Upgrader

A Flutter package for prompting users to upgrade when there is a newer version of the app in the store.

Overview

When a newer app version is available in the app store, a simple alert prompt or card is displayed.

With today's modern app stores, there is little need to persuade users to upgrade their apps because most are already using the auto upgrade feature. However, there may be times when an app needs to be updated more quickly than usual, and nagging a user to upgrade will entice the upgrade sooner. Also, with Flutter supporting more than just Android and iOS platforms, it will become more likely that users on other app stores need to be nagged about upgrading.

Platform Support

Platform	Automatically Supported?	Appcast Supported?
ANDROID	✅ Yes	✅ Yes
IOS	✅ Yes	✅ Yes
LINUX	❌ No	✅ Yes
MACOS	❌ No	✅ Yes
WEB	❌ No	✅ Yes
WINDOWS	❌ No	✅ Yes

Widgets

The widgets come in two flavors: alert or card. The UpgradeAlert widget is used to display the popup alert prompt, and the UpgradeCard widget is used to display the inline material design card.

There are three buttons displayed to the user: IGNORE, LATER, and UPDATE NOW.

Tapping IGNORE prevents the alert from being displayed again for that version.

Tapping the LATER button just closes the alert allowing the alert to be displayed sometime in the future.

Tapping the UPDATE NOW button takes the user to the App Store (iOS) or Google Play Store (Android) where the user is expected to initiate the update process.

Alert Example

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.

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Upgrader Example',
      home: UpgradeAlert(
          child: Scaffold(
        appBar: AppBar(title: Text('Upgrader Example')),
        body: Center(child: Text('Checking...')),
      )),
    );
  }
}

Screenshot of alert

Cupertino alert example

You can also display a Cupertino style dialog by using the dialogStyle parameter.

  body: UpgradeAlert(
    dialogStyle: UpgradeDialogStyle.cupertino,
    child: Center(child: Text('Checking...')),
  )

Screenshot of Cupertino alert

Card Example

Just return an UpgradeCard widget in your build method and a material design card will be displayed when an update is detected. The widget will have width and height of 0.0 when no update is detected.

return Container(
        margin: EdgeInsets.fromLTRB(12.0, 0.0, 12.0, 0.0),
        child: UpgradeCard());

Screenshot of card

Localization

The text displayed in the upgrader package is localized in many languages, and supports customization.

Release Notes

The release notes are displayed by default when a new version is available. On Android the release notes are taken from the the WHAT'S NEW section on Google Play when available, otherwise the main app description is used. On iOS the release notes are taken from the App Store What's New section. For appcast), the release notes are taken from the description field.

Customization

The alert can be customized by changing the DialogTheme on the MaterialApp, or by overriding methods in the UpgradeAlert class. See these examples for more details:

The card can be customized by changing the CardTheme on the MaterialApp, or by overriding methods in the UpgradeCard class. See these examples for more details:

Here are the custom parameters for UpgradeAlert:

barrierDismissible: used to indicate whether tapping on the barrier will dismiss the dialog, which defaults to false
cupertinoButtonTextStyle: the text style for the cupertino dialog buttons, which defaults to null
dialogStyle: the upgrade dialog style, either material or cupertino, defaults to material, used only by UpgradeAlert, works on Android and iOS.
onIgnore: called when the ignore button is tapped, defaults to null
onLater: called when the later button is tapped, defaults to null
onUpdate: called when the update button is tapped, defaults to null
shouldPopScope: called to determine if the dialog blocks the current route from being popped, which defaults to null
showIgnore: hide or show Ignore button, which defaults to true
showLater: hide or show Later button, which defaults to true
showReleaseNotes: hide or show release notes, which defaults to true

Here are the custom parameters for UpgradeCard:

margin: The empty space that surrounds the card, defaults to null
maxLines: An optional maximum number of lines for the text to span, wrapping if necessary, defaults to null
onIgnore: called when the ignore button is tapped, defaults to null
onLater: called when the later button is tapped, defaults to null
onUpdate: called when the update button is tapped, defaults to null
overflow: How visual overflow should be handled, defaults to null
showIgnore: hide or show Ignore button, which defaults to true
showLater: hide or show Later button, which defaults to true
showReleaseNotes: hide or show release notes, which defaults to true

The Upgrader class can be customized by setting parameters in the constructor, and passing it

client: an HTTP Client that can be replaced for mock testing, defaults to http.Client().
clientHeaders: Provide the HTTP headers used by client, which defaults to null
countryCode: the country code that will override the system locale, which defaults to null
debugDisplayAlways: always force the upgrade to be available, defaults to false
debugDisplayOnce: display the upgrade at least once, defaults to false
debugLogging: display logging statements, which defaults to false
durationUntilAlertAgain: duration until alerting user again, which defaults to 3 days
languageCode: the language code that will override the system locale, which defaults to null
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.
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.

final upgrader = Upgrader(
  storeController: UpgraderStoreController(
    onAndroid: () => UpgraderPlayStore(),
    oniOS: () => UpgraderAppcastStore(appcastURL: appcastURL),
  ),
);

You can even subclass UpgraderStore or an existing store class like UpgraderPlayStore to provide your own customization.

