fix: Better authwebview

lib/views/auth_web_view.dart

@@ -6,17 +6,23 @@ import 'package:flutter_gen/gen_l10n/l10n.dart';
 import 'package:url_launcher/url_launcher.dart';
 import 'package:webview_flutter/webview_flutter.dart';
 
-class AuthWebView extends StatelessWidget {
+class AuthWebView extends StatefulWidget {
   final String authType;
   final String session;
   final Function onAuthDone;
 
   const AuthWebView(this.authType, this.session, this.onAuthDone);
 
+  @override
+  _AuthWebViewState createState() => _AuthWebViewState();
+}
+
+class _AuthWebViewState extends State<AuthWebView> {
+  bool _isLoading = true;
   @override
   Widget build(BuildContext context) {
     final url = Matrix.of(context).client.homeserver.toString() +
-        '/_matrix/client/r0/auth/$authType/fallback/web?session=$session';
+        '/_matrix/client/r0/auth/${widget.authType}/fallback/web?session=${widget.session}';
     if (kIsWeb) launch(url);
     return Scaffold(
       appBar: AppBar(
@@ -25,17 +31,18 @@ class AuthWebView extends StatelessWidget {
           icon: Icon(Icons.close),
           onPressed: () {
             AdaptivePageLayout.of(context).pop();
-            onAuthDone();
+            widget.onAuthDone();
           },
         ),
       ),
       body: Column(
         children: <Widget>[
-          LinearProgressIndicator(),
+          if (_isLoading) LinearProgressIndicator(),
           Expanded(
             child: kIsWeb
                 ? Center(child: Icon(Icons.link_outlined))
                 : WebView(
+                    onPageFinished: (_) => setState(() => _isLoading = false),
                     initialUrl: url,
                     javascriptMode: JavascriptMode.unrestricted,
                   ),

lib/views/sign_up_password.dart

@@ -68,6 +68,7 @@ class _SignUpPasswordState extends State<SignUpPassword> {
           );
         } else {
           if (_lastAuthWebViewStage == currentStage) {
+            _lastAuthWebViewStage = null;
             setState(
                 () => passwordError = L10n.of(context).oopsSomethingWentWrong);
             return setState(() => loading = false);