填充 Glade 组合框“gtk_entry_set_text：断言 `text != NULL' 失败”？

Question

I am building a “pseudo-intelligent” GUI for a gimp plugin using Glade. The main part of the GUI has two frames and imports the contents using the “reparent” method. The main objective is to have the contents of the second frame determined by the selections made in the first frame. (Eventually, the intention is to import this GUI as the content for the tabbed pages of a "notebook")

To start with, I made a simple window, consisting of a “RadioButtonBox” and a “ComboBox” which is populated using:

# create the cell renderer
self.cell = gtk.CellRendererText()
#populate the default choice into the Selection  combobox
self.SelectionBox = self.builder.get_object("SelectionBox")
self.SelectionBox.set_model(self.EditCommands)
self.SelectionBox.pack_start(self.cell, True)
self.SelectionBox.add_attribute(self.cell, 'text', 1)
self.SelectionBox.set_active(0)
# End: populate the selection combo box section

This works and I can successfully “import” and “reparent” the simple GUI as the first frame of the larger, more complex GUI without any problems. However, as the design progressed, it has become more convenient to have the code for the first frame as an integral part of the main GUI, and this is where my problems begin.

I have reproduced the contents of the simple GUI in the first frame of the larger GUI and copy/pasted the code from the simple GUI's “ init ” function. In other-words, everything is identical.

Unfortunately, when I run the code I get the following error:

C:\Documents and Settings\anonymous\Desktop\Glade-tutorial\BatchEditMain\BatchEditLibrary\Tab.py:46: GtkWarning: gtk_entry_set_text: assertion `text != NULL' failed
  self.SelectionBox.set_active(0)

Could someone please explain what the problem is?

Thanks in advance

Irvine

Answer 1

The GTK Warning is saying that somewhere gtk_entry.set_text() is being called with None instead of some text. This is happening in the call to self.SelectionBox.set_active(0)

Answer 2

This feels a little bit like gravedigging , but i stumbled across the same Problem today and this was the first post google showed...

With a little further research i found this Question:

How create a combobox on Python with GTK3? The author seems to have the same error.

What in his and my case seems to do the trick is a simple:

combobox.set_entry_text_column(0)

Important it has to be in front of set_active(0) ! So in your case this would be:

...
self.SelectionBox.add_attribute(self.cell, 'text', 1)
self.SelectionBox.set_entry_text_column(0)
self.SelectionBox.set_active(0)
...

PS: Whatch out if you want to apply attributes like "foreground", they seem to get overwritten by set_entry_text_column(0) if set befor. Eg: if items in the model look like:

["TEXT_YOU_WANT_TO_DISPLAY","TEXT_FOREGROUNDCOLOR_AS_MARKUP_COLOR"]

The change to the foregroundcolor can be applied with the following:

...
self.SelectionBox.add_attribute(self.cell, 'text', 0)
self.SelectionBox.set_entry_text_column(0)
self.SelectionBox.add_attribute(self.cell, 'foreground', 1)
self.SelectionBox.set_active(0)
...