Added setting for biometric inactivity period

FAQ.md

@@ -1901,7 +1901,8 @@ for a list of privacy friendly email providers with advantages and disadvantages
 
 If your device has a biometric sensor, for example a fingerprint sensor, you can enable/disable biometric authentication in the navigation (hamburger) menu of the setup screen.
 When enabled FairEmail will require biometric authentication after a period of inactivity or after the screen has been turned off while FairEmail was running.
-Activity is navigation within FairEmail, for example opening a conversation thread. The inactivity period length is the same as the screen timeout.
+Activity is navigation within FairEmail, for example opening a conversation thread.
+The inactivity period duration can be configured in the miscellaneous settings.
 When biometric authentication is enabled new message notifications will not show any content and FairEmail won't be visible on the Android recents screen.
 
 Biometric authentication is meant to prevent others from seeing your messages only.

app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java

@@ -31,8 +31,10 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.AdapterView;
 import android.widget.Button;
 import android.widget.CompoundButton;
+import android.widget.Spinner;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -51,6 +53,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private SwitchCompat swSubscriptions;
     private TextView tvSubscriptionPro;
     private SwitchCompat swSubscribedOnly;
+    private Spinner spBiometricsTimeout;
     private SwitchCompat swEnglish;
     private SwitchCompat swWatchdog;
     private SwitchCompat swUpdates;
@@ -66,7 +69,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private Group grpDebug;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "badge", "subscriptions", "subscribed_only", "english", "watchdog", "updates", "crash_reports", "debug"
+            "badge", "subscriptions", "subscribed_only", "biometrics_timeout", "english", "watchdog", "updates", "crash_reports", "debug"
     };
 
     private final static String[] RESET_QUESTIONS = new String[]{
@@ -87,6 +90,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swSubscriptions = view.findViewById(R.id.swSubscriptions);
         tvSubscriptionPro = view.findViewById(R.id.tvSubscriptionPro);
         swSubscribedOnly = view.findViewById(R.id.swSubscribedOnly);
+        spBiometricsTimeout = view.findViewById(R.id.spBiometricsTimeout);
         swEnglish = view.findViewById(R.id.swEnglish);
         swWatchdog = view.findViewById(R.id.swWatchdog);
         swUpdates = view.findViewById(R.id.swUpdates);
@@ -132,6 +136,19 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
+        spBiometricsTimeout.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
+                int[] values = getResources().getIntArray(R.array.biometricsTimeoutValues);
+                prefs.edit().putInt("biometrics_timeout", values[position]).apply();
+            }
+
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+                prefs.edit().remove("biometrics_timeout").apply();
+            }
+        });
+
         swEnglish.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -274,6 +291,14 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swSubscriptions.setEnabled(pro);
         swSubscribedOnly.setChecked(prefs.getBoolean("subscribed_only", false));
 
+        int biometrics_timeout = prefs.getInt("biometrics_timeout", 2);
+        int[] biometricTimeoutValues = getResources().getIntArray(R.array.biometricsTimeoutValues);
+        for (int pos = 0; pos < biometricTimeoutValues.length; pos++)
+            if (biometricTimeoutValues[pos] == biometrics_timeout) {
+                spBiometricsTimeout.setSelection(pos);
+                break;
+            }
+
         swEnglish.setChecked(prefs.getBoolean("english", false));
         swWatchdog.setChecked(prefs.getBoolean("watchdog", true));
         swUpdates.setChecked(prefs.getBoolean("updates", true));

app/src/main/java/eu/faircode/email/Helper.java

@@ -21,7 +21,6 @@ package eu.faircode.email;
 
 import android.app.Dialog;
 import android.content.ActivityNotFoundException;
-import android.content.ContentResolver;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
@@ -37,7 +36,6 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Parcel;
-import android.provider.Settings;
 import android.text.Spannable;
 import android.text.Spanned;
 import android.text.format.DateUtils;
@@ -663,17 +661,14 @@ public class Helper {
     static boolean shouldAuthenticate(Context context) {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         boolean biometrics = prefs.getBoolean("biometrics", false);
+        long biometrics_timeout = prefs.getInt("biometrics_timeout", 2) * 60 * 1000L;
 
         if (biometrics) {
-            ContentResolver resolver = context.getContentResolver();
-            int screen_timeout = Settings.System.getInt(resolver, Settings.System.SCREEN_OFF_TIMEOUT, -1);
-            Log.i("Screen timeout=" + screen_timeout);
-
             long now = new Date().getTime();
             long last_authentication = prefs.getLong("last_authentication", 0);
-            Log.i("Authentication valid until=" + new Date(last_authentication + screen_timeout));
+            Log.i("Authentication valid until=" + new Date(last_authentication + biometrics_timeout));
 
-            if (last_authentication + screen_timeout < now)
+            if (last_authentication + biometrics_timeout < now)
                 return true;
 
             prefs.edit().putLong("last_authentication", now).apply();

app/src/main/res/layout/fragment_options_misc.xml

@@ -85,6 +85,28 @@
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@id/swSubscribedOnly" />
 
+            <TextView
+                android:id="@+id/tvBiometricsTimeout"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:layout_marginEnd="48dp"
+                android:text="@string/title_advanced_biometrics_timeout"
+                android:textAppearance="@style/Base.TextAppearance.AppCompat.Small"
+                android:textColor="?android:attr/textColorPrimary"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/tvSubscribedOnlyHint" />
+
+            <Spinner
+                android:id="@+id/spBiometricsTimeout"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:entries="@array/biometricsTimeoutNames"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/tvBiometricsTimeout" />
+
             <androidx.appcompat.widget.SwitchCompat
                 android:id="@+id/swEnglish"
                 android:layout_width="match_parent"
@@ -92,7 +114,7 @@
                 android:layout_marginTop="12dp"
                 android:text="@string/title_advanced_english"
                 app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/tvSubscribedOnlyHint"
+                app:layout_constraintTop_toBottomOf="@id/spBiometricsTimeout"
                 app:switchPadding="12dp" />
 
             <TextView

app/src/main/res/values/strings.xml

@@ -248,6 +248,7 @@
     <string name="title_advanced_badge">Show launcher icon with number of new messages</string>
     <string name="title_advanced_subscriptions">Manage folder subscriptions</string>
     <string name="title_advanced_sync_subscribed">Synchronize subscribed folders only</string>
+    <string name="title_advanced_biometrics_timeout">Biometric authentication timeout</string>
     <string name="title_advanced_english">Force English language</string>
     <string name="title_advanced_watchdog">Periodically check if FairEmail is still active</string>
     <string name="title_advanced_updates">Check for updates</string>
@@ -851,6 +852,22 @@
         <item>Bcc</item>
     </string-array>
 
+    <integer-array name="biometricsTimeoutValues" translatable="false">
+        <item>1</item>
+        <item>2</item>
+        <item>5</item>
+        <item>10</item>
+        <item>20</item>
+    </integer-array>
+
+    <string-array name="biometricsTimeoutNames">
+        <item>One minute</item>
+        <item>2 minutes</item>
+        <item>5 minutes</item>
+        <item>10 minutes</item>
+        <item>20 minutes</item>
+    </string-array>
+
     <array name="colorPicker">
         <item>@color/red</item>
         <item>@color/pink</item>