Make sure a fingerprint is enrolled before showing the fingerprint option

app/src/main/java/me/impy/aegis/AuthActivity.java

@@ -1,13 +1,9 @@
 package me.impy.aegis;
 
-import android.Manifest;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
-import android.content.pm.PackageManager;
 import android.hardware.fingerprint.FingerprintManager;
-import android.os.Build;
-import android.support.v4.app.ActivityCompat;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
@@ -30,7 +26,7 @@ import me.impy.aegis.crypto.slots.FingerprintSlot;
 import me.impy.aegis.crypto.slots.PasswordSlot;
 import me.impy.aegis.crypto.slots.Slot;
 import me.impy.aegis.crypto.slots.SlotCollection;
-import me.impy.aegis.finger.FingerprintUiHelper;
+import me.impy.aegis.helpers.FingerprintUiHelper;
 import me.impy.aegis.helpers.AuthHelper;
 
 public class AuthActivity extends AppCompatActivity implements FingerprintUiHelper.Callback, SlotCollectionTask.Callback {
@@ -56,11 +52,8 @@ public class AuthActivity extends AppCompatActivity implements FingerprintUiHelp
         _slots = (SlotCollection) intent.getSerializableExtra("slots");
 
         // only show the fingerprint controls if the api version is new enough, permission is granted, a scanner is found and a fingerprint slot is found
-        Context context = getApplicationContext();
+        FingerprintManager manager = FingerprintUiHelper.getManager(this);
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+        if (manager != null && _slots.has(FingerprintSlot.class)) {
-            FingerprintManager manager = (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);
-            if (ActivityCompat.checkSelfPermission(context, Manifest.permission.USE_FINGERPRINT) == PackageManager.PERMISSION_GRANTED && manager.isHardwareDetected()) {
-                if (_slots.has(FingerprintSlot.class)) {
             try {
                 KeyStoreHandle handle = new KeyStoreHandle();
                 if (handle.keyExists()) {
@@ -73,8 +66,6 @@ public class AuthActivity extends AppCompatActivity implements FingerprintUiHelp
                 throw new UndeclaredThrowableException(e);
             }
         }
-            }
-        }
 
         Button button = findViewById(R.id.button_decrypt);
         button.setOnClickListener(new View.OnClickListener() {

app/src/main/java/me/impy/aegis/CustomAuthenticatedSlide.java

@@ -22,10 +22,9 @@ import java.lang.reflect.UndeclaredThrowableException;
 import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
 
-import me.impy.aegis.crypto.CryptoUtils;
 import me.impy.aegis.crypto.KeyStoreHandle;
 import me.impy.aegis.crypto.slots.Slot;
-import me.impy.aegis.finger.FingerprintUiHelper;
+import me.impy.aegis.helpers.FingerprintUiHelper;
 import me.impy.aegis.helpers.AuthHelper;
 
 public class CustomAuthenticatedSlide extends Fragment implements FingerprintUiHelper.Callback, ISlidePolicy, ISlideSelectionListener {

app/src/main/java/me/impy/aegis/CustomAuthenticationSlide.java

@@ -1,14 +1,10 @@
 package me.impy.aegis;
 
-import android.Manifest;
 import android.content.Context;
 import android.content.Intent;
-import android.content.pm.PackageManager;
 import android.hardware.fingerprint.FingerprintManager;
-import android.os.Build;
 import android.os.Bundle;
 import android.support.design.widget.Snackbar;
-import android.support.v4.app.ActivityCompat;
 import android.support.v4.app.Fragment;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -19,6 +15,8 @@ import android.widget.TextView;
 
 import com.github.paolorotolo.appintro.ISlidePolicy;
 
+import me.impy.aegis.helpers.FingerprintUiHelper;
+
 public class CustomAuthenticationSlide extends Fragment implements ISlidePolicy, RadioGroup.OnCheckedChangeListener {
     public static final int CRYPT_TYPE_INVALID = 0;
     public static final int CRYPT_TYPE_NONE = 1;
@@ -31,22 +29,19 @@ public class CustomAuthenticationSlide extends Fragment implements ISlidePolicy,
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         final View view = inflater.inflate(R.layout.fragment_authentication_slide, container, false);
-        final Context context = getContext();
 
         _buttonGroup = view.findViewById(R.id.rg_authenticationMethod);
         _buttonGroup.setOnCheckedChangeListener(this);
         onCheckedChanged(_buttonGroup, _buttonGroup.getCheckedRadioButtonId());
 
         // only show the fingerprint option if the api version is new enough, permission is granted and a scanner is found
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+        FingerprintManager manager = FingerprintUiHelper.getManager(getContext());
-            FingerprintManager fingerprintManager = (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);
+        if (manager != null) {
-            if (ActivityCompat.checkSelfPermission(context, Manifest.permission.USE_FINGERPRINT) == PackageManager.PERMISSION_GRANTED && fingerprintManager.isHardwareDetected()) {
             RadioButton button = view.findViewById(R.id.rb_fingerprint);
             TextView text = view.findViewById(R.id.text_rb_fingerprint);
             button.setVisibility(View.VISIBLE);
             text.setVisibility(View.VISIBLE);
         }
-        }
 
         view.findViewById(R.id.main).setBackgroundColor(_bgColor);
         return view;

app/src/main/java/me/impy/aegis/helpers/FingerprintUiHelper.java

@@ -17,8 +17,10 @@
  * limitations under the License
  */
 
-package me.impy.aegis.finger;
+package me.impy.aegis.helpers;
 
+import android.Manifest;
+import android.content.Context;
 import android.hardware.fingerprint.FingerprintManager;
 import android.os.Build;
 import android.os.CancellationSignal;
@@ -57,6 +59,18 @@ public class FingerprintUiHelper extends FingerprintManager.AuthenticationCallba
         mCallback = callback;
     }
 
+    public static FingerprintManager getManager(Context context) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            if (PermissionHelper.granted(context, Manifest.permission.USE_FINGERPRINT)) {
+                FingerprintManager manager = (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);
+                if (manager != null && manager.isHardwareDetected() && manager.hasEnrolledFingerprints()) {
+                    return manager;
+                }
+            }
+        }
+        return null;
+    }
+
     public boolean isFingerprintAuthAvailable() {
         // The line below prevents the false positive inspection from Android Studio
         // noinspection ResourceType

app/src/main/java/me/impy/aegis/helpers/PermissionHelper.java

@@ -1,8 +1,10 @@
 package me.impy.aegis.helpers;
 
 import android.app.Activity;
+import android.content.Context;
 import android.content.pm.PackageManager;
 import android.support.v4.app.ActivityCompat;
+import android.support.v4.content.ContextCompat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -12,10 +14,14 @@ public class PermissionHelper {
 
     }
 
+    public static boolean granted(Context context, String permission) {
+        return ContextCompat.checkSelfPermission(context, permission) == PackageManager.PERMISSION_GRANTED;
+    }
+
     public static boolean request(Activity activity, int requestCode, String... perms) {
         List<String> deniedPerms = new ArrayList<>();
         for (String permission : perms) {
-            if (ActivityCompat.checkSelfPermission(activity, permission) == PackageManager.PERMISSION_DENIED) {
+            if (!granted(activity, permission)) {
                 deniedPerms.add(permission);
             }
         }