Minimum App Version

The upgrader package can enforce a minimum app version simply by adding a version number to the description field in the app stores.

For the Android Play Store, use this format:

[Minimum supported app version: 1.2.3]

For the iOS App Store, use this format:

[:mav: 1.2.3]

Using that text says that the minimum app version is 1.2.3 and that earlier versions of this app will be forced to update to the current version. The Ignore and Later buttons will automatically be hidden.

After the app containing this text has been submitted for review, approved, and released on the app store, the version number will be visible to the upgrader package. When the minimum app version is updated in the future, all previously installed apps with this package will recognize and honor that value.

This overrides any value supplied in the minAppVersion parameter.

Android

Add this text to the bottom of the full description field in the Google Play Console under the main store listing.

iOS

Add this text to the bottom of the description field in App Store Connect in the description field.

Go Router

When using GoRouter (package go_router) with upgrader, you may need to provide a navigatorKey to the UpgradeAlert widget so that the correct route context is used. Below is part of the code you will need for this. Also, checkout the example/lib/main-gorouter.dart example for a more complete example.

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: 'Upgrader GoRouter Example',
      routerConfig: routerConfig,
      builder: (context, child) {
        return UpgradeAlert(
          navigatorKey: routerConfig.routerDelegate.navigatorKey,
          child: child ?? Text('child'),
        );
      },
    );
  }

Android Back Button

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:

UpgradeAlert(shouldPopScope: () => true);

Country Code

On iOS, when your app is not in the US App Store, which is the default, you must use the countryCode parameter mentioned above. The upgrader package does not know which country app store to use because it is not provided by iOS. It assumes the app is in the US App Store.

On Android, the upgrader package uses the system locale to determine the country code.

Android Language Code

Android description and release notes language default to en.

Limitations

These widgets work on both Android and iOS. When running on Android the Google Play Store will provide the latest app version. When running on iOS the App Store will provide the latest app version. In all cases, the widget will display the prompt at the appropriate times.

On Android, the version number is often not available from the Google Play Store, such as with the Google Maps app. In this case, the version is listed as Varies with device. That is not a valid version for upgrader and cannot be used. The upgrader widget will not be displayed in this case.

There is an appcast that can be used to remotely configure the latest app version. See appcast below for more details.

Appcast

The upgrader package supports Appcast as an UpgraderStore.

An appcast is an RSS feed with one channel that has a collection of items that each describe one app version. The appcast will describe each app version and will provide the latest app version to upgrader that indicates when an upgrade should be recommended.

Appcast is based on the Sparkle framework by Andy Matuschak. You can read the Sparkle documentation here: https://sparkle-project.org/documentation/publishing/.

The appcast must be hosted on a server that can be reached by everyone from the app. The appcast XML file can be autogenerated during the release process, or just manually updated after a release is available on the app store.

The class UpgraderAppcastStore, in this Flutter package, is used by upgrader to download app details from an appcast.

Appcast Example

This is an Appcast example for Android.

static const appcastURL =
    'https://raw.githubusercontent.com/larryaasen/upgrader/master/test/testappcast.xml';
final upgrader = Upgrader(
  storeController: UpgraderStoreController(
    onAndroid: () => UpgraderAppcastStore(appcastURL: appcastURL),
  ),
);

@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...')),
        )),
  );
}

Appcast Sample File

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0" xmlns:sparkle="http://www.andymatuschak.org/xml-namespaces/sparkle">
    <channel>
        <title>Debt Now App - Appcast</title>
        <item>
            <title>Version 1.15.0</title>
            <description>Minor updates and improvements.</description>
            <pubDate>Sun, 30 Dec 2018 12:00:00 +0000</pubDate>
            <enclosure url="https://play.google.com/store/apps/details?id=com.moonwink.treasury" sparkle:version="1.15.0" sparkle:os="android" />
        </item>
    </channel>
</rss>

Appcast Class

final appcast = Appcast();
final items = await appcast.parseAppcastItemsFromUri('https://raw.githubusercontent.com/larryaasen/upgrader/master/test/testappcast.xml');
final bestItem = appcast.bestItem();

Customizing the strings

The strings displayed in upgrader can be customzied by extending the UpgraderMessages class to provide custom values.

As an example, to replace the Ignore button with a custom value, first create a new class that extends UpgraderMessages, and override the buttonTitleIgnore function. Next, when calling UpgradeAlert (or UpgradeCard), add the parameter messages with an instance of your extended class. Here is an example:

class MyUpgraderMessages extends UpgraderMessages {
  @override
  String get buttonTitleIgnore => 'My Ignore';
}

UpgradeAlert(Upgrader(messages: MyUpgraderMessages()));

Language localization

The strings displayed in upgrader are already localized in 35 languages. New languages will be supported in the future with minor updates. It also supports right to left languages.

