WebView в ScrollView (автоматизированный c прокрутка) - PullRequest
Новая
       18

WebView в ScrollView (автоматизированный c прокрутка)

0 голосов
/ 28 февраля 2020

Я разрабатываю приложение для музыкантов. Основным функционалом является автоматическая c прокрутка экрана (текст песни). У меня все содержимое в HTML, поэтому мне нужно использовать виджет WebView. Моя проблема в том, что я не могу сделать автоматическую прокрутку c. Я пытаюсь использовать SingleChildScrollView, как показано в коде ниже.

Используя WebView, я всегда получаю пустой экран. Когда я использую текстовую переменную, все работает нормально. 

import 'package:scroll/models/song.dart';
import 'package:flutter/material.dart';
import 'package:scroll/global.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:http/http.dart' as http;
import 'dart:async';
import 'dart:convert';

import 'package:webview_flutter/webview_flutter.dart';

List<Song> _songLines = [];
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  ScrollController _scrollController = ScrollController();
  bool scroll = false;
  int speedFactor = 20;

  int userId = 0;
  // Get json result and convert it to model. Then add
  Future<Null> getDetails() async {
    var _sharedPreferences = await SharedPreferences.getInstance();
    userId = _sharedPreferences.getInt('USERID') ?? 0;
    final String url = '$URL_SONGS/readOne.php?id=${562}'; // prov

    final mapResponse = await http.get(url);
    final responseJson = json.decode(mapResponse.body);

    setState(() {
      if (responseJson["result"] == "ok") {
        for (Map song in responseJson["data"]) {
          _songLines.add(Song.fromJson(song));
        }
      }
    });
  }

  _scroll() {
    double maxExtent = _scrollController.position.maxScrollExtent;
    double distanceDifference = maxExtent - _scrollController.offset;
    double durationDouble = distanceDifference / speedFactor;

    _scrollController.animateTo(_scrollController.position.maxScrollExtent,
        duration: Duration(seconds: durationDouble.toInt()),
        curve: Curves.linear);
  }

  _toggleScrolling() {
    setState(() {
      scroll = !scroll;
    });

    if (scroll) {
      _scroll();
    } else {
      _scrollController.animateTo(_scrollController.offset,
          duration: Duration(seconds: 1), curve: Curves.linear);
    }
  }

  @override
  Widget build(BuildContext context) {
    String val = '''
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE.BUNCH OF TEXT HERE. BUNCH OF TEXT HERE.v 
''';
    return Scaffold(
      appBar: AppBar(
        title: Text('Lyrics'),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.arrow_back),
            onPressed: () {
              speedFactor -= 20;
              _scroll();
            },
          ),
          IconButton(
            icon: Icon(Icons.arrow_forward),
            onPressed: () {
              speedFactor += 20;
              _scroll();
            },
          ),
        ],
      ),
      body: NotificationListener(
        onNotification: (notif) {
          if (notif is ScrollEndNotification && scroll) {
            Timer(Duration(seconds: 1), () {
              _scroll();
            });
          }
          return true;
        },
        child: SingleChildScrollView(
          child: PrimaryScrollController(
            controller: _scrollController,
            child: WebviewWiget(),
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(onPressed: () {
        _toggleScrolling();
      }), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class WebviewWiget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    print("Build WebviewWiget");
    return Container(
      constraints: BoxConstraints(maxHeight: 500),
      child: WebView(
        initialUrl: "https://en.wikipedia.org/wiki/Flutter_(software)/",
      ),
    );
  }
}
...