clear toast on tap

this adds a generator showDismissibleSnackBar which by default allows
tapping to clear snack bar toasts. all SnackBar properties are still
available and the

all callers should now use showDismissibleSnackBar() instead of calling
ScaffoldMessenger.of(context).showSnackBar(SnackBar())

lib/helpers/link_handler.dart

@@ -3,6 +3,7 @@ import 'package:flutter_linkify/flutter_linkify.dart';
 import 'package:url_launcher/url_launcher.dart';
 import '../l10n/l10n.dart';
 import '../utils/platform_info.dart';
+import '../helpers/snack_bar_builder.dart';
 
 class LinkHandler {
   static TextStyle defaultLinkStyle(BuildContext context, TextStyle base) {
@@ -93,21 +94,19 @@ class LinkHandler {
       final uri = Uri.parse(url);
       if (!await launchUrl(uri, mode: LaunchMode.externalApplication)) {
         if (context.mounted) {
-          ScaffoldMessenger.of(context).showSnackBar(
-            SnackBar(
-              content: Text(context.l10n.chat_couldNotOpenLink(url)),
-              backgroundColor: Colors.red,
-            ),
+          showDismissibleSnackBar(
+            context,
+            content: Text(context.l10n.chat_couldNotOpenLink(url)),
+            backgroundColor: Colors.red,
           );
         }
       }
     } catch (e) {
       if (context.mounted) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(
-            content: Text(context.l10n.chat_invalidLink),
-            backgroundColor: Colors.red,
-          ),
+        showDismissibleSnackBar(
+          context,
+          content: Text(context.l10n.chat_invalidLink),
+          backgroundColor: Colors.red,
         );
       }
     }

lib/helpers/snack_bar_builder.dart

@@ -0,0 +1,56 @@
+import 'package:flutter/material.dart';
+
+// showDismissibleSnackBar shows  a [SnackBar] with tap to dismiss
+// all other properties are default and optional
+void showDismissibleSnackBar(
+  BuildContext context, {
+  Key? key,
+  required Widget content,
+  Color? backgroundColor,
+  double? elevation,
+  EdgeInsetsGeometry? margin,
+  EdgeInsetsGeometry? padding,
+  double? width,
+  ShapeBorder? shape,
+  HitTestBehavior? hitTestBehavior,
+  SnackBarBehavior? behavior,
+  SnackBarAction? action,
+  double? actionOverflowThreshold,
+  bool? showCloseIcon,
+  Color? closeIconColor,
+  Duration? duration,
+  bool? persist,
+  Animation<double>? animation,
+  void Function()? onVisible,
+  DismissDirection? dismissDirection,
+  Clip? clipBehavior,
+}) {
+  final messenger = ScaffoldMessenger.of(context);
+  messenger.showSnackBar(
+    SnackBar(
+      key: key,
+      content: GestureDetector(
+        onTap: () => messenger.hideCurrentSnackBar(),
+        child: content,
+      ),
+      backgroundColor: backgroundColor,
+      elevation: elevation,
+      margin: margin,
+      padding: padding,
+      width: width,
+      shape: shape,
+      hitTestBehavior: hitTestBehavior,
+      behavior: behavior,
+      action: action,
+      actionOverflowThreshold: actionOverflowThreshold,
+      showCloseIcon: showCloseIcon,
+      closeIconColor: closeIconColor,
+      duration: duration ?? const Duration(seconds: 4),
+      persist: persist,
+      animation: animation,
+      onVisible: onVisible,
+      dismissDirection: dismissDirection ?? DismissDirection.down,
+      clipBehavior: clipBehavior ?? Clip.hardEdge,
+    ),
+  );
+}