Checkboxes and Radio Buttons in wxPython (
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In this article, we will focus on two basic controls and a few relatives: checkboxes and radio buttons. Both controls give the user a variety of options and yet him or her choose anywhere from one to all of them.This article assumes that you have basic knowledge of wxPython – how to create a frame, populate it with controls and organize them. Make sure you understand these tasks before you dive into this article.
wxCheckBox
Checkboxes are useful in applications. Besides looking nice and neat, they can be used for more than one purpose. For example, in one application, checkboxes could allow a user to select all the items that apply, and in another application, checkboxes could give the user the option to turn things on and off. They are also very easy to work with and aren't over-complicated by too many methods and events.
Let's take a look at a very simple application that uses checkboxes to gather input from the user:
from wxPython.wx import *
class Window ( wxFrame ):
def __init__ ( self ):
wxFrame.__init__ ( self, None, -1, 'Survey', size = ( 400, 200 ) )
# Create a panel to house everything
self.panel = wxPanel ( self, -1 )
# Create a wxGridBagSizer to organize our widgets
self.sizer = wxGridBagSizer ( 5, 5 )
# Create a label for our application
self.label = wxStaticText ( self.panel, -1, 'What electronics do you plan to buy in the next year?' + \
'\nCheck all that apply.', style = wxTE_CENTER )
# Create a few wxCheckBox instances
self.camera = wxCheckBox ( self.panel, -1, 'Digital Camera' )
self.music = wxCheckBox ( self.panel, -1, 'Music-related Device' )
self.hardware = wxCheckBox ( self.panel, -1, 'Computer Hardware' )
self.television = wxCheckBox ( self.panel, -1, 'Television' )
self.dvd = wxCheckBox ( self.panel, -1, 'DVDPlayer' )
self.other = wxCheckBox ( self.panel, -1, 'Other' )
# Create a button
self.button = wxButton ( self.panel, 100, 'Submit' )
# Catch a click to the button
EVT_BUTTON ( self.panel, 100, self.submit )
# Add everything to the sizer
self.sizer.Add ( self.label, ( 0, 0 ), ( 1, 3 ), wxALIGN_CENTER )
self.sizer.Add ( self.camera, ( 1, 0 ) )
self.sizer.Add ( self.music, ( 1, 1 ) )
self.sizer.Add ( self.hardware, ( 1, 2 ) )
self.sizer.Add ( self.television, ( 2, 0 ) )
self.sizer.Add ( self.dvd, ( 2, 1 ) )
self.sizer.Add ( self.other, ( 2, 2 ) )
self.sizer.Add ( self.button, ( 3, 0 ), ( 1, 3 ), wxALIGN_CENTER )
# Center everything
self.horizontal = wxBoxSizer ( wxHORIZONTAL )
self.horizontal.Add ( ( 0, 0 ), 1 )
self.horizontal.Add ( self.sizer )
self.horizontal.Add ( ( 0, 0 ), 1 )
self.vertical = wxBoxSizer ( wxVERTICAL )
self.vertical.Add ( ( 0, 0, ), 1 )
self.vertical.Add ( self.horizontal, 0, wxALIGN_CENTER )
self.vertical.Add ( ( 0, 0 ), 1 )
# Attach the sizer to the panel
self.panel.SetSizerAndFit ( self.vertical )
self.Show ( True )
# This method is triggered when the button is clicked
# It checks whether or not each checkbox is clicked
def submit ( self, event ):
message = 'You plan to get the following items in the next year:'
# Check whether or not each checkbox is clicked
# If one is, add a string to the message variable
if self.camera.GetValue():
message = message + '\nDigital Camera'
if self.music.GetValue():
message = message + '\nMusic-related Device'
if self.hardware.GetValue():
message = message + '\nComputer Hardware'
if self.television.GetValue():
message = message + '\nTelevision'
if self.dvd.GetValue():
message = message + '\nDVD Player'
if self.other.GetValue():
message = message + '\nOther'
# Display a dialog with the results
dialog = wxMessageDialog ( self, message, 'Results', style = wxOK )
dialog.ShowModal()
dialog.Destroy()
application = wxPySimpleApp()
Window()
application.MainLoop()
It is also possible to catch a click on a checkbox and set the value of the checkbox. We'll create a simple application that combines both of these functions:
from wxPython.wx import *
class Window ( wxFrame ):
def __init__ ( self ):
wxFrame.__init__ ( self, None, -1, 'Checkbox Test', size = ( 200, 200 ) )
# Create a panel
self.panel = wxPanel ( self, -1 )
# Create a vertical sizer
self.vertical = wxBoxSizer ( wxVERTICAL )
# Add a space
self.vertical.Add ( ( 0, 0 ), 1 )
# Create and add two checkboxes
self.first = wxCheckBox ( self.panel, 1, 'First' )
self.second = wxCheckBox ( self.panel, 2, 'Second' )
self.vertical.Add ( self.first, 0, wxALIGN_CENTER )
self.vertical.Add ( ( 5, 5 ), 0 )
self.vertical.Add ( self.second, 0, wxALIGN_CENTER )
# Catch events
EVT_CHECKBOX ( self.panel, 1, self.firstHandle )
EVT_CHECKBOX ( self.panel, 2, self.secondHandle )
# Add another space
self.vertical.Add ( ( 0, 0 ), 1 )
# Center it with a horizontal sizer
self.horizontal = wxBoxSizer ( wxHORIZONTAL )
self.horizontal.Add ( ( 0, 0 ), 1 )
self.horizontal.Add ( self.vertical, 0, wxALIGN_CENTER )
self.horizontal.Add ( ( 0, 0 ), 1 )
# Add the sizer
self.panel.SetSizerAndFit ( self.horizontal )
self.Show ( True )
# This method unchecks the other checkbox if it is checked
def firstHandle ( self, event ):
self.second.SetValue ( False )
# This method does the same thing
def secondHandle ( self, event ):
self.first.SetValue ( False )
application = wxPySimpleApp()
Window()
application.MainLoop()
A normal checkbox has two states. It is possible, however, to create a checkbox with three states:
from wxPython.wx import *
class Window ( wxFrame ):
def __init__ ( self ):
wxFrame.__init__ ( self, None, -1, 'Checkbox Test', size = ( 200, 200 ) )
# Create a panel
self.panel = wxPanel ( self, -1 )
# Create a checkbox with three states
self.checkbox = wxCheckBox ( self.panel, 1, 'Tri-state border', style = wxCHK_3STATE | wxCHK_ALLOW_3RD_STATE_FOR_USER )
# Catch a click
EVT_CHECKBOX ( self.panel, 1, self.handle )
self.Show ( True )
# Handle a click event
def handle ( self, event ):
# Print the value of the checkbox
print self.checkbox.Get3StateValue()
application = wxPySimpleApp()
Window()
application.MainLoop()
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