just test

app/src/main/java/com/example/yourcashiertest/activities/CartActivity.java

@@ -81,9 +81,9 @@ public class CartActivity extends AppCompatActivity {
         });
 
         adapter.setCartListener(new CartAdapter.CartListener() {
-
             @Override
             public void onIncrease(Cart cart) {
+                ProductViewModel productViewModel = new ProductViewModel(getApplication());
                 Product dbProduct = DBHelper.getProductById(getApplicationContext(), (int) cart.getIdProduct());
                 cart.setQty(cart.getQty() + 1);
                 cart.setPrice(cart.getRealPrice() * cart.getQty());

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

@@ -122,7 +122,7 @@
             app:layout_constraintTop_toBottomOf="@+id/tv_user"
             app:layout_constraintVertical_bias="0.48000002"
             tools:layout_editor_absoluteX="16dp"
-            android:hint="Cari pushProduct ... "
+            android:hint="Search Product"
             android:imeOptions="actionSearch"
             android:inputType="textCapWords"
             android:textSize="@dimen/text_default" />