BiometricPrompt

public class BiometricPrompt
extends Object

java.lang.Object
   ↳ android.hardware.biometrics.BiometricPrompt

A class that manages a system-provided biometric dialog.

Summary

Nested classes

class BiometricPrompt.AuthenticationCallback

Callback structure provided to BiometricPrompt#authenticate(CancellationSignal, Executor, AuthenticationCallback) or BiometricPrompt#authenticate(CryptoObject, CancellationSignal, Executor, AuthenticationCallback). 

class BiometricPrompt.AuthenticationResult

Container for callback data from BiometricPrompt.authenticate(android.os.CancellationSignal, java.util.concurrent.Executor, android.hardware.biometrics.BiometricPrompt.AuthenticationCallback) and BiometricPrompt.authenticate(android.hardware.biometrics.BiometricPrompt.CryptoObject, android.os.CancellationSignal, java.util.concurrent.Executor, android.hardware.biometrics.BiometricPrompt.AuthenticationCallback). 

class BiometricPrompt.Builder

A builder that collects arguments to be shown on the system-provided biometric dialog. 

class BiometricPrompt.CryptoObject

A wrapper class for the cryptographic operations supported by BiometricPrompt. 

Constants

int AUTHENTICATION_RESULT_TYPE_BIOMETRIC

Authentication type reported by AuthenticationResult when the user authenticated by presenting some form of biometric (e.g. fingerprint or face).

int AUTHENTICATION_RESULT_TYPE_DEVICE_CREDENTIAL

Authentication type reported by AuthenticationResult when the user authenticated by entering their device PIN, pattern, or password.

int BIOMETRIC_ACQUIRED_GOOD

The image acquired was good.

int BIOMETRIC_ACQUIRED_IMAGER_DIRTY

The biometric image was too noisy due to suspected or detected dirt on the sensor.

int BIOMETRIC_ACQUIRED_INSUFFICIENT

The biometric image was too noisy to process due to a detected condition or a possibly dirty sensor (See BIOMETRIC_ACQUIRED_IMAGER_DIRTY).

int BIOMETRIC_ACQUIRED_PARTIAL

Only a partial biometric image was detected.

int BIOMETRIC_ACQUIRED_TOO_FAST

The biometric image was incomplete due to quick motion.

int BIOMETRIC_ACQUIRED_TOO_SLOW

The biometric image was unreadable due to lack of motion.

int BIOMETRIC_ERROR_CANCELED

The operation was canceled because the biometric sensor is unavailable.

int BIOMETRIC_ERROR_HW_NOT_PRESENT

The device does not have a biometric sensor.

int BIOMETRIC_ERROR_HW_UNAVAILABLE

The hardware is unavailable.

int BIOMETRIC_ERROR_LOCKOUT

The operation was canceled because the API is locked out due to too many attempts.

int BIOMETRIC_ERROR_LOCKOUT_PERMANENT

The operation was canceled because BIOMETRIC_ERROR_LOCKOUT occurred too many times.

int BIOMETRIC_ERROR_NO_BIOMETRICS

The user does not have any biometrics enrolled.

int BIOMETRIC_ERROR_NO_DEVICE_CREDENTIAL

The device does not have pin, pattern, or password set up.

int BIOMETRIC_ERROR_NO_SPACE

Error state returned for operations like enrollment; the operation cannot be completed because there's not enough storage remaining to complete the operation.

int BIOMETRIC_ERROR_SECURITY_UPDATE_REQUIRED

A security vulnerability has been discovered and the sensor is unavailable until a security update has addressed this issue.

int BIOMETRIC_ERROR_TIMEOUT

Error state returned when the current request has been running too long.

int BIOMETRIC_ERROR_UNABLE_TO_PROCESS

Error state returned when the sensor was unable to process the current image.

int BIOMETRIC_ERROR_USER_CANCELED

The user canceled the operation.

int BIOMETRIC_ERROR_VENDOR

OEMs should use this constant if there are conditions that do not fit under any of the other publicly defined constants, and must provide appropriate strings for these errors to the BiometricPrompt.AuthenticationCallback#onAuthenticationError(int, CharSequence) callback.

long BIOMETRIC_NO_AUTHENTICATION

Returned from BiometricManager#getLastAuthenticationTime(int) when there has been no successful authentication for the given authenticator since boot.

