Change LocalAuth to use Biometric API

packages/local_auth/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.5.0
+ * **Breaking change**. Update the Android API to use androidx Biometric package. This gives
+   the prompt the updated Material look. However, it also requires the activity to be a
+   FragmentActivity. Users can switch to FlutterFragmentActivity in their main app to migrate.
+
 ## 0.4.0+1
 
 * Log a more detailed warning at build time about the previous AndroidX

packages/local_auth/android/build.gradle

@@ -47,5 +47,7 @@ android {
 }
 
 dependencies {
-    api "androidx.core:core:1.1.0-alpha03"
+    api "androidx.core:core:1.1.0-beta01"
+    api "androidx.biometric:biometric:1.0.0-alpha04"
+    api "androidx.fragment:fragment:1.1.0-alpha06"
 }

packages/local_auth/android/src/main/java/io/flutter/plugins/localauth/AuthenticationHelper.java

@@ -20,11 +20,10 @@
 import android.view.ContextThemeWrapper;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.widget.ImageView;
 import android.widget.TextView;
-import androidx.core.content.ContextCompat;
+import androidx.biometric.BiometricPrompt;
 import androidx.core.hardware.fingerprint.FingerprintManagerCompat;
-import androidx.core.os.CancellationSignal;
+import androidx.fragment.app.FragmentActivity;
 import io.flutter.plugin.common.MethodCall;
 
 /**
@@ -33,20 +32,9 @@
  * <p>One instance per call is generated to ensure readable separation of executable paths across
  * method calls.
  */
-class AuthenticationHelper extends FingerprintManagerCompat.AuthenticationCallback
+class AuthenticationHelper extends BiometricPrompt.AuthenticationCallback
     implements Application.ActivityLifecycleCallbacks {
 
-  /** How long will the fp dialog be delayed to dismiss. */
-  private static final long DISMISS_AFTER_MS = 300;
-
-  private static final String CANCEL_BUTTON = "cancelButton";
-
-  /** Captures the state of the fingerprint dialog. */
-  private enum DialogState {
-    SUCCESS,
-    FAILURE
-  }
-
   /** The callback that handles the result of this authentication process. */
   interface AuthCompletionHandler {
 
@@ -69,30 +57,33 @@ interface AuthCompletionHandler {
     void onError(String code, String error);
   }
 
-  private final Activity activity;
+  private final FragmentActivity activity;
   private final AuthCompletionHandler completionHandler;
   private final KeyguardManager keyguardManager;
   private final FingerprintManagerCompat fingerprintManager;
   private final MethodCall call;
+  private final BiometricPrompt.PromptInfo promptInfo;
+  private final boolean isAuthSticky;
+  private boolean activityPaused = false;
 
-  /**
-   * The prominent UI element during this transaction. It is used to communicate the state of
-   * authentication to the user.
-   */
-  private AlertDialog fingerprintDialog;
-
-  private CancellationSignal cancellationSignal;
-
-  AuthenticationHelper(
-      Activity activity, MethodCall call, AuthCompletionHandler completionHandler) {
+  public AuthenticationHelper(
+      FragmentActivity activity, MethodCall call, AuthCompletionHandler completionHandler) {
     this.activity = activity;
     this.completionHandler = completionHandler;
     this.call = call;
     this.keyguardManager = (KeyguardManager) activity.getSystemService(Context.KEYGUARD_SERVICE);
     this.fingerprintManager = FingerprintManagerCompat.from(activity);
+    this.isAuthSticky = call.argument("stickyAuth");
+    this.promptInfo =
+        new BiometricPrompt.PromptInfo.Builder()
+            .setDescription((String) call.argument("localizedReason"))
+            .setTitle((String) call.argument("signInTitle"))
+            .setSubtitle((String) call.argument("fingerprintHint"))
+            .setNegativeButtonText((String) call.argument("cancelButton"))
+            .build();
   }
 
-  void authenticate() {
+  public void authenticate() {
     if (fingerprintManager.isHardwareDetected()) {
       if (keyguardManager.isKeyguardSecure() && fingerprintManager.hasEnrolledFingerprints()) {
         start();
@@ -112,33 +103,18 @@ void authenticate() {
     }
   }
 
