Checking for support
You should check if the current device supports authentication by biometrics by calling the
// Biometric authentication is available
You can also check for the individual biometry types, for example, to check if fingerprint authentication is available:
if (LocalAuth.service.canAuthenticateWithBiometryType( BiometryType.FINGERPRINT ))
// Fingerprint authentication is available
This function checks a range of conditions to ensure that you can use biometric authentication on the user's device including:
- user has set a passcode
- user has scanned some fingerprints
- you have set appropriate permissions (manifest additions)
Most devices support fingerprint or face biometric authentication and not both.
Authenticating via fingerprint is as simple as calling the
and registering your event listeners.
authenticateWithBiometryType function requires a
reason which is a message that
will be displayed to the user to explain the reason you are asking for authentication.
LocalAuth.service.addEventListener( LocalAuthEvent.AUTH_SUCCESS, authSuccessHandler );
LocalAuth.service.addEventListener( LocalAuthEvent.AUTH_FAILED, authFailedHandler );
LocalAuth.service.authenticateWithBiometryType( "Unlock access to locked feature" );
Then in your event listeners:
function authSuccessHandler( event:LocalAuthEvent ):void
trace( "localAuth_authSuccessHandler" );
function authFailedHandler( event:LocalAuthEvent ):void
trace( "localAuth_authFailedHandler: " + event.errorCode + "::" +event.message );
AUTH_SUCCESS event will be fired only if the user successfully authenticates using
In all other cases the
AUTH_FAILED event is dispatched and you should respond by processing
the errorCode appropriately. The error codes are defined in the
For example if the user cancels the authentication the
will be returned.
An important code to process is the
LocalAuthError.USER_FALLBACK. This is received when the
user has pressed the Enter Password option in the dialog after failing to scan a fingerprint
once. You should respect this decision and provide the ability for the user to authenticate
using your normal method.
You can also specify the biometry type to be used if you require:
"Unlock access to locked feature",
Specifying the biometry type may return
false when the biometry type is not supported
If you wish to programatically cancel the authentication process
you can call
After calling this you should receive an
AUTH_FAILED event to indicate the failure of the authentication process (if an authentication process was occurring at the time).