A simple, unified fingerprint authentication library for Android with RxJava extensions.

Eliminates the need to deal with the different available Fingerprint APIs, including Imprint and Samsung Pass.
Fixes undocumented bugs and idiosyncrasies in the underlying APIs.
Supports more Imprint devices than FingerprintManagerCompat from the support library.
Comes with help messages translated in over 80 locales that work with all APIs.
Provides optional RxJava interfaces.

Usage

See the sample app for a complete example.

In your Application.onCreate, initialize Reprint with Reprint.initialize(this). This will load the Marshmallow module, and the Spass module if you included it.

Then, anywhere in your code, you can call Reprint.authenticate to turn on the fingerprint reader and listen for a fingerprint. You can call Reprint.cancelAuthentication to turn the reader off before it finishes normally.

There are two ways to be notified of authentication results: traditional callback, and a ReactiveX Observable.

RxJava interface

If you include the reactive reprint library, you can be notified of authentication results through an Observable (or Flowable with RxJava 2) by calling RxReprint.authenticate. In this case, the subscriber's onNext will be called after each failure and after success.

RxReprint.authenticate()
    .subscribe(result -> {
        switch (result.status) {
            case SUCCESS:
                showSuccess();
                break;
            case NONFATAL_FAILURE:
                showHelp(result.failureReason, result.errorMessage);
                break;
            case FATAL_FAILURE:
                showError(result.failureReason, result.errorMessage);
                break;
        }
    });

The failureReason is an enum value with general categories of reason that the authentication failed. This is useful for displaying custom help messages in your UI.

The errorMessage is a string that will contain some help text provided by the underlying SDK about the failure. You should show this text to the user, or some other message of your own based on the failureReason. This string will never be null from a failure, and will be localized into the current locale.

For detail on the other parameters, see the Javadocs.

One advantage that this interface has is that when the subscriber unsubscribes, the authentication request is automatically canceled. So you could, for example, use the RxLifecycle library to bind the observable, and the authentication will be canceled when your activity pauses.

Traditional Callbacks

If you want to use Reprint without RxJava, you can pass an AuthenticationListener to authenticate. The onFailure callback will be called repeatedly until the sensor is disabled or a fingerprint is authenticated correctly, at which point onSuccess will be called.

Reprint.authenticate(new AuthenticationListener() {
    public void onSuccess(int moduleTag) {
        showSuccess();
    }

    public void onFailure(AuthenticationFailureReason failureReason, boolean fatal,
                          CharSequence errorMessage, int moduleTag, int errorCode) {
        showError(failureReason, fatal, errorMessage, errorCode);
    }
});

Documentation

The javadocs for the Reprint modules are available online:

Installation

Reprint is distributed with jitpack and split up into several libraries, so you can include only the parts that you use.

First, add Jitpack to your gradle repositories.

repositories {
    maven { url "https://jitpack.io" }
}

Then add the core library and optionally the Samsung Pass interface and the ReactiveX interface. Reprint provides support for both RxJava 1 and 2; you should include the module that matches the version of RxJava that you use in your project.

dependencies {
   compile 'com.github.ajalt.reprint:core:3.1.0@aar' // required: supports marshmallow devices
   compile 'com.github.ajalt.reprint:reprint_spass:3.1.0@aar' // optional: support for pre-marshmallow Samsung devices
   compile 'com.github.ajalt.reprint:rxjava:3.1.0@aar' // optional: the RxJava 1 interface
   compile 'com.github.ajalt.reprint:rxjava2:3.1.0@aar' // optional: the RxJava 2 interface
}

Permissions

Reprint requires the following permissions be declared in your AndroidManifest.xml. As long as you use the aar artifacts, these permissions will be included automatically.

<!-- Marshmallow fingerprint permission-->
<uses-permission android:name="android.permission.USE_FINGERPRINT"/>

<!-- Samsung fingerprint permission, only required if you include the Spass module -->
<uses-permission android:name="com.samsung.android.providers.context.permission.WRITE_USE_APP_FEATURE_SURVEY"/>

License

Copyright 2015-2017 AJ Alt

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.