Update last authentication on user interaction

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

@@ -140,11 +140,26 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
         super.onConfigurationChanged(newConfig);
     }
 
+    @Override
+    public void onUserInteraction() {
+        Log.i("User interaction");
+
+        if (!this.getClass().equals(ActivityMain.class) && Helper.shouldAuthenticate(this)) {
+            finish();
+            startActivity(new Intent(this, ActivityMain.class));
+        }
+    }
+
+    @Override
+    protected void onUserLeaveHint() {
+        Log.i("User leaving");
+    }
+
     @Override
     protected void onStop() {
         super.onStop();
-        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
 
+        PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
         if (pm != null && !pm.isInteractive()) {
             Log.i("Stop with screen off");
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

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

@@ -697,11 +697,11 @@ 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) {
             long now = new Date().getTime();
             long last_authentication = prefs.getLong("last_authentication", 0);
+            long biometrics_timeout = prefs.getInt("biometrics_timeout", 2) * 60 * 1000L;
             Log.i("Authentication valid until=" + new Date(last_authentication + biometrics_timeout));
 
             if (last_authentication + biometrics_timeout < now)