+  /** Start the fingerprint listener. */
   private void start() {
     activity.getApplication().registerActivityLifecycleCallbacks(this);
-    resume();
-  }
-
-  private void resume() {
-    cancellationSignal = new CancellationSignal();
-    showFingerprintDialog();
-    fingerprintManager.authenticate(null, 0, cancellationSignal, this, null);
-  }
-
-  private void pause() {
-    if (cancellationSignal != null) {
-      cancellationSignal.cancel();
-    }
-    if (fingerprintDialog != null && fingerprintDialog.isShowing()) {
-      fingerprintDialog.dismiss();
-    }
+    new BiometricPrompt(activity, activity.getMainExecutor(), this).authenticate(promptInfo);
   }
 
   /**
-   * Stops the fingerprint listener and dismisses the fingerprint dialog.
+   * Stops the fingerprint listener.
    *
    * @param success If the authentication was successful.
    */
   private void stop(boolean success) {
-    pause();
     activity.getApplication().unregisterActivityLifecycleCallbacks(this);
     if (success) {
       completionHandler.onSuccess();
@@ -147,99 +123,55 @@ private void stop(boolean success) {
     }
   }
 
-  /**
-   * If the activity is paused or stopped, we have to stop listening for fingerprint. Otherwise,
-   * user can still interact with fp reader in the background.. Sigh..
-   */
-  @Override
-  public void onActivityPaused(Activity activity) {
-    if (call.argument("stickyAuth")) {
-      pause();
-    } else {
-      stop(false);
-    }
-  }
-
   @Override
-  public void onActivityResumed(Activity activity) {
-    if (call.argument("stickyAuth")) {
-      resume();
+  public void onAuthenticationError(int errorCode, CharSequence errString) {
+    if (activityPaused && isAuthSticky) {
+      return;
     }
-  }
 
-  @Override
-  public void onAuthenticationError(int errMsgId, CharSequence errString) {
-    updateFingerprintDialog(DialogState.FAILURE, errString.toString());
+    // Either the authentication got cancelled by user or we are not interested
+    // in sticky auth, so return failure.
+    stop(false);
   }
 
   @Override
-  public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
-    updateFingerprintDialog(DialogState.FAILURE, helpString.toString());
+  public void onAuthenticationSucceeded(BiometricPrompt.AuthenticationResult result) {
+    stop(true);
   }
 
   @Override
   public void onAuthenticationFailed() {
-    updateFingerprintDialog(
-        DialogState.FAILURE, (String) call.argument("fingerprintNotRecognized"));
+    stop(false);
   }
 
+  /**
+   * If the activity is paused, we keep track because fingerprint dialog simply returns "User
+   * cancelled" when the activity is paused.
+   */
   @Override
-  public void onAuthenticationSucceeded(FingerprintManagerCompat.AuthenticationResult result) {
-    updateFingerprintDialog(DialogState.SUCCESS, (String) call.argument("fingerprintSuccess"));
-    new Handler(Looper.myLooper())
-        .postDelayed(
-            new Runnable() {
-              @Override
-              public void run() {
-                stop(true);
-              }
-            },
-            DISMISS_AFTER_MS);
-  }
-
-  private void updateFingerprintDialog(DialogState state, String message) {
-    if (cancellationSignal.isCanceled() || !fingerprintDialog.isShowing()) {
-      return;
-    }
-    TextView resultInfo = (TextView) fingerprintDialog.findViewById(R.id.fingerprint_status);
-    ImageView icon = (ImageView) fingerprintDialog.findViewById(R.id.fingerprint_icon);
-    switch (state) {
-      case FAILURE:
-        icon.setImageResource(R.drawable.fingerprint_warning_icon);
-        resultInfo.setTextColor(ContextCompat.getColor(activity, R.color.warning_color));
-        break;
-      case SUCCESS:
-        icon.setImageResource(R.drawable.fingerprint_success_icon);
-        resultInfo.setTextColor(ContextCompat.getColor(activity, R.color.success_color));
-        break;
+  public void onActivityPaused(Activity ignored) {
+    if (isAuthSticky) {
+      activityPaused = true;
     }
-    resultInfo.setText(message);
   }
 
