当文本在 Flutter 中溢出时，如何使文本小部件像跑马灯一样

Question

我正在寻找一种在文本小部件上实现选取框样式的方法，以便当文本溢出屏幕时它会自动开始滚动。有没有办法做到这一点。我已经尝试了所有的装饰模式，但似乎无法在那里找到 Marquee 选项。

Answer 1

这个小部件是我想出来的，我认为它可以满足您的需求：

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(
      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,
        );
      }
    }
  }
}

它的功能应该是很明显的。示例实现如下所示：

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"),
          ),
        ),
      ),
    );
  }
}

Answer 2

您可以使用 marquee 包

marquee 无限滚动文本的小部件。提供许多自定义设置，包括自定义滚动方向、持续时间、曲线以及每轮后的暂停。

使用 pubspec.yaml 文件中添加的 marquee 依赖项

dependencies:
  marquee: ^2.1.0

要将依赖项导入您的文件，请使用以下代码行：

import 'package:marquee/marquee.dart';

你可以像这样使用它，这很简单，没有任何参数属性

    Marquee(
      text: 'There once was a boy who told this story about a boy',
    )

您还可以使用如下所示的一些属性和可定制性

Marquee(
  text: 'Some sample text that takes some space.',
  style: TextStyle(fontWeight: FontWeight.bold),
  scrollAxis: Axis.horizontal,
  crossAxisAlignment: CrossAxisAlignment.start,
  blankSpace: 20.0,
  velocity: 100.0,
  pauseAfterRound: Duration(seconds: 1),
  startPadding: 10.0,
  accelerationDuration: Duration(seconds: 1),
  accelerationCurve: Curves.linear,
  decelerationDuration: Duration(milliseconds: 500),
  decelerationCurve: Curves.easeOut,
)

Answer 3

使用 Marquee 包。如果您收到任何 'hasSize' 错误或 'Incorrect uses of Parent Widget' 错误..

只需用容器包裹 Marquee 小部件并给出该容器的高度和宽度。

当文本在 Flutter 中溢出时，如何使文本小部件像跑马灯一样

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