Public methods

void authenticate(CancellationSignal cancel, Executor executor, BiometricPrompt.AuthenticationCallback callback)

This call warms up the biometric hardware, displays a system-provided dialog, and starts scanning for a biometric.

void authenticate(BiometricPrompt.CryptoObject crypto, CancellationSignal cancel, Executor executor, BiometricPrompt.AuthenticationCallback callback)

This call warms up the biometric hardware, displays a system-provided dialog, and starts scanning for a biometric.

int getAllowedAuthenticators()

Gets the type(s) of authenticators that may be invoked by the prompt to authenticate the user, as set by Builder#setAllowedAuthenticators(int).

PromptContentView getContentView()

Gets the content view for the prompt, as set by Builder#setContentView(PromptContentView).

CharSequence getDescription()

Gets the description for the prompt, as set by Builder#setDescription(CharSequence).

Bitmap getLogoBitmap()

Gets the logo bitmap for the prompt, as set by Builder#setLogoBitmap(Bitmap).

String getLogoDescription()

Gets the logo description for the prompt, as set by Builder#setLogoDescription(String).

int getLogoRes()

Gets the drawable resource of the logo for the prompt, as set by Builder#setLogoRes(int).

CharSequence getNegativeButtonText()

Gets the negative button text for the prompt, as set by Builder#setNegativeButton(CharSequence, Executor, DialogInterface.OnClickListener).

CharSequence getSubtitle()

Gets the subtitle for the prompt, as set by Builder#setSubtitle(CharSequence).

CharSequence getTitle()

Gets the title for the prompt, as set by Builder#setTitle(CharSequence).

boolean isConfirmationRequired()

Determines if explicit user confirmation is required by the prompt, as set by Builder#setConfirmationRequired(boolean).

Inherited methods

Constants

AUTHENTICATION_RESULT_TYPE_BIOMETRIC

Added in API level 30 
public static final int AUTHENTICATION_RESULT_TYPE_BIOMETRIC

Authentication type reported by AuthenticationResult when the user authenticated by presenting some form of biometric (e.g. fingerprint or face).

Constant Value: 2 (0x00000002)

AUTHENTICATION_RESULT_TYPE_DEVICE_CREDENTIAL

Added in API level 30 
public static final int AUTHENTICATION_RESULT_TYPE_DEVICE_CREDENTIAL

Authentication type reported by AuthenticationResult when the user authenticated by entering their device PIN, pattern, or password.

Constant Value: 1 (0x00000001)

BIOMETRIC_ACQUIRED_GOOD

public static final int BIOMETRIC_ACQUIRED_GOOD

The image acquired was good.

Constant Value: 0 (0x00000000)

BIOMETRIC_ACQUIRED_IMAGER_DIRTY

public static final int BIOMETRIC_ACQUIRED_IMAGER_DIRTY

The biometric image was too noisy due to suspected or detected dirt on the sensor. For example, it's reasonable return this after multiple BIOMETRIC_ACQUIRED_INSUFFICIENT or actual detection of dirt on the sensor (stuck pixels, swaths, etc.). The user is expected to take action to clean the sensor when this is returned.

Constant Value: 3 (0x00000003)

BIOMETRIC_ACQUIRED_INSUFFICIENT

public static final int BIOMETRIC_ACQUIRED_INSUFFICIENT

The biometric image was too noisy to process due to a detected condition or a possibly dirty sensor (See BIOMETRIC_ACQUIRED_IMAGER_DIRTY).

Constant Value: 2 (0x00000002)

BIOMETRIC_ACQUIRED_PARTIAL

public static final int BIOMETRIC_ACQUIRED_PARTIAL

Only a partial biometric image was detected. During enrollment, the user should be informed on what needs to happen to resolve this problem, e.g. "press firmly on sensor." (for fingerprint)

Constant Value: 1 (0x00000001)

BIOMETRIC_ACQUIRED_TOO_FAST

public static final int BIOMETRIC_ACQUIRED_TOO_FAST

The biometric image was incomplete due to quick motion. For example, this could also happen if the user moved during acquisition. The user should be asked to repeat the operation more slowly.

