private AddCartItemDialog.CartItemListener cartItemListener = new AddCartItemDialog.CartItemListener() {
        @Override
        public void onOkClick(Product cartItem, int quantity) {

            realm.executeTransactionAsync(new Realm.Transaction() {
                @Override
                public void execute(Realm bgRealm) {

                    DraftInvoice draftInvoice = bgRealm.where(DraftInvoice.class).equalTo("shop.id", shopId).findFirst();


                    InvoiceItem invoiceItem = bgRealm.createObject(InvoiceItem.class);
                    invoiceItem.setPrice(cartItem.getPrice());
                    invoiceItem.setId(cartItem.getId());
                    invoiceItem.setQuantity(quantity);
                    invoiceItem.calculateTotal();

                    draftInvoice.getInvoiceItems().add(invoiceItem);

                    updateCartItemCount(draftInvoice.getInvoiceItems().size());
                }
            }, () -> {

            }, error -> {
                error.printStackTrace();
                Logger.e(error.getMessage());
            });

        }

        @Override
        public void onCancelClick() {

        }
    };

08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err: java.lang.IllegalStateException: Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at io.realm.BaseRealm.checkIfValid(BaseRealm.java:449)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at io.realm.ProductRealmProxy.realmGet$price(ProductRealmProxy.java:159)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at com.example.realshoptest.models.Product.getPrice(Product.java:75)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at com.example.realshoptest.NewInvoiceActivity$1$1.execute(NewInvoiceActivity.java:76)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at io.realm.Realm$1.run(Realm.java:1187)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at io.realm.internal.async.BgPriorityRunnable.run(BgPriorityRunnable.java:34)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
08-28 15:10:25.214 4996-4996/com.example.realshoptest W/System.err:     at java.lang.Thread.run(Thread.java:818)
08-28 15:10:25.214 4996-4996/com.example.realshoptest E/TestShopApp: Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.

public void onOkClick(Product cartItem, int quantity) {

realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm bgRealm) {

invoiceItem.setPrice(cartItem.getPrice());

public void onOkClick(Product cartItem, int quantity) {
        final long cartItemId = cartItem.getId();
        final String price = cartItem.getPrice();
        realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm bgRealm) {
                DraftInvoice draftInvoice = bgRealm.where(DraftInvoice.class).equalTo("shop.id", shopId).findFirst();
                InvoiceItem invoiceItem = bgRealm.createObject(InvoiceItem.class);
                invoiceItem.setPrice(price);
                invoiceItem.setId(cartItemId);

public void onOkClick(Product cartItem, int quantity) {
        final long cartItemId = cartItem.getId();
        realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm bgRealm) {
                Product product = bgRealm.where(Product.class).equalTo("id", cartItemId).findFirst();
                DraftInvoice draftInvoice = bgRealm.where(DraftInvoice.class).equalTo("shop.id", shopId).findFirst();
                InvoiceItem invoiceItem = bgRealm.createObject(InvoiceItem.class);
                invoiceItem.setPrice(product.getPrice());
                invoiceItem.setId(cartItemId);