Update readme example

packages/url-launcher/CHANGELOG.md

@@ -1,3 +1,7 @@
+## [0.3.1] - 2017-05-01
+
+* Change to README.md
+
 ## [0.3.0] - 2017-04-27
 
 * Add `canLaunch` method.

packages/url-launcher/README.md

@@ -15,15 +15,20 @@ void main() {
   runApp(new Scaffold(
     body: new Center(
       child: new RaisedButton(
-        onPressed: launchURL,
+        onPressed: _launchURL,
         child: new Text('Show Flutter homepage'),
       ),
     ),
   ));
 }
 
-launchURL() {
-  launch('https://flutter.io');
+_launchURL() async {
+  const url = 'https://flutter.io';
+  if (await canLaunch(url)) {
+    await launch(url);
+  } else {
+    throw 'Could not launch $url';
+  }
 }
 
 ```

packages/url-launcher/example/lib/main.dart

@@ -45,7 +45,7 @@ class _MyHomePageState extends State<MyHomePage> {
     if (await canLaunch(url)) {
       await launch(url);
     } else {
-      throw "Could not launch $url";
+      throw 'Could not launch $url';
     }
   }
 
@@ -72,11 +72,11 @@ class _MyHomePageState extends State<MyHomePage> {
               children: [
                 new Padding(
                   padding: new EdgeInsets.all(16.0),
-                  child: new Text("https://flutter.io"),
+                  child: new Text('https://flutter.io'),
                 ),
                 new RaisedButton(
                   onPressed: _launchUrl,
-                  child: new Text("Go"),
+                  child: new Text('Go'),
                 ),
               ],
             ),