allow clear of auto generated screenshot with clear checkbox

Author: yvess

django/gsmap/models.py

@@ -127,10 +127,12 @@ def data_changed(self, fields):
             if not self.pk or not self._old_values:
                 return True
 
+            changed_list = []
             for field in fields:
                 if getattr(self, field) != self._old_values[field]:
-                    return True
-                return False
+                    changed_list.append(True)
+                changed_list.append(False)
+            return any(changed_list)
         return True
 
     @property
@@ -189,7 +191,8 @@ def save_screenshot_handler(sender, **kwargs):
     def save_screenshot():
         post_save.disconnect(save_screenshot_handler, sender=Snapshot)
         instance = kwargs.get('instance')
-        if instance.data_changed(['data']): # only create snapshot if data changed
+        # only create snapshot if data changed
+        if instance.data_changed(['data', 'screenshot_generated', 'thumbnail_generated']):
             try:
                 # disconnect to break save recursive loop
                 post_save.disconnect(save_screenshot_handler, sender=Snapshot)

django/main/templates/admin/base_site.html

@@ -2,11 +2,7 @@
 
 {% block extrastyle %}
 <style>
-    #thumbnail_generated-clear_id, label[for='thumbnail_generated-clear_id'], #id_thumbnail_generated,
-    #screenshot_generated-clear_id, label[for='screenshot_generated-clear_id'], #id_screenshot_generated {
-        display: none;
-    }
-    .field-thumbnail_generated .clearable-file-input, .field-screenshot_generated .clearable-file-input {
+    #id_thumbnail_generated, #id_screenshot_generated {
         display: none;
     }
 </style>