-  // Suppress inflateParams lint because dialogs do not need to attach to a parent view.
-  @SuppressLint("InflateParams")
-  private void showFingerprintDialog() {
-    View view = LayoutInflater.from(activity).inflate(R.layout.scan_fp, null, false);
-    TextView fpDescription = (TextView) view.findViewById(R.id.fingerprint_description);
-    TextView title = (TextView) view.findViewById(R.id.fingerprint_signin);
-    TextView status = (TextView) view.findViewById(R.id.fingerprint_status);
-    fpDescription.setText((String) call.argument("localizedReason"));
-    title.setText((String) call.argument("signInTitle"));
-    status.setText((String) call.argument("fingerprintHint"));
-    Context context = new ContextThemeWrapper(activity, R.style.AlertDialogCustom);
-    OnClickListener cancelHandler =
-        new OnClickListener() {
-          @Override
-          public void onClick(DialogInterface dialog, int which) {
-            stop(false);
-          }
-        };
-    fingerprintDialog =
-        new AlertDialog.Builder(context)
-            .setView(view)
-            .setNegativeButton((String) call.argument(CANCEL_BUTTON), cancelHandler)
-            .setCancelable(false)
-            .show();
+  @Override
+  public void onActivityResumed(Activity ignored) {
+    if (isAuthSticky) {
+      activityPaused = false;
+      final BiometricPrompt prompt =
+          new BiometricPrompt(activity, activity.getMainExecutor(), this);
+      // When activity is resuming, we cannot show the prompt right away. We need to post it to the UI queue.
+      new Handler(Looper.myLooper())
+          .postDelayed(
+              new Runnable() {
+                @Override
+                public void run() {
+                  prompt.authenticate(promptInfo);
+                }
+              },
+              100);
+    }
   }
 
   // Suppress inflateParams lint because dialogs do not need to attach to a parent view.
@@ -269,7 +201,7 @@ public void onClick(DialogInterface dialog, int which) {
     new AlertDialog.Builder(context)
         .setView(view)
         .setPositiveButton((String) call.argument("goToSetting"), goToSettingHandler)
-        .setNegativeButton((String) call.argument(CANCEL_BUTTON), cancelHandler)
+        .setNegativeButton((String) call.argument("cancelButton"), cancelHandler)
         .setCancelable(false)
         .show();
   }

packages/local_auth/android/src/main/java/io/flutter/plugins/localauth/LocalAuthPlugin.java

@@ -6,6 +6,7 @@
 
 import android.app.Activity;
 import androidx.core.hardware.fingerprint.FingerprintManagerCompat;
+import androidx.fragment.app.FragmentActivity;
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
@@ -42,14 +43,23 @@ public void onMethodCall(MethodCall call, final Result result) {
         result.error("auth_in_progress", "Authentication in progress", null);
         return;
       }
+
       Activity activity = registrar.activity();
       if (activity == null || activity.isFinishing()) {
         result.error("no_activity", "local_auth plugin requires a foreground activity", null);
         return;
       }
+
+      if (!(activity instanceof FragmentActivity)) {
+        result.error(
+            "no_fragment_activity",
+            "local_auth plugin requires activity to be a FragmentActivity.",
+            null);
+        return;
+      }
       AuthenticationHelper authenticationHelper =
           new AuthenticationHelper(
-              activity,
+              (FragmentActivity) activity,
               call,
               new AuthCompletionHandler() {
                 @Override

packages/local_auth/example/android/app/src/main/java/io/flutter/plugins/localauthexample/MainActivity.java

@@ -5,10 +5,10 @@
 package io.flutter.plugins.localauthexample;
 
 import android.os.Bundle;
-import io.flutter.app.FlutterActivity;
+import io.flutter.app.FlutterFragmentActivity;
 import io.flutter.plugins.GeneratedPluginRegistrant;
 
-public class MainActivity extends FlutterActivity {
+public class MainActivity extends FlutterFragmentActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);

packages/local_auth/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Android and iOS device authentication sensors
   such as Fingerprint Reader and Touch ID.
 author: Flutter Team <[email protected]>
 homepage: https://github.com/flutter/plugins/tree/master/packages/local_auth
-version: 0.4.0+1
+version: 0.5.0
 
 flutter:
   plugin: