[url_launcher] Add a workaround for Uri encoding

packages/url_launcher/url_launcher/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 6.0.7
+
+* Update the README to describe a workaround to the `Uri` query
+  encoding bug.
+
 ## 6.0.6
 
 * Require `url_launcher_platform_interface` 2.0.3. This fixes an issue

packages/url_launcher/url_launcher/README.md

@@ -10,10 +10,10 @@ To use this plugin, add `url_launcher` as a [dependency in your pubspec.yaml fil
 
 ## Installation
 
-### iOS 
+### iOS
 Add any URL schemes passed to `canLaunch` as `LSApplicationQueriesSchemes` entries in your Info.plist file.
 
-Example:  
+Example:
 ```
 <key>LSApplicationQueriesSchemes</key>
 <array>
@@ -73,25 +73,35 @@ apps installed, so can't open `tel:` or `mailto:` links.
 
 ### Encoding URLs
 
-URLs must be properly encoded, especially when including spaces or other special characters. This can be done using the [`Uri` class](https://api.dart.dev/stable/2.7.1/dart-core/Uri-class.html):
+URLs must be properly encoded, especially when including spaces or other special
+characters. This can be done using the
+[`Uri` class](https://api.dart.dev/stable/2.7.1/dart-core/Uri-class.html).
+For example:
 ```dart
-import 'dart:core';
-import 'package:url_launcher/url_launcher.dart';
+String? encodeQueryParameters(Map<String, String> params) {
+  return params.entries
+      .map((e) => '${Uri.encodeComponent(e.key)}=${Uri.encodeComponent(e.value)}')
+      .join('&');
+}
 
-final Uri _emailLaunchUri = Uri(
+final Uri emailLaunchUri = Uri(
   scheme: 'mailto',
   path: '[email protected]',
-  queryParameters: {
+  query: encodeQueryParameters(<String, String>{
     'subject': 'Example Subject & Symbols are allowed!'
-  }
+  }),
 );
 
-// ...
-
-// mailto:[email protected]?subject=Example+Subject+%26+Symbols+are+allowed%21
-launch(_emailLaunchUri.toString());
+launch(emailLaunchUri.toString());
 ```
 
+**Warning**: For any scheme other than `http` or `https`, you should use the
+`query` parameter and the `encodeQueryParameters` function shown above rather
+than `Uri`'s `queryParameters` constructor argument, due to
+[a bug](https://github.com/dart-lang/sdk/issues/43838) in the way `Uri`
+encodes query parameters. Using `queryParameters` will result in spaces being
+converted to `+` in many cases.
+
 ## Handling missing URL receivers
 
 A particular mobile device may not be able to receive all supported URL schemes.
@@ -113,4 +123,4 @@ By default, Android opens up a browser when handling URLs. You can pass
 If you do this for a URL of a page containing JavaScript, make sure to pass in
 `enableJavaScript: true`, or else the launch method will not work properly. On
 iOS, the default behavior is to open all web URLs within the app. Everything
-else is redirected to the app handler.
+else is redirected to the app handler.

packages/url_launcher/url_launcher/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for launching a URL. Supports
   web, phone, SMS, and email schemes.
 repository: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 6.0.6
+version: 6.0.7
 
 environment:
   sdk: ">=2.12.0 <3.0.0"