Sample Xamarin Forms application using DependencyService to access native API's for iOS and Android biometrics.

Add this string key to your info.plist file:

<key>NSFaceIDUsageDescription</key>
<string>MyApp needs access to to Face/Touch ID to login</string>

No special permission setup is necessary. FingerprintManager is available on Android 6.0 and higher. NOTE: Starting with Android 9.0, FingerprintManager is deprecrated. Use BiometricPropmt instead (not implemented in this sample).

You will need to create your own UI in Android for the Fingerprint prompt

• Add the IBioAuth.cs interface file to your shared project
• Implement the interface in each of the platform specific projects (BiometricUtils.cs in this sample project)

• Username and password should be saved securily on the device. See Xamarin.Essentials secure storage, or just write your own crypto (I will update this project with a sample)
• It's good practuve to continue to authenticate agaist the server (if your app needs it)