diff --git a/app/src/main/java/org/kontalk/ui/MyKeyActivity.java b/app/src/main/java/org/kontalk/ui/MyKeyActivity.java
index ac668c872..a80269920 100644
--- a/app/src/main/java/org/kontalk/ui/MyKeyActivity.java
+++ b/app/src/main/java/org/kontalk/ui/MyKeyActivity.java
@@ -18,6 +18,7 @@
 
 package org.kontalk.ui;
 
+import android.graphics.Bitmap;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.ImageView;
@@ -36,7 +37,7 @@
  * My key activity.
  * @author Daniele Ricci
  */
-public class MyKeyActivity extends ToolbarActivity {
+public class MyKeyActivity extends ToolbarActivity implements ViewUtils.OnQRCodeGeneratedListener {
     private static final String TAG = Kontalk.TAG;
 
     private View mViewport;
@@ -44,6 +45,7 @@ public class MyKeyActivity extends ToolbarActivity {
     private TextView mTextName;
     private TextView mTextFingerprint;
     private ImageView mQRCode;
+    private View mLoading;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -57,6 +59,7 @@ protected void onCreate(Bundle savedInstanceState) {
         mTextName = findViewById(R.id.name);
         mTextFingerprint = findViewById(R.id.fingerprint);
         mQRCode = findViewById(R.id.qrcode);
+        mLoading = findViewById(R.id.loading);
     }
 
     @Override
@@ -83,8 +86,8 @@ protected void onStart() {
         mTextFingerprint.setText(PGP.formatFingerprint(fingerprint)
             .replaceFirst("  ", "\n"));
 
-        ViewUtils.getQRCodeBitmapAsync(this, mViewport, mQRCode,
-            PGP.createFingerprintURI(fingerprint));
+        ViewUtils.getQRCodeBitmapAsync(this, mViewport,
+            PGP.createFingerprintURI(fingerprint), this);
     }
 
     @Override
@@ -92,4 +95,15 @@ protected boolean isNormalUpNavigation() {
         return true;
     }
 
+    @Override
+    public void onQRCodeGenerated(Bitmap qrCode) {
+        mLoading.setVisibility(View.GONE);
+        mQRCode.setImageBitmap(qrCode);
+    }
+
+    @Override
+    public void onQRCodeError(Exception e) {
+        mLoading.setVisibility(View.GONE);
+        // TODO error
+    }
 }
diff --git a/app/src/main/java/org/kontalk/ui/RegisterDeviceActivity.java b/app/src/main/java/org/kontalk/ui/RegisterDeviceActivity.java
index 194d988dc..d59bebc1e 100644
--- a/app/src/main/java/org/kontalk/ui/RegisterDeviceActivity.java
+++ b/app/src/main/java/org/kontalk/ui/RegisterDeviceActivity.java
@@ -21,6 +21,7 @@
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.Intent;
+import android.graphics.Bitmap;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.view.View;
@@ -37,7 +38,7 @@
  * Shows the secure token for registering another device with the same key.
  * @author Daniele Ricci
  */
-public class RegisterDeviceActivity extends ToolbarActivity {
+public class RegisterDeviceActivity extends ToolbarActivity implements ViewUtils.OnQRCodeGeneratedListener {
     private static final String TAG = Kontalk.TAG;
 
     private View mViewport;
@@ -45,6 +46,7 @@ public class RegisterDeviceActivity extends ToolbarActivity {
     private TextView mTextServer;
     private TextView mTextToken;
     private ImageView mQRCode;
+    private View mLoading;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -58,6 +60,7 @@ protected void onCreate(Bundle savedInstanceState) {
         mTextServer = findViewById(R.id.servername);
         mTextToken = findViewById(R.id.token);
         mQRCode = findViewById(R.id.qrcode);
+        mLoading = findViewById(R.id.loading);
     }
 
     @SuppressLint("SetTextI18n")
@@ -81,8 +84,8 @@ protected void onStart() {
             mTextToken.setText(token);
         }
 
-        ViewUtils.getQRCodeBitmapAsync(this, mViewport, mQRCode,
-            generateTokenText(account, token, from));
+        ViewUtils.getQRCodeBitmapAsync(this, mViewport,
+            generateTokenText(account, token, from), this);
     }
 
     @Override
@@ -90,6 +93,18 @@ protected boolean isNormalUpNavigation() {
         return true;
     }
 
