flutter - 在flutter中下拉刷新WebView页面

Question

我用 WebView 创建了一个 flutter 应用程序

有什么办法可以扫一扫刷新网页

我正在使用“webview_flutter_plugin”插件

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: Stack(
        children: <Widget>[
          Container(
            child: Center(
              child: Text(_title),
            ),
          ),
        ],
      )),
      body: SafeArea(
          child: WebView(
              key: _key,
              javascriptMode: JavascriptMode.unrestricted,
              initialUrl: _url)),
    );
  }
}

Answer 1

解决起来并不容易，但您可以尝试这种方式。

import 'dart:io';
import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:fluttertoast/fluttertoast.dart';

int scheck;
WebViewController controllerGlobal;
void main() {
  WidgetsFlutterBinding.ensureInitialized();
  SystemChrome.setEnabledSystemUIOverlays([]);
  runApp(
    new MaterialApp(
      debugShowCheckedModeBanner: false,
      home: new WebViewEx(),
    ),
  );
}

class WebViewEx extends StatefulWidget {
  @override
  WebViewExampleState createState() => WebViewExampleState();
}

class WebViewExampleState extends State<WebViewEx> {
  bool check, check1;
  ScrollController _scrollController;
  @override
  void initState() {
    _scrollController = ScrollController();
    _scrollController.addListener(_scrollListener);
    super.initState();
    check = false;
    check1 = false;
  }

  _scrollListener() {
    if (_scrollController.offset <=
            _scrollController.position.minScrollExtent &&
        !_scrollController.position.outOfRange) {
      controllerGlobal.reload();
    }
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () => controllerGlobal.goBack(),
      child: ListView(
        physics: ClampingScrollPhysics(),
        shrinkWrap: true,
        children: [
          Container(
            padding: EdgeInsets.all(10),
            height: MediaQuery.of(context).size.height,
            child: WebView(
              initialUrl: '...............',
              gestureNavigationEnabled: true,
              debuggingEnabled: true,
              gestureRecognizers: [
                Factory(() => PlatformViewVerticalGestureRecognizer()),
              ].toSet(),
              javascriptMode: JavascriptMode.unrestricted,
              onPageFinished: (String url) {
                setState(() {
                  bool temp = check;
                  check = true;
                  if (!temp) controllerGlobal.scrollBy(0, 10);
                });
              },
              onWebViewCreated: (WebViewController webViewController) {
                controllerGlobal = webViewController;
              },
            ),
          ),
        ],
      ),
    );
  }

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

class PlatformViewVerticalGestureRecognizer
    extends VerticalDragGestureRecognizer {
  PlatformViewVerticalGestureRecognizer({PointerDeviceKind kind})
      : super(kind: kind);

  Offset _dragDistance = Offset.zero;

  @override
  void addPointer(PointerEvent event) {
    startTrackingPointer(event.pointer);
  }

  @override
  void handleEvent(PointerEvent event) {
    _dragDistance = _dragDistance + event.delta;
    controllerGlobal.getScrollY().then((value) {
      print(value);
      if (value < 5) {
        Fluttertoast.showToast(
            msg: "RELOADING",
            toastLength: Toast.LENGTH_SHORT,
            gravity: ToastGravity.BOTTOM,
            timeInSecForIosWeb: 1,
            backgroundColor: Colors.amber[800],
            textColor: Colors.black,
            fontSize: 16.0);
        controllerGlobal.reload();
      }
    });
    // if (event is PointerMoveEvent) {
    //   final double dy = _dragDistance.dy.abs();
    //   final double dx = _dragDistance.dx.abs();

    //   if (dy > dx && dy > kTouchSlop) {
    //     // vertical drag - accept
    //     resolve(GestureDisposition.accepted);
    //     _dragDistance = Offset.zero;
    //   } else if (dx > kTouchSlop && dx > dy) {
    //     // horizontal drag - stop tracking
    //     stopTrackingPointer(event.pointer);
    //     _dragDistance = Offset.zero;
    //   }
    // }
  }

  @override
  String get debugDescription => 'horizontal drag (platform view)';

  @override
  void didStopTrackingLastPointer(int pointer) {}
}