Improve README example code - fix examples, remove outdated params, f…

…ix documentation errors

Co-authored-by: larryaasen <325973+larryaasen@users.noreply.github.com>

README.md

@@ -52,6 +52,11 @@ Tapping the UPDATE NOW button takes the user to the App Store (iOS) or Google Pl
 Just wrap your home widget in the `UpgradeAlert` widget, and it will handle the rest. Make sure `UpgradeAlert`
 is below `MaterialApp` in the widget tree.
 ```dart
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  runApp(const MyApp());
+}
+
 class MyApp extends StatelessWidget {
   const MyApp({super.key});
 
@@ -60,10 +65,11 @@ class MyApp extends StatelessWidget {
     return MaterialApp(
       title: 'Upgrader Example',
       home: UpgradeAlert(
-          child: Scaffold(
-        appBar: AppBar(title: Text('Upgrader Example')),
-        body: Center(child: Text('Checking...')),
-      )),
+        child: Scaffold(
+          appBar: AppBar(title: const Text('Upgrader Example')),
+          body: const Center(child: Text('Checking...')),
+        ),
+      ),
     );
   }
 }
@@ -162,28 +168,28 @@ The `Upgrader` class can be customized by setting parameters in the constructor,
 * messages: optional localized messages used for display in `upgrader`
 * minAppVersion: the minimum app version supported by this app. Earlier versions of this app will be forced to update to the current version. It should be a valid version string like this: ```2.0.13```. Overrides any minimum app version from UpgraderStore. Defaults to ```null```.
 * storeController: a controller that provides the store details for each platform, defaults to `UpgraderStoreController()`.
-* upgraderDevice: an abstraction of the device_info details which is used for the OS version, defaults to `UpgraderDevice()`.
 * upgraderOS: information on which OS this code is running on, defaults to `UpgraderOS()`.
 * willDisplayUpgrade: called when ```upgrader``` determines that an upgrade may
 or may not be displayed, defaults to ```null```
 
 The  `UpgraderStoreController` class is a controller that provides the store details
 for each platform.
 * onAndroid: defaults to `UpgraderPlayStore()` that extends `UpgraderStore`.
-* onFuchsia: defaults to `UpgraderAppStore()` that extends `UpgraderStore`.
-* oniOS: defaults to `null`.
+* onFuchsia: defaults to `null`.
+* oniOS: defaults to `UpgraderAppStore()` that extends `UpgraderStore`.
 * onLinux: defaults to `null`.
 * onMacOS: defaults to `null`.
 * onWeb: defaults to `null`.
 * onWindows: defaults to `null`.
 
 To change the `UpgraderStore` for a platform, replace the platform with a
 different store. Here is an example of using an Appcast on iOS.
-```
+```dart
+const appcastURL = 'https://raw.githubusercontent.com/larryaasen/upgrader/main/test/testappcast.xml';
 final upgrader = Upgrader(
   storeController: UpgraderStoreController(
     onAndroid: () => UpgraderPlayStore(),
-    oniOS: () => UpgraderAppcastStore(appcastURL: appcastURL, osVersion: osVersion),
+    oniOS: () => UpgraderAppcastStore(appcastURL: appcastURL, osVersion: Version(0, 0, 0)),
   ),
 );
 ```
@@ -243,7 +249,7 @@ check out the [example/lib/main_gorouter.dart](example/lib/main_gorouter.dart) e
       builder: (context, child) {
         return UpgradeAlert(
           navigatorKey: routerConfig.routerDelegate.navigatorKey,
-          child: child ?? Text('child'),
+          child: child ?? const Text('child'),
         );
       },
     );
@@ -280,7 +286,7 @@ Example:
 When using the ```UpgradeAlert``` widget, the Android back button will not
 dismiss the alert dialog by default. To allow the back button to dismiss the
 dialog, use ```shouldPopScope``` and return true like this:
-```
+```dart
 UpgradeAlert(shouldPopScope: () => true);
 ```
 
@@ -335,25 +341,38 @@ Flutter package, is used by `upgrader` to download app details from an appcast.
 ### Appcast Example
 This is an Appcast example for Android.
 ```dart
-static const appcastURL =
-    'https://raw.githubusercontent.com/larryaasen/upgrader/main/test/testappcast.xml';
-final upgrader = Upgrader(
-  storeController: UpgraderStoreController(
-    onAndroid: () => UpgraderAppcastStore(appcastURL: appcastURL, osVersion: osVersion),
-  ),
-);
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  static const appcastURL =
+      'https://raw.githubusercontent.com/larryaasen/upgrader/main/test/testappcast.xml';
 
-@override
-Widget build(BuildContext context) {
-  return MaterialApp(
-    title: 'Upgrader Example',
-    home: Scaffold(
-        appBar: AppBar(title: Text('Upgrader Appcast Example')),
-        body: UpgradeAlert(
-          upgrader: upgrader,
-          child: Center(child: Text('Checking...')),
-        )),
+  // Pass the actual OS version for accurate Appcast item filtering.
+  // See example/lib/main_appcast.dart for how to retrieve the OS version
+  // using the device_info_plus package.
+  static final upgrader = Upgrader(
+    storeController: UpgraderStoreController(
+      onAndroid: () => UpgraderAppcastStore(appcastURL: appcastURL, osVersion: Version(0, 0, 0)),
+    ),
   );
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Upgrader Example',
+      home: Scaffold(
+          appBar: AppBar(title: const Text('Upgrader Appcast Example')),
+          body: UpgradeAlert(
+            upgrader: upgrader,
+            child: const Center(child: Text('Checking...')),
+          )),
+    );
+  }
 }
 ```