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pythonwxpythonwxwidgets

The order of wxPython events is causing me problems

My GUI consists of a wx.ListCtrl on the left, with a list of objects to edit, and a set of wx.TextCtrls on the right, for editing the selected object.

My strategy for implementing this was:

  • On a textbox's wx.EVT_KILL_FOCUS , update the relevant attribute of the currently selected object
  • On the list's wx.EVT_LIST_ITEM_DESELECTED, either hide the textboxes or blank them out and disable them (needed for when the user clicks the blank space in the list control)
  • On the list's wx.EVT_LIST_ITEM_SELECTED, populate the text controls with the values of the selected object's attributes

With this setup, there are 3 use cases, and 2 of them work:

  1. When the user is clicking/tabbing between textboxes, the correct wx.EVT_KILL_FOCUSs occur, and the attributes get updated.

  2. When the user clicks from a textbox into the blank space in the list, that's OK as well: first wx.EVT_KILL_FOCUS causes the attribute to update, and then wx.EVT_LIST_ITEM_DESELECTED hides the textboxes.

  3. The problem is when the user clicks directly from a textbox to another object in the list control. The order of events in this case is wx.EVT_LIST_ITEM_DESELECTED, wx.EVT_LIST_ITEM_SELECTED, and then finally wx.EVT_KILL_FOCUS. You can probably see the problem: by the time the method that updates attributes is called, a new object has already been selected and the textboxes have been populated with new values.

So I know exactly what the problem is, but I can't come up with a nice, clean way to fix it. Ideally I'd like to be able to change the order of the wx events (putting wx.EVT_KILL_FOCUS at the front), but I doubt that's possible. Is there some other obvious solution I'm missing?

Solution

  • wx.EVT_LIST_ITEM_DESELECTED will only fire when the user changes the selected object in the list box. This serves the same purpose as losing focus on the text box. Call the update routines from that event as well. To skip the subsequent wx.EVT_KILL_FOCUS from the text box set a "isDirty" attribute in the parent object after you update the attributes. You can check the isDirty value anytime to confirm there are changes to commit. This attribute would have to be reset when you populate the text boxes for the new selection and then set during other textbox events.