B4A Library BiometricManager - Biometric Authentication

Erel · Nov 10, 2019

This class replaces FingerprintManager (https://www.b4x.com/android/forum/threads/fingerprint-authentication.72500/#content).
It works with all the device supported biometric authentication features.

Setup:
1. Open B4A Sdk Manager, search for biometric and install androidx.biometric:biometric.
2. Add to the activity:

B4X:

#AdditionalJar: androidx.biometric:biometric
#Extends: android.support.v7.app.AppCompatActivity
'discard the incorrect warning about AppCompat not being used.
#IgnoreWarnings: 32

3. Add to the manifest editor:

B4X:

AddPermission(android.permission.USE_BIOMETRIC)
AddPermission(android.permission.USE_FINGERPRINT)
SetApplicationAttribute(android:theme, "@style/MyAppTheme")
CreateResource(values, theme.xml,
<resources>
    <style name="MyAppTheme" parent="Theme.AppCompat.Light">
    </style>
</resources>
)

Usage:
- Call CanAuthenticate. It will return "SUCCESS" if biometric authentication is supported and configured.
- Call Show to show the authentication dialog and wait for the Complete event.

See the attached example.

hung · Sep 18, 2020

When compiling the sample program.

Erel · Sep 20, 2020

Make sure that android.jar (tools - configure paths) points to the correct SDK.

mohammad javad · Sep 26, 2020

Erel said:
1. Open B4A Sdk Manager, search for biometric and install androidx.biometric:biometric.

Hey
When I open B4A Sdk Manager and search for biometric I can not find androidx.biometric:biometric
Actually before it the Sdk Manager logger shows this:

B4X:

B4A Sdk Manager: 3.7
TempFolder = C:\Users\jafari\AppData\Roaming\ANYWHE~1\BASIC4~1\temp
DataFolder: C:\Users\jafari\AppData\Roaming\B4ASdkManager
SDK version: 4333796
Downloading: https://dl.google.com/dl/android/maven2/master-index.xml
error:
<!DOCTYPE html>
<html lang=en>
  <meta charset=utf-8>
  <meta name=viewport content="initial-scale=1, minimum-scale=1, width=device-width">
  <title>Error 404 (Not Found)!!1</title>
  <style>
    *{margin:0;padding:0}html,code{font:15px/22px arial,sans-serif}html{background:#fff;color:#222;padding:15px}body{margin:7% auto 0;max-width:390px;min-height:180px;padding:30px 0 15px}* > body{background:url(//www.google.com/images/errors/robot.png) 100% 5px no-repeat;padding-right:205px}p{margin:11px 0 22px;overflow:hidden}ins{color:#777;text-decoration:none}a img{border:0}@media screen and (max-width:772px){body{background:none;margin-top:0;max-width:none;padding-right:0}}#logo{background:url(//www.google.com/images/logos/errorpage/error_logo-150x54.png) no-repeat;margin-left:-5px}@media only screen and (min-resolution:192dpi){#logo{background:url(//www.google.com/images/logos/errorpage/error_logo-150x54-2x.png) no-repeat 0% 0%/100% 100%;-moz-border-image:url(//www.google.com/images/logos/errorpage/error_logo-150x54-2x.png) 0}}@media only screen and (-webkit-min-device-pixel-ratio:2){#logo{background:url(//www.google.com/images/logos/errorpage/error_logo-150x54-2x.png) no-repeat;-webkit-background-size:100% 100%}}#logo{display:inline-block;height:54px;width:150px}
  </style>
  <a href=//www.google.com/><span id=logo aria-label=Google></span></a>
  <p><b>404.</b> <ins>That’s an error.</ins>
  <p>  <ins>That’s all we know.</ins>

what is the problem??

Erel · Sep 27, 2020

Based on the logs you are using an old SDK. Carefully follow the installation instructions: https://www.b4x.com/b4a.html

mohammad javad · Oct 1, 2020

In many applications, they make users choose a password in case which touch id ( finger print or biometric authentication or ...) does not work.
1- Is it possible to add something like a button called "using your password" or set an event for "Cancel" button in authentication?
2- Is it possible to change name of "Cancel" button to something else like "Ok"?

Erel · Oct 1, 2020

You can show whatever you like before calling Show. The system dialog is not configurable.

krlos2004 · Nov 21, 2020

show, top.

Erel · Apr 19, 2021

Updated example project:

B4X:

#AdditionalJar: androidx.arch.core:core-runtime

And manifest editor:

B4X:

AddPermission(android.permission.USE_FINGERPRINT)

Erel · Apr 19, 2021

Another update. Apparently the Activity must be an AppCompat activity to work in Android 8.

The example is based on B4XPages. It is recommended to use B4XPages v1.09+ with AppCompat.

jeronimovilar · Oct 19, 2021

I´m trying the BiometricExample and shows in compile:

Convert byte code - optimized dex. Error
Uncaught translation error: com.android.dx.cf.code.SimException: invalid opcode ba (invokedynamic requires --min-sdk-version >= 26)
Uncaught translation error: com.android.dx.cf.code.SimException: invalid opcode ba (invokedynamic requires --min-sdk-version >= 26)
2 errors; aborting

Why?

josejad · Oct 19, 2021

jeronimovilar said:
Why?

Take a look to the forum search for the same error. Please start a new thread as the error is not related with this example, but your SDK

Search Results

www.b4x.com

adriano.freitas · Jun 13, 2022

Hi!
I have just one question: I have an application that at the time was made without the use of B4X Pages. I still haven't been able to convert it. I inserted this function into it and it worked, however, despite the application not using the title bar, when I entered this code the title bar appeared and I could not find how to remove it. Would you help me?

Erel · Nov 22, 2022

Example was updated with targetSdkVersion=31.
Note that AppCompat needs to be referenced.
Depends on B4A v12+.

Jorge Santamaria Magana · Jul 1, 2025

I tried testing the sample project. I have no issues with the configuration — the problem arises when it compiles and runs. When the app launches, it immediately closes, and the console shows no errors, as if everything is working fine. However, I can’t see the start interface; it’s as if the process is being killed. I’m trying to install it directly on the device via USB in developer mode. Is anyone else experiencing the same issue?

Erel · Jul 2, 2025

Check the unfiltered logs. There must be an error message.

Jorge Santamaria Magana · Jul 2, 2025

Trying to read the unfiltered logs, the console generates many messages in one iteration, but you can see something like this:

Erel · Jul 3, 2025

There is nothing here.

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