Question

如果用户没有互联网，我想在WebView应用程序中更改“网页不可用”。

我阅读了文档，然后尝试了另外一些puglins

import 'package:webview_flutter/webview_flutter.dart';
[...]
class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: const WebView(
        initialUrl: 'https://google.com',
        javascriptMode: JavascriptMode.unrestricted,
      ),
    );
  }
}

Answer 1

您可以尝试使用我的插件flutter_inappwebview。在WebView加载URL（onLoadError事件）以及接收HTTP错误（例如403、404等）（onLoadHttpError事件）时，它具有管理错误的事件。

带有工作代码的完整示例，如果用户没有互联网连接，该示例将加载自定义错误页面：

import 'dart:async';

import 'package:flutter/material.dart';

import 'package:flutter_inappwebview/flutter_inappwebview.dart';

Future main() async {
  runApp(new MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> {

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: InAppWebViewPage()
    );
  }
}

class InAppWebViewPage extends StatefulWidget {
  @override
  _InAppWebViewPageState createState() => new _InAppWebViewPageState();
}

class _InAppWebViewPageState extends State<InAppWebViewPage> {
  InAppWebViewController webView;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
            title: Text("InAppWebView")
        ),
        body: Container(
            child: Column(children: <Widget>[
              Expanded(
                child: Container(
                  child: InAppWebView(
                    initialUrl: "https://flutter.dev/",
                    initialHeaders: {},
                    initialOptions: InAppWebViewWidgetOptions(
                        inAppWebViewOptions: InAppWebViewOptions(
                          debuggingEnabled: true,
                        ),
                    ),
                    onWebViewCreated: (InAppWebViewController controller) {
                      webView = controller;
                    },
                    onLoadStart: (InAppWebViewController controller, String url) {

                    },
                    onLoadStop: (InAppWebViewController controller, String url) {

                    },
                    onLoadError: (InAppWebViewController controller, String url, int code, String message) async {
                      print("error $url: $code, $message");

                      var tRexHtml = await controller.getTRexRunnerHtml();
                      var tRexCss = await controller.getTRexRunnerCss();

                      controller.loadData(data: """
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0,maximum-scale=1.0, user-scalable=no">
    <style>$tRexCss</style>
  </head>
  <body>
    $tRexHtml
    <p>
      URL $url failed to load.
    </p>
    <p>
      Error: $code, $message
    </p>
  </body>
</html>
                  """);
                    },
                    onLoadHttpError: (InAppWebViewController controller, String url, int statusCode, String description) async {
                      print("HTTP error $url: $statusCode, $description");
                    },
                  ),
                ),
              ),
            ]))
    );
  }
}

结果是：

此示例直接加载html源，但是您可以从资产文件夹或url加载html文件。

只是为了好玩：我的插件包含Google Chrome t-rex游戏的javascript和CSS代码！

Flutter Webview更改网页不可用

1 个答案: