external_link_account_modal

Description:

external link account modal

External Link Account Modal #
An easy-to-use widget that complies with Apple's External Link Account design requirements for reader apps.

About the library #

Reader apps are apps that provide one or more of the following digital content types — magazines, newspapers, books, audio, music, or video — as the primary functionality of the app. With reader apps, people can sign in to their account created outside the app, letting them view and enjoy previously purchased media content or content subscriptions on their Apple device.
https://developer.apple.com/support/reader-apps/

The library is meant for reader apps that has applied for and been approved the External Link Account Entitlement.
According the the design specifications, a modal sheet must be displayed before leavning the app. This library aims to simplify the process by providing a ready-to-use Flutter widget. For iOS 16.0 or newer, the native API is called instead of showing the Flutter widget.
Installation #
Add external_link_account_modal: ^[latest_version] to your pubspec.yaml file.
Import the library in your class:
import 'package:external_link_account_modal/external_link_account_modal.dart';
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If you use it in an app that also targets Android, add the line: compileSdkVersion 33 to the build.gradle file.
Usage #
Note: This only covers the usage of the actual widget. For more information about setting up your app after receiving the entitlement, go to https://developer.apple.com/support/reader-apps/
Use ExternalLinkAccountText to create a basic link (blue and underlined according to the design specifications). The link opens a modal sheet containg the required information before actually opening the link in an external app.
Example:
ExternalLinkAccountText(
url: 'https://example.com',
developerName: 'Example Developer',
),
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Note that this library only targets iOS, so you should check if this is the current platform before using the widget. For instance:
Platform.isIOS ? ExternalLinkAccountText(
url: 'https://example.com',
developerName: 'Example Developer',
) : Text('Use a different widget on other platforms')
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iOS 16.0, External Link Account API #
Starting with iOS 16.0 Apple released the External Link Account API that handles the modal sheet automatically. The URL is instead fetched from your Info.plist file and the developer name from the App Store Metadata. Before release the Developer Name can therefore say 'None'.
If your app runs on iOS 16 and/or iPadOS 16 or later, it must use the External Link Account API. If it runs on iOS 15 and/or iPadOS 15 or earlier, it must display a modal sheet following the design specifications on the support page. This library aims to handle both cases.
How it works #
The library calls canMakePayments before opening the modal. If it fails, the modal is never opened. If you want to perform an action when that happens (such as showing a warning), you can use the onCanMakePaymentsFailed variable.
The modal changes appearance based on the current theme (light or dark) according to the design requirements and uses the current device locale (unless provided in the optional locale variable) with the default string from Apple. If the locale is not found, English will be used. After the user clicks "Continue", the URL is launched in an external app (the browser) since a webview would not be approved by Apple.
Setting the locale manually is only applicable for iOS <16.0.
Available locale strings:

en
ar
pt_BR
yue
ca
hr
cs
da
nl
en_AU
en_CA
en_GB
fi
fr
fr_CA
de
el
iw
hi_IN
hu
in
it
ja
ko
ms
no
pl
pt
ro
ru
zh_CN
sk
es
es_MX
sv
th
zh
tr
uk
vi