[gnome-devel-docs] tutorials python: new and improved buttonbox example and page

[Marta Maria Casetti <mmcasetti src gnome org>]

commit 41907a6d9d0355015d296f2933e5878b7372caf9
Author: Marta Maria Casetti <mmcasetti gmail com>
Date:   Thu Aug 16 18:59:13 2012 +0100

    tutorials python: new and improved buttonbox example and page

 platform-demos/C/buttonbox.py.page              |   14 ++-
 platform-demos/C/media/buttonbox_calculator.png |  Bin 5929 -> 10002 bytes
 platform-demos/C/samples/buttonbox.py           |  185 +++++++++++++++--------
 3 files changed, 136 insertions(+), 63 deletions(-)
---
diff --git a/platform-demos/C/buttonbox.py.page b/platform-demos/C/buttonbox.py.page
index cdff805..ee9d31d 100644
--- a/platform-demos/C/buttonbox.py.page
+++ b/platform-demos/C/buttonbox.py.page
@@ -21,7 +21,7 @@
   <title>ButtonBox</title>
 
   <media type="image" mime="image/png" src="media/buttonbox_calculator.png"/>
-  <p>Some labels in a grid.</p>
+  <p>A calculator - the buttons are enclosed in horizontal ButtonBoxes.</p>
 
   <links type="section" />
 
@@ -30,13 +30,25 @@
     <code mime="text/python" style="numbered"><xi:include href="samples/buttonbox.py" parse="text"><xi:fallback/></xi:include></code>
   </section>
 
+  <section id="methods">
+    <title>Uselful methods for a ButtonBox widget</title>
+    <list>
+      <item><p>The layout of the ButtonBox are set with <code>set_layout(layout)</code>, where <code>layout</code> can be <code>Gtk.ButtonBoxStyle.SPREAD</code> (buttons are evenly spread across the box), <code>Gtk.ButtonBoxStyle.EDGE</code> (buttons are placed at the edges of the box), <code>Gtk.ButtonBoxStyle.START</code> (buttons are grouped towards the start of the box), <code>Gtk.ButtonBoxStyle.END</code> (buttons are grouped towards the end of the box), <code>Gtk.ButtonBoxStyle.CENTER</code> (buttons are centered in the box).</p></item>
+      <item><p><code>set_child_secondary(button, is_secondary)</code> sets whether <code>button</code> should appear in a secondary group of children. A typical use of a secondary child is the help button in a dialog. This group appears after the other children if the style is <code>START</code>, <code>SPREAD</code> or <code>EDGE</code>, and before the other children if the style is <code>END</code>. If the style is <code>START</code> or <code>END</code>, then the secondary children are aligned at the other end of the button box from the main children. For the other styles, they appear immediately next to the main children.</p></item>
+      <item><p><code>set_child_non_homogeneous(button, is_non_homogeneous)</code> sets whether the child is exempted from homogeous sizing. Default value is <code>False</code>.</p></item>
+      <item><p><code>set_spacing(spacing)</code> sets the spacing, in pixels, between the buttons of the box.</p></item>
+    </list>
+  </section>
+
   <section id="references">
     <title>API References</title>
     <p>In this sample we used the following:</p>
     <list>
       <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkButtonBox.html";>GtkButtonBox</link></p></item>
+      <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkBox.html";>GtkBox</link></p></item>
       <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkButton.html";>GtkButton</link></p></item>
       <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkEntry.html";>GtkEntry</link></p></item>
+      <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkGrid.html";>GtkGrid</link></p></item>
     </list>
   </section>
 </page>
diff --git a/platform-demos/C/media/buttonbox_calculator.png b/platform-demos/C/media/buttonbox_calculator.png
index f110c4d..a82e7a5 100644
Binary files a/platform-demos/C/media/buttonbox_calculator.png and b/platform-demos/C/media/buttonbox_calculator.png differ
diff --git a/platform-demos/C/samples/buttonbox.py b/platform-demos/C/samples/buttonbox.py
index 1ed7872..484910e 100644
--- a/platform-demos/C/samples/buttonbox.py
+++ b/platform-demos/C/samples/buttonbox.py
@@ -4,82 +4,134 @@ import sys
 class MyWindow(Gtk.ApplicationWindow):
     def __init__(self, app):
         Gtk.Window.__init__(self, title="Calculator", application=app)
-        self.set_default_size(450, 100)
+        self.set_default_size(350, 200)
         self.set_border_width(10)
 
