fix errors when displaying empty table

gui/media_file_model.py

@@ -35,10 +35,7 @@ class MediaFileTableModel(QAbstractTableModel):
                 filter_rule += "WHERE "
             filter_rule += "review is true"
         print(f"{filter_rule=}")
-        try:
-            cursor.execute(f"SELECT id, url, review, should_download, file_name, cloud_link FROM media_file {filter_rule}")
-        except mariadb.Error as error:
-            print(error)
+        cursor.execute(f"SELECT id, url, review, should_download, file_name, cloud_link FROM media_file {filter_rule}")
         rows = cursor.fetchall()
         print(len(rows))
         if len(rows) > 0:
@@ -49,14 +46,13 @@ class MediaFileTableModel(QAbstractTableModel):
             self.endResetModel()
         else:
             self._data = None
-            try:
-                self.layoutChanged.emit()
-            except:
-                
+            self.layoutChanged.emit()
         self.main_window.statusBar.showMessage(f"{len(rows)} Einträge geladen", 3000)
 
     def rowCount(self, parent=QModelIndex()):
         # The length of the outer list.
+        if self._data is None:
+            return 0
         return len(self._data)
 
     def headerData(self, col, orientation, role=Qt.ItemDataRole.DisplayRole):
@@ -78,6 +74,8 @@ class MediaFileTableModel(QAbstractTableModel):
             return str(col+1)
 
     def data(self, index, role=Qt.ItemDataRole.DisplayRole):
+        if self._data is None:
+            return None
         value = self._data[index.row()][index.column()]
         if role == Qt.ItemDataRole.DisplayRole:
             if isinstance(value, datetime):
@@ -101,6 +99,8 @@ class MediaFileTableModel(QAbstractTableModel):
     def columnCount(self, index=QModelIndex()):
         # The following takes the first sub-list, and returns
         # the length (only works if all rows are an equal length)
+        if self._data is None:
+            return 5
         return len(self._data[0])
 
     def setData(self, index, value, role=Qt.ItemDataRole.EditRole):