Merge pull request #119 from android/single_tap_sign_in

Biometric(Single tap credential creation & sign-in) implementation in MyVault Provider

Author: niharika2810

CredentialProvider/MyVault/README.md

@@ -14,6 +14,7 @@ The app demonstrates how to:
 - Register as a `CredentialProviderService` so that users can store and retrieve passwords and passkeys using the app.
 - Save passwords/passkeys to the app. These are stored locally in a database for demonstration purposes only. In a real app this data should be sent to a server to allow the user's credentials to be synchronized across all their devices.
 - Retrieve credentials from the app to assist with user login in another app or website.
+- Implement your own biometric prompts for single-tap credential creation and sign-in.
 - Delete passkeys or passwords.
 
 # Requirements
@@ -104,6 +105,9 @@ These additional activities are described below.
 
 For more detailed information on how to create, save and retrieve credentials using the Credential Manager API, refer to the [official documentation]((https://developer.android.com/training/sign-in/credential-provider))
 
+To implement your own biometrics prompt, refer to the [biometrics documentation](https://developer.android.com/identity/sign-in/single-tap-biometric)
+
+
 ## License
 
 The **MyVault Sample** is distributed under the terms of the Apache License (Version 2.0).

CredentialProvider/MyVault/app/build.gradle.kts

@@ -22,12 +22,12 @@ plugins {
 android {
     namespace = "com.example.android.authentication.myvault"
 
-    compileSdkPreview = "VanillaIceCream"
+    compileSdk = 35
 
     defaultConfig {
         applicationId = "com.example.android.authentication.myvault"
         minSdk = 34
-        targetSdkPreview = "VanillaIceCream"
+        targetSdk= 35
         versionCode = 1
         versionName = "1.0"
 

CredentialProvider/MyVault/app/src/main/java/com/example/android/authentication/myvault/AppDependencies.kt

@@ -40,7 +40,7 @@ object AppDependencies {
 
     var providerIcon: Icon? = null
 
-    lateinit var RPIconDataSource: RPIconDataSource
+    lateinit var rpIconDataSource: RPIconDataSource
 
     /**
      * Initializes the core components required for the application's data storage and icon handling.
@@ -63,7 +63,7 @@ object AppDependencies {
             .fallbackToDestructiveMigration()
             .build()
 
-        RPIconDataSource = RPIconDataSource(context.applicationInfo.dataDir)
+        rpIconDataSource = RPIconDataSource(context.applicationInfo.dataDir)
         providerIcon = Icon.createWithResource(context, R.drawable.android_secure)
 
         credentialsRepository =

CredentialProvider/MyVault/app/src/main/java/com/example/android/authentication/myvault/BiometricErrorUtils.kt

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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.
+ */
+package com.example.android.authentication.myvault
+
+import android.annotation.SuppressLint
+import android.content.Context
+import androidx.credentials.provider.BiometricPromptResult
+
+/**
+ * Utility class for handling biometric authentication errors.
+ *
+ * <p>This class provides a collection of static utility methods for managing
+ * and processing errors that may occur during biometric authentication flows.
+ * It encapsulates the logic for extracting error information from
+ * {@link BiometricPromptResult} objects and constructing user-friendly error
+ * messages.
+ *
+ * <p>The primary function of this class is to centralize the error-handling
+ * logic related to biometric authentication, promoting code reuse and
+ * maintainability.
+ */
+object BiometricErrorUtils {
+
+    /**
+     * Checks if there was an error during the biometric authentication flow and returns an error message if so.
+     *
+     * <p>This method determines whether the biometric authentication flow resulted in
+     * an error. It checks if the {@link BiometricPromptResult} is null or if the
+     * authentication was successful. If neither of these conditions is met, it
+     * extracts the error code and message from the {@link BiometricPromptResult},
+     * constructs an error message, and returns it.
+     *
+     * <p>The error message is built using the following format:
+     * "Biometric Error Code: [errorCode] [errorMessage] Other providers may be available."
+     *
+     * @param context               The context used to retrieve string resources.
+     * @param biometricPromptResult The result of the biometric authentication prompt.
+     * @return An error message if there was an error during the biometric flow, or an empty string otherwise.
+     */
+    @SuppressLint("StringFormatMatches")
+    fun getBiometricErrorMessage(
+        context: Context,
+        biometricPromptResult: BiometricPromptResult?,
+    ): String {
+        // If the biometricPromptResult is null, there was no error.
+        if (biometricPromptResult == null) return context.getString(R.string.empty)
+
+        // If the biometricPromptResult indicates success, there was no error.
+        if (biometricPromptResult.isSuccessful) return context.getString(R.string.empty)
+
+        // Initialize default values for the error code and message.
+        var biometricAuthErrorCode = -1
+        var biometricAuthErrorMsg = context.getString(R.string.unknown_failure)
+
+        // Check if there is an authentication error in the biometricPromptResult.
+        if (biometricPromptResult.authenticationError != null) {
+            // Extract the error code and message from the authentication error.
+            biometricAuthErrorCode = biometricPromptResult.authenticationError!!.errorCode
+            biometricAuthErrorMsg = biometricPromptResult.authenticationError!!.errorMsg.toString()
+        }
+
+        // Build the error message to be sent to the client.
+        val errorMessage = buildString {
+            append(
+                context.getString(
+                    R.string.biometric_error_code_with_message,
+                    biometricAuthErrorCode,
+                ),
+            )
+            append(biometricAuthErrorMsg)
+            append(context.getString(R.string.other_providers_error_message))
+        }
+
+        // Indicate that there was an error during the biometric flow.
+        return errorMessage
+    }
+}