Platform setup¶

Android¶

1. Use a FlutterFragmentActivity. The biometric prompt needs a FragmentActivity. Change your MainActivity (android/app/src/main/kotlin/.../MainActivity.kt):

import io.flutter.embedding.android.FlutterFragmentActivity

class MainActivity : FlutterFragmentActivity()

Warning

With the default FlutterActivity, authenticate fails with an error whose code is null_pointer_exception. Any FragmentActivity subclass works, FlutterFragmentActivity is the one Flutter provides.

2. Declare the permission in android/app/src/main/AndroidManifest.xml:

<uses-permission android:name="android.permission.USE_BIOMETRIC" />

Android 9 and older

On Android 9 (API 28) and older the prompt is drawn by androidx.biometric with an AppCompat dialog. If your app runs on those versions, make the parent of LaunchTheme and NormalTheme (android/app/src/main/res/values/styles.xml) a Theme.AppCompat theme, for example Theme.AppCompat.DayNight.NoActionBar.

3. Check your minSdk. The plugin requires API 24 or newer. Apps created with a recent Flutter version already use flutter.minSdkVersion, which is enough.

iOS¶

Add the reason why your app uses Face ID to ios/Runner/Info.plist. Without it the app crashes when Face ID is used.

<key>NSFaceIDUsageDescription</key>
<string>Authenticate to access your account.</string>

The minimum deployment target is iOS 15. In ios/Podfile:

platform :ios, '15.0'

macOS¶

No entitlements or usage descriptions are needed. The minimum deployment target is macOS 12. In macos/Podfile:

platform :osx, '12.0'

Swift Package Manager and CocoaPods¶

On iOS and macOS the plugin supports both Swift Package Manager and CocoaPods. Flutter picks the one your app uses, there is nothing to configure.

Linux¶

The plugin uses fprintd to verify fingerprints. It has to be installed, and the user needs an enrolled fingerprint:

sudo apt install fprintd   # Debian / Ubuntu
fprintd-enroll             # enroll a fingerprint for the current user

Windows¶

Windows Hello is supported on Windows 10 version 1607 or newer. The current Windows user must have Windows Hello configured. The system selects the available Hello verifier, which can be a PIN, face, iris or fingerprint.