I am searching for a simple dialog with a text entry widget asking the user for some input. The dialog should be easy to run (like the gtk.MessageDialog variant
There isn't one available in GTK+. You've got two options:
Something along the lines of:
#!/usr/bin/env python
import gtk
messagedialog = gtk.MessageDialog(parent=None, flags=0, type=gtk.MESSAGE_QUESTION, buttons=gtk.BUTTONS_OK, message_format="Hello")
action_area = messagedialog.get_content_area()
entry = gtk.Entry()
action_area.pack_start(entry)
messagedialog.show_all()
messagedialog.run()
messagedialog.destroy()
Though it does probably need more refinement to get the Entry to display nicely.