Constant Value: 5 (0x00000005)

BIOMETRIC_ACQUIRED_TOO_SLOW

public static final int BIOMETRIC_ACQUIRED_TOO_SLOW

The biometric image was unreadable due to lack of motion.

Constant Value: 4 (0x00000004)

BIOMETRIC_ERROR_CANCELED

public static final int BIOMETRIC_ERROR_CANCELED

The operation was canceled because the biometric sensor is unavailable. For example, this may happen when the user is switched, the device is locked or another pending operation prevents or disables it.

Constant Value: 5 (0x00000005)

BIOMETRIC_ERROR_HW_NOT_PRESENT

public static final int BIOMETRIC_ERROR_HW_NOT_PRESENT

The device does not have a biometric sensor.

Constant Value: 12 (0x0000000c)

BIOMETRIC_ERROR_HW_UNAVAILABLE

public static final int BIOMETRIC_ERROR_HW_UNAVAILABLE

The hardware is unavailable. Try again later.

Constant Value: 1 (0x00000001)

BIOMETRIC_ERROR_LOCKOUT

public static final int BIOMETRIC_ERROR_LOCKOUT

The operation was canceled because the API is locked out due to too many attempts. This occurs after 5 failed attempts, and lasts for 30 seconds.

Constant Value: 7 (0x00000007)

BIOMETRIC_ERROR_LOCKOUT_PERMANENT

public static final int BIOMETRIC_ERROR_LOCKOUT_PERMANENT

The operation was canceled because BIOMETRIC_ERROR_LOCKOUT occurred too many times. Biometric authentication is disabled until the user unlocks with strong authentication (PIN/Pattern/Password)

Constant Value: 9 (0x00000009)

BIOMETRIC_ERROR_NO_BIOMETRICS

public static final int BIOMETRIC_ERROR_NO_BIOMETRICS

The user does not have any biometrics enrolled.

Constant Value: 11 (0x0000000b)

BIOMETRIC_ERROR_NO_DEVICE_CREDENTIAL

public static final int BIOMETRIC_ERROR_NO_DEVICE_CREDENTIAL

The device does not have pin, pattern, or password set up. See BiometricPrompt.Builder#setAllowedAuthenticators(int), Authenticators#DEVICE_CREDENTIAL, and BiometricManager#canAuthenticate(int).

Constant Value: 14 (0x0000000e)

BIOMETRIC_ERROR_NO_SPACE

public static final int BIOMETRIC_ERROR_NO_SPACE

Error state returned for operations like enrollment; the operation cannot be completed because there's not enough storage remaining to complete the operation.

Constant Value: 4 (0x00000004)

BIOMETRIC_ERROR_SECURITY_UPDATE_REQUIRED

public static final int BIOMETRIC_ERROR_SECURITY_UPDATE_REQUIRED

A security vulnerability has been discovered and the sensor is unavailable until a security update has addressed this issue. This error can be received if for example, authentication was requested with Authenticators#BIOMETRIC_STRONG, but the sensor's strength can currently only meet Authenticators#BIOMETRIC_WEAK.

Constant Value: 15 (0x0000000f)

BIOMETRIC_ERROR_TIMEOUT

public static final int BIOMETRIC_ERROR_TIMEOUT

Error state returned when the current request has been running too long. This is intended to prevent programs from waiting for the biometric sensor indefinitely. The timeout is platform and sensor-specific, but is generally on the order of 30 seconds.

Constant Value: 3 (0x00000003)

BIOMETRIC_ERROR_UNABLE_TO_PROCESS

public static final int BIOMETRIC_ERROR_UNABLE_TO_PROCESS

Error state returned when the sensor was unable to process the current image.

Constant Value: 2 (0x00000002)

BIOMETRIC_ERROR_USER_CANCELED

public static final int BIOMETRIC_ERROR_USER_CANCELED

The user canceled the operation. Upon receiving this, applications should use alternate authentication (e.g. a password). The application should also provide the means to return to biometric authentication, such as a "use " button.

