diff --git a/app/src/main/java/org/shadowice/flocke/andotp/Activities/SecureCaptureActivity.java b/app/src/main/java/org/shadowice/flocke/andotp/Activities/SecureCaptureActivity.java
index 1d6cdd50..880fc0bb 100644
--- a/app/src/main/java/org/shadowice/flocke/andotp/Activities/SecureCaptureActivity.java
+++ b/app/src/main/java/org/shadowice/flocke/andotp/Activities/SecureCaptureActivity.java
@@ -1,11 +1,35 @@
+/*
+ * Copyright (C) 2019-2021 Jakob Nixdorf
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
 package org.shadowice.flocke.andotp.Activities;
 
 import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.os.Build;
+import android.view.Window;
 import android.view.WindowInsets;
 import android.view.WindowInsetsController;
 import android.view.WindowManager;
+
 import com.journeyapps.barcodescanner.CaptureActivity;
 import com.journeyapps.barcodescanner.DecoratedBarcodeView;
 
@@ -14,6 +38,25 @@ import org.shadowice.flocke.andotp.Utilities.Settings;
 import java.util.Locale;
 
 public class SecureCaptureActivity extends CaptureActivity {
+
+    /**
+     * Overwrites {@link CaptureActivity#initializeContent()} to:
+     * <ul>
+     *     <li>preventing the window from appearing in screenshots or from being viewed on
+     *     non-secure displays, if this was enabled in the app settings.</li>
+     *     <li>request hardware acceleration to be turned on.</li>
+     *     <li>hide all screen decorations like navigation and status bars.</li>
+     * </ul>
+     *
+     * <em>
+     *     Note:
+     *     {@link android.app.Activity#setContentView(int)} in {@link CaptureActivity#initializeContent()}
+     *     of super class needs to be called before {@link Window#getInsetsController()}, otherwise NPE will be thrown
+     *     because the top-level view of the current {@link Window}, containing the window decor, is not yet initialized.
+     * </em>
+     *
+     * @return the DecoratedBarcodeView
+     */
     @Override
     @SuppressWarnings("deprecation")
     protected DecoratedBarcodeView initializeContent() {
@@ -22,8 +65,19 @@ public class SecureCaptureActivity extends CaptureActivity {
         setTheme(settings.getTheme());
         setLocale(settings);
 
-        if (!settings.getScreenshotsEnabled())
+        //  This flag must be set before setting the content view of the activity or dialog.
+        getWindow().setFlags(
+                WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
+                WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED
+        );
+
+        // All window flags, that must be set before the window decoration is created, are already set
+        // so we are safe to call super here.
+        DecoratedBarcodeView barcodeScannerView = super.initializeContent();
+
+        if (!settings.getScreenshotsEnabled()) {
             getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
+        }
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
             final WindowInsetsController insetsController = getWindow().getInsetsController();
@@ -32,12 +86,13 @@ public class SecureCaptureActivity extends CaptureActivity {
                 insetsController.setSystemBarsBehavior(WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
             }
         } else {
-            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
+            getWindow().setFlags(
+                    WindowManager.LayoutParams.FLAG_FULLSCREEN,
+                    WindowManager.LayoutParams.FLAG_FULLSCREEN
+            );
         }
 
-        getWindow().setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED, WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);
-
-        return super.initializeContent();
+        return barcodeScannerView;
     }
 
     private void setLocale(Settings settings) {