Display Touch ID dialog on Android (if supported)

mobile/android/app/build.gradle

@@ -152,8 +152,9 @@ dependencies {
     implementation project(':react-native-svg')
     implementation project(':react-native-gesture-handler')
     implementation fileTree(dir: "libs", include: ["*.jar"])
-    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
+    implementation "com.android.support:support-annotations:${rootProject.ext.supportLibVersion}"
     implementation "com.facebook.react:react-native:+"  // From node_modules
+    implementation 'androidx.biometric:biometric:1.0.0-alpha03'
     // Add v8-android - prebuilt libv8.so into APK
     implementation 'org.chromium:v8-android:+'
     addUnimodulesDependencies()

mobile/android/app/src/main/AndroidManifest.xml

@@ -11,6 +11,7 @@
     <!-- OPTIONAL PERMISSIONS, REMOVE WHATEVER YOU DO NOT NEED -->
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.USE_FINGERPRINT" />
+    <uses-permission android:name="android.permission.USE_BIOMETRIC" />
     <uses-permission android:name="android.permission.VIBRATE" />
 
     <!-- These require runtime permissions on M -->

mobile/android/app/src/main/java/com/lightningapp/FingerprintDialogModule.java

@@ -0,0 +1,30 @@
+package com.lightningapp;
+
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.ReactContextBaseJavaModule;
+import com.facebook.react.bridge.ReactMethod;
+import java.util.concurrent.Executors;
+import androidx.biometric.BiometricPrompt;
+
+public class FingerprintDialogModule extends ReactContextBaseJavaModule {
+    public FingerprintDialogModule(ReactApplicationContext reactContext) {
+        super(reactContext); //required by React Native
+    }
+
+    @Override
+    //getName is required to define the name of the module represented in JavaScript
+    public String getName() {
+        return "FingerprintDialog";
+    }
+
+    @ReactMethod
+    public void getBiometricPrompt() {
+        val executor = Executors.newSingleThreadExecutor();
+        BiometricPrompt.Builder()
+          .setTitle("Use your fingerprint to unlock")
+          .setSubtitle("Lightning App requires authentication to continue")
+          .setDescription("Use your fingerprint to unlock the app or press cancel and enter in your pin")
+          .setNegativeButton("Cancel")
+          .build();
+    }
+}

mobile/android/app/src/main/java/com/lightningapp/FingerprintDialogPackage.java

@@ -0,0 +1,28 @@
+package com.lightningapp;
+
+import com.facebook.react.ReactPackage;
+import com.facebook.react.bridge.NativeModule;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.uimanager.ViewManager;
+import com.lightningapp.FingerprintDialogModule;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class FingerprintDialogPackage implements ReactPackage {
+
+    @Override
+    public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public List<NativeModule> createNativeModules(
+            ReactApplicationContext reactContext) {
+        List<NativeModule> modules = new ArrayList<>();
+        //this is where you register the module
+        modules.add(new FingerprintDialogModule(reactContext));
+        return modules;
+    }
+}

mobile/android/app/src/main/java/com/lightningapp/MainApplication.java

@@ -53,7 +53,8 @@ protected List<ReactPackage> getPackages() {
           new SvgPackage(),
           new RNGestureHandlerPackage(),
           new ModuleRegistryAdapter(mModuleRegistryProvider),
-          new LndNativePackage()
+          new LndNativePackage(),
+          new FingerprintDialogPackage()
       );
     }
 

mobile/android/gradle.properties

@@ -16,3 +16,5 @@
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
+android.useAndroidX=true
+android.enableJetifier=true

mobile/package.json

@@ -5,6 +5,7 @@
     "start": "react-native start"
   },
   "dependencies": {
+    "expo-constants": "^7.0.0",
     "expo-font": "^6.0.1",
     "expo-keep-awake": "^6.0.0",
     "expo-local-authentication": "^6.0.0",
@@ -28,7 +29,7 @@
     "react-native-picker-select": "^6.3.2",
     "react-native-share": "^1.2.1",
     "react-native-svg": "^9.6.2",
-    "react-native-unimodules": "^0.5.4",
+    "react-native-unimodules": "^0.7.0-rc.1",
     "react-native-v8": "^0.59.10-patch.1",
     "react-navigation": "^3.11.1"
   },

src/action/auth-mobile.js

@@ -192,15 +192,20 @@ class AuthAction {
   // TouchID & KeyStore Authentication
   //
 
+  async checkFingerprintHardwareAndEnrollment() {
+    const hasHardware = await this._Fingerprint.hasHardwareAsync();
+    const isEnrolled = await this._Fingerprint.isEnrolledAsync();
+    return hasHardware && isEnrolled ? true : false;
+  }
+
   /**
    * Try authenticating the user using either via TouchID/FaceID on iOS
    * or a fingerprint reader on Android.
    * @return {Promise<undefined>}
    */
   async tryFingerprint() {
-    const hasHardware = await this._Fingerprint.hasHardwareAsync();
-    const isEnrolled = await this._Fingerprint.isEnrolledAsync();
-    if (!hasHardware || !isEnrolled) {
+    const hasFingerprint = await this.checkFingerprintHardwareAndEnrollment();
+    if (!hasFingerprint) {
       return;
     }
     const msg = 'Unlock your Wallet';

src/view/pin-mobile.js

@@ -1,5 +1,5 @@
 import React from 'react';
-import { View, StyleSheet } from 'react-native';
+import { NativeModules, View, StyleSheet } from 'react-native';
 import { observer } from 'mobx-react';
 import PropTypes from 'prop-types';
 import Background from '../component/background';
@@ -37,6 +37,12 @@ class PinView extends React.Component {
 
   render() {
     const { store, auth } = this.props;
+    const FingerprintDialog = NativeModules.FingerprintDialog;
+    const hasActiveFingerprint = this.props.auth.checkFingerprintHardwareAndEnrollment();
+
+    if (hasActiveFingerprint) {
+      FingerprintDialog.getBiometricPrompt();
+    }
     return (
       <Background image="purple-gradient-bg">
         <MainContent style={styles.content}>