Constant Value: 10 (0x0000000a)

BIOMETRIC_ERROR_VENDOR

public static final int BIOMETRIC_ERROR_VENDOR

OEMs should use this constant if there are conditions that do not fit under any of the other publicly defined constants, and must provide appropriate strings for these errors to the BiometricPrompt.AuthenticationCallback#onAuthenticationError(int, CharSequence) callback. OEMs should expect that the error message will be shown to users.

Constant Value: 8 (0x00000008)

BIOMETRIC_NO_AUTHENTICATION

public static final long BIOMETRIC_NO_AUTHENTICATION

Returned from BiometricManager#getLastAuthenticationTime(int) when there has been no successful authentication for the given authenticator since boot.

Constant Value: -1 (0xffffffffffffffff)

Public methods

authenticate

Added in API level 28 
public void authenticate (CancellationSignal cancel, 
                Executor executor, 
                BiometricPrompt.AuthenticationCallback callback)

This call warms up the biometric hardware, displays a system-provided dialog, and starts scanning for a biometric. It terminates when BiometricPrompt.AuthenticationCallback.onAuthenticationError(int, java.lang.CharSequence) is called, when BiometricPrompt.AuthenticationCallback.onAuthenticationSucceeded(android.hardware.biometrics.BiometricPrompt.AuthenticationResult) is called, or when the user dismisses the system-provided dialog. This operation can be canceled by using the provided cancel object. The application will receive authentication errors through AuthenticationCallback, and button events through the corresponding callback set in BiometricPrompt.Builder.setNegativeButton(java.lang.CharSequence, java.util.concurrent.Executor, android.content.DialogInterface.OnClickListener). It is safe to reuse the BiometricPrompt object, and calling authenticate(android.os.CancellationSignal, java.util.concurrent.Executor, android.hardware.biometrics.BiometricPrompt.AuthenticationCallback) while an existing authentication attempt is occurring will stop the previous client and start a new authentication. The interrupted client will receive a cancelled notification through BiometricPrompt.AuthenticationCallback.onAuthenticationError(int, java.lang.CharSequence).

Note: Applications generally should not cancel and start authentication in quick succession. For example, to properly handle authentication across configuration changes, it's recommended to use BiometricPrompt in a fragment with setRetainInstance(true). By doing so, the application will not need to cancel/restart authentication during the configuration change.
Requires Manifest.permission.USE_BIOMETRIC

Parameters
cancel CancellationSignal: An object that can be used to cancel authentication. This value cannot be null.
executor Executor: An executor to handle callback events. This value cannot be null. Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). Otherwise, provide an Executor that dispatches to an appropriate thread.
callback BiometricPrompt.AuthenticationCallback: An object to receive authentication events. This value cannot be null.
Throws
IllegalArgumentException If any of the arguments are null.

authenticate

Added in API level 28 
public void authenticate (BiometricPrompt.CryptoObject crypto, 
                CancellationSignal cancel, 
                Executor executor, 
                BiometricPrompt.AuthenticationCallback callback)

This call warms up the biometric hardware, displays a system-provided dialog, and starts scanning for a biometric. It terminates when BiometricPrompt.AuthenticationCallback.onAuthenticationError(int, java.lang.CharSequence) is called, when BiometricPrompt.AuthenticationCallback.onAuthenticationSucceeded(android.hardware.biometrics.BiometricPrompt.AuthenticationResult), or when the user dismisses the system-provided dialog, at which point the crypto object becomes invalid. This operation can be canceled by using the provided cancel object. The application will receive authentication errors through AuthenticationCallback, and button events through the corresponding callback set in Builder#setNegativeButton(CharSequence, Executor, DialogInterface.OnClickListener). It is safe to reuse the BiometricPrompt object, and calling BiometricPrompt#authenticate(CancellationSignal, Executor, AuthenticationCallback) while an existing authentication attempt is occurring will stop the previous client and start a new authentication. The interrupted client will receive a cancelled notification through AuthenticationCallback#onAuthenticationError(int, CharSequence).

Note: Applications generally should not cancel and start authentication in quick succession. For example, to properly handle authentication across configuration changes, it's recommended to use BiometricPrompt in a fragment with setRetainInstance(true). By doing so, the application will not need to cancel/restart authentication during the configuration change.

