Solved many issues to support this package

CHANGELOG.md

@@ -5,3 +5,7 @@
 ## 1.1.0
 
 - Fixed a bug: URL didn't open within the app, but in browser. Solved already
+
+## 2.0.0
+
+- Null-safety

example/main.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:link/link.dart';
+
+void main() => runApp(MyApp());
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Persistent Bottom Navigation Bar example project',
+      theme: ThemeData(
+        primarySwatch: Colors.blue,
+      ),
+      home: LinkExample(),
+    );
+  }
+}
+
+class LinkExample extends StatelessWidget {
+  const LinkExample({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: SafeArea(
+        child: Center(
+          child: Container(
+            child: Link(
+              child: Text(
+                'Press here to navigate the flutter main page on the web',
+                style: TextStyle(
+                  color: Colors.black,
+                  fontSize: 50,
+                  fontWeight: FontWeight.bold,
+                ),
+              ),
+              url: 'https://flutter.dev/',
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/link.dart

@@ -1,6 +1,6 @@
 /// This library holds just one Material widget
 /// It will wrap a child with an InkWell and launch (if possible) the provided URL
-/// In case it's not possible to launch the URL, it will call the provided onError function if provided 
+/// In case it's not possible to launch the URL, it will call the provided onError function if provided
 library link;
 
 export 'src/link_base.dart' show Link;

lib/src/link_base.dart

@@ -3,21 +3,24 @@ import 'package:url_launcher/url_launcher.dart' as Launcher;
 
 /// Wraps a linkable element around child, opening the provided URL as a String
 class Link extends StatelessWidget {
-
   final Widget child;
   final String url;
-  final VoidCallback onError;
+  final VoidCallback? onError;
 
   /// In case the URL is not openable (i.e., scheme is not supported in your device), it won't launch the URL and call the onError callback if provided.
   /// Otherwise, the URL will be launched within the app
-  const Link({Key key, @required this.url, @required this.child, this.onError: null}) : super(key: key);
+  const Link({Key? key, required this.url, required this.child, this.onError})
+      : super(key: key);
 
   void _launch(String url) async {
     if (await Launcher.canLaunch(url)) {
-      await Launcher.launch(url, forceWebView: true,);
+      await Launcher.launch(
+        url,
+        forceWebView: true,
+      );
     } else {
       if (onError != null) {
-        onError();
+        onError!();
       }
     }
   }