Fixed crash if buying when no listener was set

extension-iap/src/iap_android.cpp

@@ -244,6 +244,12 @@ JNIEXPORT void JNICALL Java_com_defold_iap_IapJNI_onPurchaseResult__ILjava_lang_
 
 static void HandleProductResult(const IAPCommand* cmd)
 {
+    if (cmd->m_Callback == 0)
+    {
+        dmLogWarning("Received product list but no listener was set!");
+        return;
+    }
+
     lua_State* L = dmScript::GetCallbackLuaContext(cmd->m_Callback);
     int top = lua_gettop(L);
 
@@ -289,6 +295,12 @@ static void HandleProductResult(const IAPCommand* cmd)
 
 static void HandlePurchaseResult(const IAPCommand* cmd)
 {
+    if (cmd->m_Callback == 0)
+    {
+        dmLogWarning("Received purchase result but no listener was set!");
+        return;
+    }
+
     lua_State* L = dmScript::GetCallbackLuaContext(cmd->m_Callback);
     int top = lua_gettop(L);
 

extension-iap/src/java/com/defold/iap/IapGooglePlay.java

@@ -67,7 +67,7 @@ public class IapGooglePlay implements Handler.Callback {
     private boolean autoFinishTransactions;
 
     private static interface ISkuRequestListener {
-    	public void onProducts(int resultCode, JSONObject products);
+        public void onProducts(int resultCode, JSONObject products);
     }
 
     private static class SkuRequest {

extension-iap/src/java/com/defold/iap/IapGooglePlayActivity.java

@@ -69,8 +69,8 @@ public class IapGooglePlayActivity extends Activity {
     }
 
     private void buy(String product, String productType) {
-    	// Flush any pending items, in order to be able to buy the same (new) product again
+        // Flush any pending items, in order to be able to buy the same (new) product again
-    	processPendingConsumables();
+        processPendingConsumables();
 
         try {
             Bundle buyIntentBundle = service.getBuyIntent(3, getPackageName(), product, productType, "");