-        box = Gtk.ButtonBox.new(Gtk.Orientation.HORIZONTAL)
-        
-        button_plus = Gtk.Button(label="+")
-        button_plus.connect("clicked", self.plus_callback)
-        box.add(button_plus)
-
-        button_minus = Gtk.Button(label="-")
-        button_minus.connect("clicked", self.minus_callback)
-        box.add(button_minus)
-
-        button_multi = Gtk.Button(label="*")
-        button_multi.connect("clicked", self.multi_callback)
-        box.add(button_multi)
+        # an entry
+        self.entry = Gtk.Entry()
+        # with an initial text
+        self.entry.set_text('0')
+        # text aligned on the right
+        self.entry.set_alignment(1)
+        # the text in the entry cannot be modified writing in it
+        self.entry.set_can_focus(False)
+
+        # a grid
+        grid = Gtk.Grid()
+        grid.set_row_spacing(5)
         
-        button_divided = Gtk.Button(label="/")
-        button_divided.connect("clicked", self.divided_callback)
-        box.add(button_divided)
+        # to attach the entry
+        grid.attach(self.entry, 0, 0, 1, 1)
         
-        button_equal = Gtk.Button(label="=")
-        button_equal.connect("clicked", self.equal_callback)
-        box.add(button_equal)
-                
-        button_cancel = Gtk.Button(label="C")
-        button_cancel.connect("clicked", self.cancel_callback)
-        box.add(button_cancel)
+        # the labels for the buttons
+        buttons = [ 7, 8, 9, '/',
+                    4, 5, 6, '*',
+                    1, 2, 3, '-',
+                    'C', 0, '=', '+' ]
         
-        box.set_child_non_homogeneous(button_cancel, True)
-              
-        self.entry = Gtk.Entry()
-        self.entry.set_text('0.0')
-        self.entry.connect("activate", self.equal_callback)
-
-        self.second_number = 0.0
-        self.result = 0.0
-
+        # each row is a ButtonBox, attached to the grid            
+        for i in range(4):
+            hbox = Gtk.ButtonBox.new(Gtk.Orientation.HORIZONTAL)
+            hbox.set_spacing(5)
+            grid.attach(hbox, 0, i + 1, 1, 1)
+            # each ButtonBox has 4 buttons, connected to the callback function
+            for j in range(4):
+                button = Gtk.Button(label=buttons[i * 4 + j])
+                button.set_can_focus(False)
+                button.connect("clicked", self.button_clicked)
+                hbox.add(button)
+            
+        # some variables for the calculations
+        self.first_number = 0
+        self.result = 0
+        self.counter = 0
         self.operation = ""
 
