diff --git a/app/lib/pages/home_page.dart b/app/lib/pages/home_page.dart
index 60383e94..2c945bcc 100644
--- a/app/lib/pages/home_page.dart
+++ b/app/lib/pages/home_page.dart
@@ -6,6 +6,7 @@ import 'package:flutter_quill/models/documents/document.dart';
 import 'package:flutter_quill/widgets/controller.dart';
 import 'package:flutter_quill/widgets/editor.dart';
 import 'package:flutter_quill/widgets/toolbar.dart';
+import 'package:url_launcher/url_launcher.dart';
 
 class HomePage extends StatefulWidget {
   @override
@@ -78,10 +79,17 @@ class _HomePageState extends State<HomePage> {
               enableInteractiveSelection: true,
               expands: false,
               padding: EdgeInsets.zero,
+              onLaunchUrl: _launchUrl,
             ),
           ),
         ),
       ],
     );
   }
+
+  void _launchUrl(String url) async {
+    if (await canLaunch(url)) {
+      await launch(url);
+    }
+  }
 }
diff --git a/app/pubspec.lock b/app/pubspec.lock
index 86094d48..4c85745c 100644
--- a/app/pubspec.lock
+++ b/app/pubspec.lock
@@ -74,6 +74,11 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   matcher:
     dependency: transitive
     description:
@@ -95,6 +100,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.0-nullsafety.1"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.3"
   quill_delta:
     dependency: transitive
     description:
@@ -177,6 +189,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.3.0-nullsafety.3"
+  url_launcher:
+    dependency: "direct main"
+    description:
+      name: url_launcher
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.7.10"
+  url_launcher_linux:
+    dependency: transitive
+    description:
+      name: url_launcher_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+4"
+  url_launcher_macos:
+    dependency: transitive
+    description:
+      name: url_launcher_macos
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+9"
+  url_launcher_platform_interface:
+    dependency: transitive
+    description:
+      name: url_launcher_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.9"
+  url_launcher_web:
+    dependency: transitive
+    description:
+      name: url_launcher_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.5+1"
+  url_launcher_windows:
+    dependency: transitive
+    description:
+      name: url_launcher_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+3"
   vector_math:
     dependency: transitive
     description:
@@ -186,4 +240,4 @@ packages:
     version: "2.1.0-nullsafety.3"
 sdks:
   dart: ">=2.10.0-110 <2.11.0"
-  flutter: ">=1.17.0 <2.0.0"
+  flutter: ">=1.22.0 <2.0.0"
diff --git a/app/pubspec.yaml b/app/pubspec.yaml
index 3a6814e0..ed06341d 100644
--- a/app/pubspec.yaml
+++ b/app/pubspec.yaml
@@ -23,6 +23,7 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  url_launcher: ^5.7.10
 
 
   # The following adds the Cupertino Icons font to your application.
diff --git a/lib/widgets/editor.dart b/lib/widgets/editor.dart
index f37360d0..746d207c 100644
--- a/lib/widgets/editor.dart
+++ b/lib/widgets/editor.dart
@@ -22,6 +22,9 @@ import 'cursor.dart';
 import 'default_styles.dart';
 import 'delegate.dart';
 
+const urlPattern =
+    r"^((https?|http)://)?([-A-Z0-9.]+)(/[-A-Z0-9+&@#/%=~_|!:,.;]*)?(\?[A-Z0-9+&@#/%=~_|!:‌​,.;]*)?$";
+
 abstract class EditorState extends State<RawEditor> {
   TextEditingValue getTextEditingValue();
 
@@ -252,6 +255,8 @@ class _QuillEditorState extends State<QuillEditor>
 
 class _QuillEditorSelectionGestureDetectorBuilder
     extends EditorTextSelectionGestureDetectorBuilder {
+  static final urlRegExp = new RegExp(urlPattern, caseSensitive: false);
+
   final _QuillEditorState _state;
 
   _QuillEditorSelectionGestureDetectorBuilder(this._state) : super(_state);
@@ -313,10 +318,11 @@ class _QuillEditorSelectionGestureDetectorBuilder
     Leaf segment = segmentResult.node as Leaf;
     if (segment.style.containsKey(Attribute.link.key) &&
         getEditor().widget.onLaunchUrl != null) {
-      if (getEditor().widget.readOnly) {
-        getEditor()
-            .widget
-            .onLaunchUrl(segment.style.attributes[Attribute.link.key].value);
+      String link = segment.style.attributes[Attribute.link.key].value;
+      if (getEditor().widget.readOnly &&
+          link != null &&
+          urlRegExp.firstMatch(link) != null) {
+        getEditor().widget.onLaunchUrl(link);
       }
     }
   }
diff --git a/lib/widgets/text_block.dart b/lib/widgets/text_block.dart
index 32507f6a..21301579 100644
--- a/lib/widgets/text_block.dart
+++ b/lib/widgets/text_block.dart
@@ -596,7 +596,7 @@ class _NumberPoint extends StatelessWidget {
     }
     if (this.indentLevelCounts.containsKey(level + 1)) {
       // last visited level is done, going up
-      this.indentLevelCounts[level + 1] = 0;
+      this.indentLevelCounts.remove(level + 1);
     }
     int count = (this.indentLevelCounts[level] ?? 0) + 1;
     this.indentLevelCounts[level] = count;