How to make a Text widget act like marquee when the text overflows in Flutter

Question

I'm looking for a way to implement Marquee style on a Text widget so that it automatically start scrolling when the text is overflowed from the screen. Is there a way to do it. I've tried all the decoration modes but cant seem to find a Marquee option there.

Answer 1

This widget is what I came up with, and I think it serves your needs:

class MarqueeWidget extends StatefulWidget {
  final Widget child;
  final Axis direction;
  final Duration animationDuration, backDuration, pauseDuration;

  const MarqueeWidget({
    Key? key,
    required this.child,
    this.direction = Axis.horizontal,
    this.animationDuration = const Duration(milliseconds: 6000),
    this.backDuration = const Duration(milliseconds: 800),
    this.pauseDuration = const Duration(milliseconds: 800),
  }) : super(key: key);

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

class _MarqueeWidgetState extends State<MarqueeWidget> {
  late ScrollController scrollController;

  @override
  void initState() {
    scrollController = ScrollController(initialScrollOffset: 50.0);
    WidgetsBinding.instance.addPostFrameCallback(scroll);
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      physics: NeverScrollableScrollPhysics(),
      child: widget.child,
      scrollDirection: widget.direction,
      controller: scrollController,
    );
  }

  void scroll(_) async {
    while (scrollController.hasClients) {
      await Future.delayed(widget.pauseDuration);
      if (scrollController.hasClients) {
        await scrollController.animateTo(
          scrollController.position.maxScrollExtent,
          duration: widget.animationDuration,
          curve: Curves.ease,
        );
      }
      await Future.delayed(widget.pauseDuration);
      if (scrollController.hasClients) {
        await scrollController.animateTo(
          0.0,
          duration: widget.backDuration,
          curve: Curves.easeOut,
        );
      }
    }
  }
}

Its functionality should be pretty obvious. An example implementation would look like this:

class FlutterMarqueeText extends StatefulWidget {
  const FlutterMarqueeText({Key? key}) : super(key: key);

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

class _FlutterMarqueeTextState extends State<FlutterMarqueeText> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Flutter Marquee Text"),
      ),
      body: const Center(
        child: SizedBox(
          width: 200.0,
          child: MarqueeWidget(
            direction: Axis.horizontal,
            child: Text("This text is to long to be shown in just one line"),
          ),
        ),
      ),
    );
  }
}