Statusbars are simple widgets used to
display a text message. They keep a stack of the messages pushed onto them,
so that popping the current message will re-display the previous text
message.
In order to allow different parts of an application to use the
same statusbar to display messages, the statusbar widget issues Context
Identifiers which are used to identify different "users". The message on top
of the stack is the one displayed, no matter what context it is in. Messages
are stacked in last-in-first-out order, not context identifier order.
A statusbar is created with a call to:
statusbar = gtk.Statusbar()
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A new Context Identifier is requested using a call to the following
method with a short textual description of the context:
context_id = statusbar.get_context_id(context_description)
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There are three additional methods that operate on
statusbars:
message_id = statusbar.push(context_id, text)
statusbar.pop(context_id)
statusbar.remove(context_id, message_id)
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The first, push(), is used to add a new
message to the statusbar. It returns a
message_id, which can be passed later to the
remove() method to remove the message with the
combination message_id and
context_id from the
statusbar's stack.
The pop() method removes the message
highest in the stack with the given
context_id.
The statusbar.py example
program creates a statusbar and two buttons, one for pushing items onto the
statusbar, and one for popping the last item back off.
Figure 9.9, “Statusbar Example” illustrates the result:
The statusbar.py source code is:
1 #!/usr/bin/env python
2
3 # example statusbar.py
4
5 import pygtk
6 pygtk.require('2.0')
7 import gtk
8
9 class StatusbarExample:
10 def push_item(self, widget, data):
11 buff = " Item %d" % self.count
12 self.count = self.count + 1
13 self.status_bar.push(data, buff)
14 return
15
16 def pop_item(self, widget, data):
17 self.status_bar.pop(data)
18 return
19
20 def __init__(self):
21 self.count = 1
22 # create a new window
23 window = gtk.Window(gtk.WINDOW_TOPLEVEL)
24 window.set_size_request(200, 100)
25 window.set_title("PyGTK Statusbar Example")
26 window.connect("delete_event", lambda w,e: gtk.main_quit())
27
28 vbox = gtk.VBox(False, 1)
29 window.add(vbox)
30 vbox.show()
31
32 self.status_bar = gtk.Statusbar()
33 vbox.pack_start(self.status_bar, True, True, 0)
34 self.status_bar.show()
35
36 context_id = self.status_bar.get_context_id("Statusbar example")
37
38 button = gtk.Button("push item")
39 button.connect("clicked", self.push_item, context_id)
40 vbox.pack_start(button, True, True, 2)
41 button.show()
42
43 button = gtk.Button("pop last item")
44 button.connect("clicked", self.pop_item, context_id)
45 vbox.pack_start(button, True, True, 2)
46 button.show()
47
48 # always display the window as the last step so it all splashes on
49 # the screen at once.
50 window.show()
51
52 def main():
53 gtk.main()
54 return 0
55
56 if __name__ == "__main__":
57 StatusbarExample()
58 main()
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