Simple GUI using Gtk Builder and Glade3

Getting StartedRequirementsTo start with I’m using Ubuntu10.04and yes it is a little dated but I use it because I’m involved with LinuxCNC software and that is the latest version supported by the real time kernel.Installing Glade3From the Ubuntu menu Applications>Ubuntu Software Center type in glade in the search bar to bring up the GTK+2User Interface Builder.Click on more info and at the bottom you will see what version of Glade it is.Install if version is3.x and it will be on the Applications> Programming menu.I have Glade3.6.7installed and Python2.6.5so these versions or anything newer should work. You can check your Python version by opening up a terminal and typing inpython--version.When you run Glade just look in Help>AboutFirst Glade ProjectRun Glade3and the first screen you will see is the Project Preferences.We are using GtkBuilder and not the outdated Libglad so you can just accept the defaults in the preferences screen and close it.Now you have an empty project.Press F1to bring up the help menu then select Getting Started.Notice what each section of the Glade3Interface is called.First thing we need is a window so from the Palette>Toplevels click on the window and that will add a top level window to your project.Your project should look like this now.From the Palette>Containers click on the vertical box,then click in the window and leave the number at three in the pop up.Your project should look like this now.Now we will add a Menu Bar to the top section of the vertical box from the Containers,a label tothe middle of the vertical box from the Control and Displaysection of the Palette and a status bar to the bottom section of the vertical box from the Control and Display section.And just accept the default of3items as I don’t think that really does anything.Your project should look like this now.Now we need to create a signal from the Quit on the menu.The default name for Quit is imagemenuitem5which is a bit cryptic so we will change that to gtk_quit.In the Inspector click on imagemenuitem5then in the General tab of the Properties dialog change the Name:to gtk_quit. Your project should look like this now.Now in the Signals tab of the Properties dialog under GtkMenuItem in the Handler column clickon the<Type here>next to the activate Signal.From the drop down box selecton_gtk_quit_activate then press Enter.If you don’t press the Enter key the selection will not be saved!Your project should look like this now.Next we need to create a signal from the main window if someone clicks on the X in the corner to close the window.Click on window1in the Inspector then theSignals tab and then GtkObject and for the destroy signal handler select on_window1_destroy.Again don’t forget to press the Enter key after making the selection.Your project should look like this now.Ok,that’s it for the Glade3part of this tutorial.Save your Glade file as tutorial-1.glade to an empty directory and don’t forget to type in the.glade extension as it is not automagiclly added. You can close the Glade designer now.The PythonThe python code was short and sweet so lets examine what each part is for.Executable PathThe#!/usr/bin/env python line will use the installed python that appears in the$PATH.This is how you make the file executable without having to type in python then the file name to run the file.If you opened up a terminal and changed directories to the location of your python file you would use./tutorial-1.py to run the file.The./means execute the file in this directory,without this Linux will search the normal installed locations for an executable named tutorial-1.py.An alternate method is to use python tutorial-1.py to run the ing this method the file need not be set to executable and doesn’t need the#!/usr/bin/env pythonline.Set the path to Python#!/usr/bin/env pythonImport LibrariesNext we need to import some libraries and make sure we are using pygtk2.0.If gtk failed to import the except:would be run and the print statement would print to the terminal the error message then execution of the program would abort.Import the Gtk Libraryimport gtkMain ClassThink of a class as a blueprint.It doesn’t do anything itself,it simply describes how to make something.You can create objects from a class,known technically as aninstance of the class. Next we create the main class that is called when we run the program.It can be named just about anything but reserved key words in Python.If your an old movie fan you know what Buglump means…The Buglump Class#we can call it just about anything we wantclass Buglump:#This first define is for our on_window1_destroy signal we created in the#Glade designer.The print message does just that and prints to the terminal#which can be useful for debugging.The'object'if you remember is the signal#class we picked from GtkObject.def on_window1_destroy(self,object,data=None):print"quit with cancel"gtk.main_quit()#This is the same as above but for our menu item.def on_gtk_quit_activate(self,menuitem,data=None):print"quit from menu"gtk.main_quit()#This is our init part where we connect the signalsdef__init__(self):self.gladefile="tutorial-1.glade"#store the file nameself.builder=gtk.Builder()#create an instance of the gtk.Builderself.builder.add_from_file(self.gladefile)#add the xml file to the Builder#This line does the magic of connecting the signals created in the Glade3#builder to our defines above.You must have one def for each signal if#you use this line to connect the signals.self.builder.connect_signals(self)self.window=self.builder.get_object("window1")#This gets the'window1'objectself.window.show()#this shows the'window1'objectCreate an Instance#If this is run stand alone execute the following after the'if'#If this class is imported into another program the code after the'if'will#not run.This makes the code more flexible.if__name__=="__main__":main=Buglump()#create an instance of our classgtk.main()#run the darn thingThe PythonThe following code is the complete python file.In the same directory as the glade1.glade file was saved save the following python code as glade1.py.glade1.py#!/usr/bin/env pythonimport gtkclass Buglump:def on_window1_destroy(self,object,data=None):print"quit with cancel"gtk.main_quit()def on_gtk_quit_activate(self,menuitem,data=None):print"quit from menu"gtk.main_quit()def__init__(self):self.gladefile="tutorial-1.glade"self.builder=gtk.Builder()self.builder.add_from_file(self.gladefile)self.builder.connect_signals(self)self.window=self.builder.get_object("window1")self.window.show()if__name__=="__main__":main=Buglump()gtk.main()View the ResultsNow open up a terminal and cd to the directory where your files are.Type ls to see the contents of the directory.You should see your file names in black.Now type python glade1.py or./glade1.py and our screen pops up…Not much to look at but if you select Quit from the file menu it magically disappears and in the terminal a message is printed.。