Per the Android CDD, only biometric authenticators that meet or exceed the requirements for Strong are permitted to integrate with Keystore to perform related cryptographic operations. Therefore, it is an error to call this method after explicitly calling Builder#setAllowedAuthenticators(int) with any biometric strength other than Authenticators#BIOMETRIC_STRONG.
Requires Manifest.permission.USE_BIOMETRIC

Parameters
crypto BiometricPrompt.CryptoObject: A cryptographic operation to be unlocked after successful authentication. This value cannot be null.
cancel CancellationSignal: An object that can be used to cancel authentication. This value cannot be null.
executor Executor: An executor to handle callback events. This value cannot be null. Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). Otherwise, provide an Executor that dispatches to an appropriate thread.
callback BiometricPrompt.AuthenticationCallback: An object to receive authentication events. This value cannot be null.
Throws
IllegalArgumentException If any argument is null, or if the allowed biometric authenticator strength is explicitly set to Authenticators#BIOMETRIC_WEAK. Prior to Build.VERSION_CODES.R, this exception is also thrown if Builder#setDeviceCredentialAllowed(boolean) was explicitly set to true.

getAllowedAuthenticators

Added in API level 30 
public int getAllowedAuthenticators ()

Gets the type(s) of authenticators that may be invoked by the prompt to authenticate the user, as set by Builder#setAllowedAuthenticators(int).

Returns
int A bit field representing the type(s) of authenticators that may be invoked by the prompt (as defined by Authenticators), or 0 if this field was not set. This value may be null.

getContentView

Added in API level 35 
public PromptContentView getContentView ()

Gets the content view for the prompt, as set by Builder#setContentView(PromptContentView).

Returns
PromptContentView The content view for the prompt, or null if the prompt has no content view.

getDescription

Added in API level 30 
public CharSequence getDescription ()

Gets the description for the prompt, as set by Builder#setDescription(CharSequence).

Returns
CharSequence The description for the prompt, or null if the prompt has no description.

getLogoBitmap

Added in API level 35 
public Bitmap getLogoBitmap ()

Gets the logo bitmap for the prompt, as set by Builder#setLogoBitmap(Bitmap). Currently for system applications use only.
Requires Manifest.permission.SET_BIOMETRIC_DIALOG_ADVANCED

Returns
Bitmap The logo bitmap of the prompt, or null if the prompt has no logo bitmap set.

getLogoDescription

Added in API level 35 
public String getLogoDescription ()

Gets the logo description for the prompt, as set by Builder#setLogoDescription(String). Currently for system applications use only.
Requires Manifest.permission.SET_BIOMETRIC_DIALOG_ADVANCED

Returns
String The logo description of the prompt, or null if the prompt has no logo description set.

getLogoRes

Added in API level 35 
public int getLogoRes ()

Gets the drawable resource of the logo for the prompt, as set by Builder#setLogoRes(int). Currently for system applications use only.
Requires Manifest.permission.SET_BIOMETRIC_DIALOG_ADVANCED

Returns
int The drawable resource of the logo, or 0 if the prompt has no logo resource set.

getNegativeButtonText

Added in API level 30 
public CharSequence getNegativeButtonText ()

Gets the negative button text for the prompt, as set by Builder#setNegativeButton(CharSequence, Executor, DialogInterface.OnClickListener).

Returns
CharSequence The negative button text for the prompt, or null if no negative button text was set.

getSubtitle

Added in API level 30 
public CharSequence getSubtitle ()

Gets the subtitle for the prompt, as set by Builder#setSubtitle(CharSequence).

Returns
CharSequence The subtitle for the prompt, or null if the prompt has no subtitle.

getTitle

Added in API level 30 
public CharSequence getTitle ()

Gets the title for the prompt, as set by Builder#setTitle(CharSequence).

Returns
CharSequence The title of the prompt, which is guaranteed to be non-null.

isConfirmationRequired

Added in API level 30 
public boolean isConfirmationRequired ()

Determines if explicit user confirmation is required by the prompt, as set by Builder#setConfirmationRequired(boolean).

Returns
boolean true if explicit user confirmation is required, or false otherwise.