-        grid = Gtk.Grid()
-        grid.attach(self.entry, 0, 0, 1, 1)
-        grid.attach(box, 0, 1, 1, 1)
-        
+        # add the grid to the window
         self.add(grid)
-        
+
+    # callback function for all the buttons
+    def button_clicked(self, button):
+        # functions for the operations
+        if button.get_label() == '+':            
+            self.plus_callback(button)
+        elif button.get_label() == '-':
+            self.minus_callback(button)
+        elif button.get_label() == '*':
+            self.multi_callback(button)
+        elif button.get_label() == '/':
+            self.divided_callback(button)
+        # for =
+        elif button.get_label() == '=':
+            self.equal_callback(button)
+        # for Cancel
+        elif button.get_label() == 'C':
+            self.cancel_callback(button)
+        # for a digit button
+        else:
+            new_digit = int(button.get_label())
+            if self.entry.get_text() == 'error':
+                number = 0
+            else:
+                number = int(self.entry.get_text())
+            number = number * 10 + new_digit
+            self.entry.set_text(str(number))
+
+    # to calculate +
     def plus_callback(self, button):
-        if self.entry.get_text() == "":
-            self.first_number = 0.0
+        self.counter += 1
+        if self.counter == 1:
+            self.first_number = int(self.entry.get_text())
         else:
-            self.first_number = float(self.entry.get_text())
+            self.second_number = int(self.entry.get_text())
+            self.first_number = self.first_number + self.second_number
+        self.entry.set_text('0')
         self.operation = "plus"
-
+        
+    # to calculate -
     def minus_callback(self, button):
-        if self.entry.get_text() == "":
-            self.first_number = 0.0
+        self.counter += 1
+        if self.counter == 1:
+            self.first_number = int(self.entry.get_text())
         else:
-            self.first_number = float(self.entry.get_text())
+            self.second_number = int(self.entry.get_text())
+            self.first_number = self.first_number - self.second_number
+        self.entry.set_text('0')
         self.operation = "minus"
 
+    # to calculate *
     def multi_callback(self, button):
-        if self.entry.get_text() == "":
-            self.first_number = 0.0
+        self.counter += 1
+        if self.counter == 1:
+            self.first_number = int(self.entry.get_text())
         else:
-            self.first_number = float(self.entry.get_text())
+            self.second_number = int(self.entry.get_text())
+            self.first_number = self.first_number * self.second_number
+        self.entry.set_text('0')
         self.operation = "multiplication"
 
+    # to calculate /
     def divided_callback(self, button):
-        if self.entry.get_text() == "":
-            self.first_number = 0.0
+        self.counter += 1
+        if self.counter == 1:
+            self.first_number = int(self.entry.get_text())
         else:
-            self.first_number = float(self.entry.get_text())
+            self.second_number = int(self.entry.get_text())
+            try:
+                self.first_number = self.first_number / self.second_number
+            except ZeroDivisionError:
+                self.cancel_callback(button)
+                self.entry.set_text("error")
+                self.first_number = 0
+                self.second_number = 0
+                self.counter = 0
+                return
+        self.entry.set_text('0')
         self.operation = "division"
 
+    # to return a result (=)
     def equal_callback(self, button):
-        self.second_number =  float(self.entry.get_text())
+        self.second_number =  int(self.entry.get_text())
         if self.operation == "plus":
             self.result = self.first_number + self.second_number
         elif self.operation == "minus":
@@ -87,21 +139,30 @@ class MyWindow(Gtk.ApplicationWindow):
         elif self.operation == "multiplication":
             self.result = self.first_number * self.second_number
         elif self.operation == "division":
-            self.result = self.first_number / self.second_number
+            try:
+                self.result = self.first_number / self.second_number
+            except ZeroDivisionError:
+                self.cancel_callback(button)
+                self.entry.set_text("error")
+                self.first_number = 0
+                self.second_number = 0
+                self.counter = 0
+                return
         else:
-            print "Error!"
+            self.result = 0
         self.first_number = self.result
+        self.second_number = 0
+        self.counter = 0
         self.entry.set_text(str(self.result))
 
+    # to cancel the operation
     def cancel_callback(self, button):
-        if self.entry.get_text() == "":
-            self.first_number = 0.0
-        else:
-            self.first_number = float(self.entry.get_text())
-        self.second_number = 0.0
-        self.result = 0.0
-        self.entry.set_text('0.0')
-
+        self.first_number = 0
+        self.second_number = 0
+        self.result = 0
+        self.counter = 0
+        self.entry.set_text('0')
+    
 class MyApplication(Gtk.Application):
     def __init__(self):
         Gtk.Application.__init__(self)