+    @Override
+    public void onQRCodeGenerated(Bitmap qrCode) {
+        mLoading.setVisibility(View.GONE);
+        mQRCode.setImageBitmap(qrCode);
+    }
+
+    @Override
+    public void onQRCodeError(Exception e) {
+        mLoading.setVisibility(View.GONE);
+        // TODO error
+    }
+
     /** This must match the parsing done in {@link #parseTokenText}. */
     private static String generateTokenText(String account, String token, String from) {
         return account + ";" + from + ";" + token;
diff --git a/app/src/main/java/org/kontalk/util/ViewUtils.java b/app/src/main/java/org/kontalk/util/ViewUtils.java
index 75cc66739..a64f8e224 100644
--- a/app/src/main/java/org/kontalk/util/ViewUtils.java
+++ b/app/src/main/java/org/kontalk/util/ViewUtils.java
@@ -28,6 +28,8 @@
 import com.google.zxing.qrcode.QRCodeWriter;
 import com.vanniktech.emoji.EmojiManager;
 
+import org.jivesoftware.smack.util.Async;
+
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.Color;
@@ -36,7 +38,6 @@
 import android.text.SpannableStringBuilder;
 import android.view.View;
 import android.view.ViewTreeObserver;
-import android.widget.ImageView;
 import android.widget.TextView;
 
 
@@ -56,9 +57,9 @@ public static int dp(Context context, float value) {
     /**
      * Waits for global layout to happen and set a QR code for the minimum size
      * between height and width of the given container. The QR code will be
-     * loaded automatically in {@code destination}.
+     * returned to the given listener.
      */
-    public static void getQRCodeBitmapAsync(final Context context, final View container, final ImageView destination, final String text) {
+    public static void getQRCodeBitmapAsync(final Context context, final View container, final String text, final OnQRCodeGeneratedListener listener) {
         // no need to handle memory leaks because the view tree observer
         // is created on every activity restart
         container.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@@ -71,14 +72,24 @@ public void onGlobalLayout() {
                     size = Math.min(displaySize.x, displaySize.y);
                 }
 
-                try {
-                    // TODO load in another thread
-                    Bitmap qrCode = getQRCodeBitmap(size, text);
-                    destination.setImageBitmap(qrCode);
-                }
-                catch (WriterException e) {
-                    // TODO set error image on destination
-                }
+                final int qrSize = size;
+                Async.go(new Runnable() {
+                    @Override
+                    public void run() {
+                        try {
+                            final Bitmap qrCode = getQRCodeBitmap(qrSize, text);
+                            container.post(new Runnable() {
+                                @Override
+                                public void run() {
+                                    listener.onQRCodeGenerated(qrCode);
+                                }
+                            });
+                        }
+                        catch (WriterException e) {
+                            listener.onQRCodeError(e);
+                        }
+                    }
+                });
             }
         });
     }
@@ -91,6 +102,11 @@ public static Bitmap getQRCodeBitmap(int size, String text) throws WriterExcepti
         return toBitmap(matrix);
     }
 
+    public interface OnQRCodeGeneratedListener {
+        void onQRCodeGenerated(Bitmap qrCode);
+        void onQRCodeError(Exception e);
+    }
+
     /**
      * Writes the given Matrix on a new Bitmap object.
      * http://codeisland.org/2013/generating-qr-codes-with-zxing/
diff --git a/app/src/main/res/layout/mykey_screen.xml b/app/src/main/res/layout/mykey_screen.xml
index 8e5366516..ff1d9bdab 100644
--- a/app/src/main/res/layout/mykey_screen.xml
+++ b/app/src/main/res/layout/mykey_screen.xml
@@ -69,6 +69,13 @@
                 android:layout_gravity="center_horizontal"
                 android:layout_marginTop="12dp" />
 
+            <me.zhanghai.android.materialprogressbar.MaterialProgressBar
+                android:id="@+id/loading"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:indeterminate="true"/>
+
         </LinearLayout>
     </ScrollView>
 </LinearLayout>
diff --git a/app/src/main/res/layout/register_device_screen.xml b/app/src/main/res/layout/register_device_screen.xml
index ad621740b..354ddf160 100644
--- a/app/src/main/res/layout/register_device_screen.xml
+++ b/app/src/main/res/layout/register_device_screen.xml
@@ -85,6 +85,13 @@
                 android:layout_gravity="center_horizontal"
                 android:layout_marginTop="12dp" />
 
+            <me.zhanghai.android.materialprogressbar.MaterialProgressBar
+                android:id="@+id/loading"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:indeterminate="true"/>
+
         </LinearLayout>
     </ScrollView>
 </LinearLayout>