Languages supported:

English ('en')
Arabic ('ar')
Bengali ('bn')
Chinese ('zh')
Danish ('da')
Dutch ('nl')
Filipino ('fil')
French ('fr')
German ('de')
Greek ('el')
Haitian Creole ('ht')
Hebrew ('he')
Hindi ('hi')
Hungarian ('hu')
Indonesian ('id')
Italian ('it')
Japanese ('ja')
Kazakh ('kk')
Khmer ('km')
Korean ('ko')
Kurdish Sorani ('ku')
Lithuanian ('lt')
Mongolian ('mn')
Norwegian ('nb')
Persian ('fa')
Polish ('pl')
Pashto ('ps')
Portuguese ('pt')
Russian ('ru')
Spanish ('es')
Swedish ('sv')
Tamil ('ta')
Telugu ('te')
Turkish ('tr')
Ukrainian ('uk')
Vietnamese ('vi')

The upgrader package can be supplied with additional languages in your code by extending the UpgraderMessages class to provide custom values.

As an example, to add the Spanish (es) language (which is already provided), first create a new class that extends UpgraderMessages, and override the message function. Next, add a string for each of the messages. Finally, when calling UpgradeAlert (or UpgradeCard), add the parameter messages with an instance of your extended class. Here is an example:

class MySpanishMessages extends UpgraderMessages {
  /// Override the message function to provide custom language localization.
  @override
  String message(UpgraderMessage messageKey) {
    if (languageCode == 'es') {
      switch (messageKey) {
        case UpgraderMessage.body:
          return 'es A new version of {{appName}} is available!';
        case UpgraderMessage.buttonTitleIgnore:
          return 'es Ignore';
        case UpgraderMessage.buttonTitleLater:
          return 'es Later';
        case UpgraderMessage.buttonTitleUpdate:
          return 'es Update Now';
        case UpgraderMessage.prompt:
          return 'es Want to update?';
        case UpgraderMessage.releaseNotes:
          return 'es Release Notes';
        case UpgraderMessage.title:
          return 'es Update App?';
      }
    }
    // Messages that are not provided above can still use the default values.
    return super.message(messageKey);
  }
}

UpgradeAlert(upgrader: Upgrader(messages: MySpanishMessages()));

You can even force the upgrader package to use a specific language, instead of the system language on the device. Just pass the language code to an instance of UpgraderMessages when displaying the alert or card. Here is an example:

UpgradeAlert(upgrader: Upgrader(messages: UpgraderMessages(code: 'es')));

Semantic Versioning

The upgrader package uses the version package that is in compliance with the Semantic Versioning spec at http://semver.org/. It converts any version string to a 3 digit version: MAJOR.MINOR.PATCH. For versions that only use 1 digit (MAJOR), it converts it to a 3 digit version: MAJOR.0.0, and for versions that only use 2 digits (MAJOR.MINOR), it converts it to a 3 digit version: MAJOR.MINOR.0, to be compliant with Semantic Versioning.

Examples

There are plenty of examples that cover various different situations that may help you customize the upgrader experience for your app. Check these out.


main.dart	main_alert_again.dart	main_alert_theme.dart
main_appcast.dart	main_card.dart	main_card_theme.dart
main_cupertino.dart	main_custom_alert.dart	main_custom_card.dart
main_dialog_key.dart	main_driver.dart	main_gorouter.dart
main_localized_rtl.dart	main_macos.dart	main_messages.dart
main_min_app_version.dart	main_multiple.dart	main_stateful.dart
main_subclass.dart

Tapping UPDATE NOW button issue on Android

Seeing an error similar to this on Android after tapping the UPDATE NOW button?

I/UrlLauncher(11833): component name for https://www.google.com/ is null

Adding this to the AndroidManifest.xml file will solve this issue. Add this at the bottom of the file just above the closing </manifest> tag.

    <queries>
      <intent>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.BROWSABLE" />
        <data android:scheme="https" />
      </intent>
    </queries>

This was taken from this Android documentation: https://developer.android.com/training/package-visibility/use-cases#check-browser-available

iTunes Search API

There is a class in this Flutter package used by the upgrader widgets to download app details from the iTunes Search API. The class ITunesSearchAPI can be used standalone to query iTunes for app details.

ITunesSearchAPI Example

final iTunes = ITunesSearchAPI();
final resultsFuture = iTunes.lookupByBundleId('com.google.Maps');
resultsFuture.then((results) {
    print('results: $results');
});

Results

Command Line App - Android

There is a command line app used to display the results from Google Play Store. The code is located in bin/playstore_lookup.dart, and can be run from the command line like this:

$ cd bin
$ dart playstore_lookup.dart id=com.google.android.apps.mapslite

Results:

playstore_lookup releaseNotes: • Support plus.codes URLs• Bug fixes
playstore_lookup version: 152.0.0
...

Command Line App - iOS

There is a command line app used to display the results from iTunes Search. The code is located in bin/itunes_lookup.dart, and can be run from the command line like this:

$ dart itunes_lookup.dart bundleid=com.google.Maps