Builder

Builder

Builder(context: Context!)

Creates a builder for a BiometricPrompt dialog.

build

open fun build(): BiometricPrompt

Creates a BiometricPrompt.

setAllowedAuthenticators

open fun setAllowedAuthenticators(authenticators: Int): BiometricPrompt.Builder

Optional: Specifies the type(s) of authenticators that may be invoked by BiometricPrompt to authenticate the user. Available authenticator types are defined in Authenticators and can be combined via bitwise OR. Defaults to:

• Authenticators.BIOMETRIC_WEAK for non-crypto authentication, or
• Authenticators.BIOMETRIC_STRONG for crypto-based authentication.

If this method is used and no authenticator of any of the specified types is available at the time BiometricPrompt#authenticate(...) is called, authentication will be canceled and AuthenticationCallback.onAuthenticationError(int, CharSequence) will be invoked with an appropriate error code.

This method should be preferred over setDeviceCredentialAllowed(boolean) and overrides the latter if both are used. Using this method to enable device credential authentication (with Authenticators.DEVICE_CREDENTIAL) will replace the negative button on the prompt, making it an error to also call setNegativeButton(java.lang.CharSequence,java.util.concurrent.Executor,android.content.DialogInterface.OnClickListener).

If unlocking cryptographic operation(s), it is the application's responsibility to request authentication with the proper set of authenticators (e.g. match the authenticators specified during key generation).

setConfirmationRequired

open fun setConfirmationRequired(requireConfirmation: Boolean): BiometricPrompt.Builder

Optional: Sets a hint to the system for whether to require user confirmation after authentication. For example, implicit modalities like face and iris are passive, meaning they don't require an explicit user action to complete authentication. If set to true, these modalities should require the user to take some action (e.g. press a button) before AuthenticationCallback.onAuthenticationSucceeded(AuthenticationResult) is called. Defaults to true.

A typical use case for not requiring confirmation would be for low-risk transactions, such as re-authenticating a recently authenticated application. A typical use case for requiring confirmation would be for authorizing a purchase.

Note that this just passes a hint to the system, which the system may then ignore. For example, a value of false may be ignored if the user has disabled implicit authentication in Settings, or if it does not apply to a particular modality (e.g. fingerprint).

setContentView

open fun setContentView(view: PromptContentView): BiometricPrompt.Builder

Optional: Sets application customized content view that will be shown on the prompt.

Note that the description set by Builder.setDescription(CharSequence) will be overridden by Builder.setContentView(PromptContentView). The view provided to Builder.setContentView(PromptContentView) will be used if both methods are called.

setDescription

open fun setDescription(description: CharSequence): BiometricPrompt.Builder

Optional: Sets a description that will be shown on the prompt.

Note that the description set by Builder.setDescription(CharSequence) will be overridden by Builder.setContentView(PromptContentView). The view provided to Builder.setContentView(PromptContentView) will be used if both methods are called.

setDeviceCredentialAllowed

open fun setDeviceCredentialAllowed(allowed: Boolean): BiometricPrompt.Builder

Deprecated: Replaced by setAllowedAuthenticators(int).

Optional: If enabled, the user will be given the option to authenticate with their device PIN, pattern, or password. Developers should first check android.hardware.biometrics.BiometricManager#canAuthenticate(int) for Authenticators.DEVICE_CREDENTIAL before enabling. If the device is not secured with a credential, AuthenticationCallback.onAuthenticationError(int, CharSequence) will be invoked with BiometricPrompt.BIOMETRIC_ERROR_NO_DEVICE_CREDENTIAL. Defaults to false.

Note that enabling this option replaces the negative button on the prompt with one that allows the user to authenticate with their device credential, making it an error to call setNegativeButton(java.lang.CharSequence,java.util.concurrent.Executor,android.content.DialogInterface.OnClickListener).

setLogoBitmap

open fun setLogoBitmap(logoBitmap: Bitmap): BiometricPrompt.Builder

Optional: Sets the bitmap drawable of the logo that will be shown on the prompt.

Note that using this method is not recommended in most scenarios because the calling application's icon will be used by default. Setting the logo is intended for large bundled applications that perform a wide range of functions and need to show distinct icons for each function.
Requires android.Manifest.permission#SET_BIOMETRIC_DIALOG_ADVANCED

setLogoDescription

open fun setLogoDescription(logoDescription: String): BiometricPrompt.Builder

Optional: Sets logo description text that will be shown on the prompt.

Note that using this method is not recommended in most scenarios because the calling application's name will be used by default. Setting the logo description is intended for large bundled applications that perform a wide range of functions and need to show distinct description for each function.
Requires android.Manifest.permission#SET_BIOMETRIC_DIALOG_ADVANCED

setLogoRes

open fun setLogoRes(logoRes: Int): BiometricPrompt.Builder

Optional: Sets the drawable resource of the logo that will be shown on the prompt.

Note that using this method is not recommended in most scenarios because the calling application's icon will be used by default. Setting the logo is intended for large bundled applications that perform a wide range of functions and need to show distinct icons for each function.
Requires android.Manifest.permission#SET_BIOMETRIC_DIALOG_ADVANCED

setNegativeButton

open fun setNegativeButton(
    text: CharSequence, 
    executor: Executor, 
    listener: DialogInterface.OnClickListener
): BiometricPrompt.Builder

Required: Sets the text, executor, and click listener for the negative button on the prompt. This is typically a cancel button, but may be also used to show an alternative method for authentication, such as a screen that asks for a backup password.

Note that this setting is not required, and in fact is explicitly disallowed, if device credential authentication is enabled via setAllowedAuthenticators(int) or setDeviceCredentialAllowed(boolean).

setSubtitle

open fun setSubtitle(subtitle: CharSequence): BiometricPrompt.Builder

Optional: Sets a subtitle that will be shown on the prompt.

setTitle

open fun setTitle(title: CharSequence): BiometricPrompt.Builder

Required: Sets the title that will be shown on the prompt.