callbackEditFieldBug.patch

---
 src/GroceryCrud/Core/State/EditFormState.php | 3 ++-
 src/GroceryCrud/Core/State/ReadFormState.php | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/GroceryCrud/Core/State/EditFormState.php b/src/GroceryCrud/Core/State/EditFormState.php
index 1524f49..33b02e3 100644
--- a/src/GroceryCrud/Core/State/EditFormState.php
+++ b/src/GroceryCrud/Core/State/EditFormState.php
@@ -46,8 +46,9 @@ class EditFormState extends StateAbstract {
         $callbackEditFields = $this->gCrud->getCallbackEditFields();
 
         foreach ($callbackEditFields as $fieldName => $callback) {
+
             $outputData[$fieldName] =
-                !empty($outputData[$fieldName])
+                array_key_exists($fieldName, $outputData)
                     ? $callback($outputData[$fieldName], $this->getStateParameters()->primaryKeyValue)
                     : '';
         }
diff --git a/src/GroceryCrud/Core/State/ReadFormState.php b/src/GroceryCrud/Core/State/ReadFormState.php
index 65ffd78..de7bbc1 100644
--- a/src/GroceryCrud/Core/State/ReadFormState.php
+++ b/src/GroceryCrud/Core/State/ReadFormState.php
@@ -104,7 +104,7 @@ class ReadFormState extends StateAbstract {
 
         foreach ($callbackEditFields as $fieldName => $callback) {
             $outputData[$fieldName] =
-                !empty($outputData[$fieldName])
+                array_key_exists($fieldName, $outputData)
                     ? $callback($outputData[$fieldName], $this->getStateParameters()->primaryKeyValue)
                     : '';
         }
--