /// Time interval of rotation 
  final int loopSeconds;

  const MarqueeWidget({
    
    Key? key,
    required this.count,
    required this.itemBuilder,
    this.loopSeconds = 5,
  }) : super(key: key); 

  @override
  _MarqueeWidgetState createState() => _MarqueeWidgetState();
}

class _MarqueeWidgetState extends State<MarqueeWidget> {
    
  late PageController _controller;
  late Timer _timer;

  @override
  void initState() {
    
    super.initState();
    _controller = PageController();
    _timer = Timer.periodic(Duration(seconds: widget.loopSeconds), (timer) {
    
      if (_controller.page != null) {
    
        //  If you are currently on the last page , Then jump directly to the first page , The two contents are the same , There is no visual perception when jumping 
        if (_controller.page!.round() >= widget.count) {
    
          _controller.jumpToPage(0);
        }
        _controller.nextPage(
            duration: const Duration(seconds: 1), curve: Curves.linear);
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    
    return PageView.builder(
      scrollDirection: Axis.vertical,
      controller: _controller,
      itemBuilder: (buildContext, index) {
    
        if (index < widget.count) {
    
          return widget.itemBuilder(buildContext, index);
        } else {
    
          return widget.itemBuilder(buildContext, 0);
        }
      },
      itemCount: widget.count + 1, 
    );
  }

  @override
  void dispose() {
    
    super.dispose();
    _controller.dispose();
    _timer.cancel();
  }
}