prevent cart update loop

Author: ajungg

CHANGELOG.md

@@ -1,6 +1,11 @@
 # Changelog  
 All notable changes to this project will be documented in this file.
 
+## [0.37.8]
+
+### Fixed
+- Only update cart when it actually changed
+
 ## [0.37.7]
 
 ### Added

build.gradle

@@ -31,7 +31,7 @@ allprojects {
     }
 
     project.ext {
-        sdkVersion='0.37.7'
+        sdkVersion='0.37.8'
         versionCode=1
 
         compileSdkVersion=30

core/src/main/java/io/snabble/sdk/ShoppingCart.java

@@ -137,13 +137,10 @@ void insert(Item item, int index, boolean update) {
             }
         }
 
-        addCount++;
-        modCount++;
-        generateNewUUID();
+
         items.add(index, item);
 
         clearBackup();
-
         checkLimits();
         notifyItemAdded(this, item);
 
@@ -162,6 +159,9 @@ void insert(Item item, int index, boolean update) {
         });
 
         if (update) {
+            addCount++;
+            modCount++;
+            generateNewUUID();
             invalidateOnlinePrices();
             updatePrices(true);
         }

core/src/main/java/io/snabble/sdk/ShoppingCartUpdater.java

@@ -27,6 +27,7 @@ class ShoppingCartUpdater {
     private Handler handler;
     private CheckoutApi.PaymentMethodInfo[] lastAvailablePaymentMethods;
     private boolean isUpdated;
+    private int successfulModCount = -1;
 
     ShoppingCartUpdater(Project project, ShoppingCart shoppingCart) {
         this.project = project;
@@ -56,6 +57,10 @@ public void update() {
         }
 
         final int modCount = cart.getModCount();
+        if (modCount == successfulModCount) {
+            return;
+        }
+
         Dispatch.mainThread(() -> checkoutApi.createCheckoutInfo(cart.toBackendCart(), null, new CheckoutApi.CheckoutInfoResult() {
             @Override
             public void success(final CheckoutApi.SignedCheckoutInfo signedCheckoutInfo, int onlinePrice, CheckoutApi.PaymentMethodInfo[] availablePaymentMethods) {
@@ -214,6 +219,8 @@ private void commitCartUpdate(int modCount, CheckoutApi.SignedCheckoutInfo signe
                 cart.setOnlineTotalPrice(checkoutInfo.price.price);
             }
 
+            successfulModCount = modCount;
+
             Logger.d("Successfully updated prices");
         } catch (Exception e) {
             Logger.e("Could not update price: %s", e.getMessage());