main.dart

main.dart

import 'package:flutter/material.dart';
import 'package:flutter/gestures.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Scroll Performance',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  List words = [
    "This",
    "class",
    "is",
    "the ",
    "configuration ",
    "for ",
    "the ",
    "state. ",
    "It ",
    "holds ",
    "the ",
    "values ",
    "(",
    "in ",
    "this",
    "case",
    "the ",
    "title",
    ")",
    " provided",
    " by",
    " the",
    " parent",
    " (",
    "in",
    " this",
    " case",
    " the",
    " App",
    " widget",
    ")",
    ".",
    "\n"
  ];

  @override
  initState() {
    super.initState();
    words = List.from(words)..addAll(words);
    words = List.from(words)..addAll(words);
    words = List.from(words)..addAll(words);
    words = List.from(words)..addAll(words);
    words = List.from(words)..addAll(words);
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: SingleChildScrollView(child: ArticleRichText(words: words)),
      // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class ArticleRichText extends StatefulWidget {
  ArticleRichText({Key key, @required this.words}) : super(key: key);
  final List words;

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

class ArticleRichTextState extends State<ArticleRichText> {
  MultiTapGestureRecognizer _getTapRecognizer(String word) {
    if (word == "") return null;
    return MultiTapGestureRecognizer()
      ..longTapDelay = Duration(milliseconds: 400)
      ..onLongTapDown = (i, detail) {
        print("onLongTapDown");
      }
      ..onTap = (i) {
        print("onTap");
      };
  }

  bool hasLetter(String str) {
    RegExp regHasLetter = new RegExp(r"[a-zA-Z]+");
    return regHasLetter.hasMatch(str);
  }

  TextSpan getTextSpan(String word) {
    return TextSpan(
        style: TextStyle(color: Colors.black87, fontFamily: "NotoSans-Medium", fontSize: 20),
        text: hasLetter(word) ? " " : "",
        children: [
          hasLetter(word)
              ? TextSpan(text: word, recognizer: _getTapRecognizer(word))
              : TextSpan(text: word),
          word == "\n" ? TextSpan(text: "   ") : TextSpan(text: "")
        ]);
  }

  @override
  Widget build(BuildContext context) {
    return RichText(
      text: TextSpan(
        text: '   ',
        children: widget.words.map((d) {
          return getTextSpan(d);
        }).toList(),
      ),
    );
  }
}