Add support for the release method on iOS

Author: SandroMachado

README.md

@@ -28,7 +28,7 @@ It provides a **Default View** that prompts the user to place a finger to the iP
 4.0.0 Prefers the new native Android BiometricPrompt lib on any Android >= v23 (M)
 4.0.0 also DEPRECATES support for the legacy library that provides support for Samsung & MeiZu phones
 
-3.0.2 and below: 
+3.0.2 and below:
 Using an expandable Android Fingerprint API library, which combines [Samsung](http://developer.samsung.com/galaxy/pass#) and [MeiZu](http://open-wiki.flyme.cn/index.php?title=%E6%8C%87%E7%BA%B9%E8%AF%86%E5%88%ABAPI)'s official Fingerprint API.
 
 Samsung and MeiZu's Fingerprint SDK supports most devices which system versions less than Android 6.0.
@@ -95,13 +95,13 @@ API level 28+ (Uses Android native BiometricPrompt) ([Reference](https://develop
 <uses-permission android:name="android.permission.USE_BIOMETRIC" />
 ```
 
-API level 23-28 (Uses Android native FingerprintCompat) [Reference](https://developer.android.com/reference/android/Manifest.permission#USE_FINGERPRINT)) 
+API level 23-28 (Uses Android native FingerprintCompat) [Reference](https://developer.android.com/reference/android/Manifest.permission#USE_FINGERPRINT))
 ```xml
 <uses-permission android:name="android.permission.USE_FINGERPRINT" />
 ```
 
 // DEPRECATED in 4.0.0
-API level <23 (Uses device-specific native fingerprinting, if available - Samsung & MeiZu only) [Reference](https://developer.android.com/reference/android/Manifest.permission#USE_FINGERPRINT)) 
+API level <23 (Uses device-specific native fingerprinting, if available - Samsung & MeiZu only) [Reference](https://developer.android.com/reference/android/Manifest.permission#USE_FINGERPRINT))
 ```xml
 <uses-permission android:name="android.permission.USE_FINGERPRINT" />
 ```
@@ -412,7 +412,7 @@ handleAuthenticationAttemptedLegacy = (error) => {
 };
 ```
 
-### `release()`: (Android)
+### `release()`:
 Stops fingerprint scanner listener, releases cache of internal state in native code, and cancels native prompt if visible.
 
 - Returns a `Void`
@@ -447,6 +447,7 @@ componentWillUnmount() {
 | DeviceLockedPermanent | Authentication was not successful, device must be unlocked via password |
 | DeviceOutOfMemory | Authentication could not proceed because there is not enough free memory on the device |
 | HardwareError | A hardware error occurred |
+| FingerprintScannerAppCancel | Scanner cancelled by the application |
 | FingerprintScannerUnknownError | Could not authenticate for an unknown reason |
 | FingerprintScannerNotSupported | Device does not support Fingerprint Scanner |
 | FingerprintScannerNotEnrolled  | Authentication could not start because Fingerprint Scanner has no enrolled fingers |

ios/ReactNativeFingerprintScanner.m

@@ -8,11 +8,16 @@
 
 @implementation ReactNativeFingerprintScanner
 
+static LAContext *context = nil;
+
 RCT_EXPORT_MODULE();
 
 RCT_EXPORT_METHOD(isSensorAvailable: (RCTResponseSenderBlock)callback)
 {
-    LAContext *context = [[LAContext alloc] init];
+    if (context == nil) {
+        context = [[LAContext alloc] init];
+    }
+
     NSError *error;
 
     if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {
@@ -47,7 +52,15 @@ @implementation ReactNativeFingerprintScanner
                   fallback: (BOOL)fallbackEnabled
                   callback: (RCTResponseSenderBlock)callback)
 {
-    LAContext *context = [[LAContext alloc] init];
+    if (context != nil) {
+        [context invalidate];
+
+        return;
+    }
+
+    context = [[LAContext alloc] init];
+
+
     NSError *error;
 
     // Toggle fallback button
@@ -62,6 +75,8 @@ @implementation ReactNativeFingerprintScanner
                 localizedReason:reason
                           reply:^(BOOL success, NSError *error)
          {
+            context = nil;
+
              // Failed Authentication
              if (error) {
                  NSString *errorReason;
@@ -95,6 +110,10 @@ @implementation ReactNativeFingerprintScanner
                          errorReason = @"FingerprintScannerNotEnrolled";
                          break;
 
+                    case LAErrorAppCancel:
+                        errorReason = @"FingerprintScannerAppCancel";
+                        break;
+
                      default:
                          errorReason = @"FingerprintScannerUnknownError";
                          break;
@@ -121,6 +140,17 @@ @implementation ReactNativeFingerprintScanner
     }
 }
 
+RCT_EXPORT_METHOD(invalidate)
+{
+    if (context == nil) {
+        context = [[LAContext alloc] init];
+    }
+
+    [context invalidate];
+
+    context = nil;
+}
+
 - (NSString *)getBiometryType:(LAContext *)context
 {
     if (@available(iOS 11, *)) {
@@ -130,4 +160,5 @@ - (NSString *)getBiometryType:(LAContext *)context
     return @"Touch ID";
 }
 
+
 @end

src/release.ios.js

@@ -1 +1,9 @@
-export default () => null;
+import { NativeModules } from 'react-native';
+
+const { ReactNativeFingerprintScanner } = NativeModules;
+
+export default () => {
+  return new Promise(() => {
+    ReactNativeFingerprintScanner.invalidate();
+  });
+}