#format wiki
#language en
#pragma section-numbers off

= Swing Examples in Jython =

DocumentationAndEducation

<<TableOfContents>>

----

Using Java Swing with Jython is a lot of fun and makes it really easy to develop a nice UI in much less code then a similar Java app. All of the examples below work with Jython 2.2 and a 1.5 (or greater) JVM is strongly recommended.

Many of these have been tested and will work using jdk/jre <1.5. If you are using an older JVM will need to change the code from ''frame.add'' to ''frame.contentPane.add'' 

Below there are several examples that cover various swing components. Some time in the past I found a Jython script on the Georgia Tech web site that showed off a number of components, being that the web is constantly changing I have provided a copy of the SwingSampler with the permission of the professor who believes he is the author.

In March 2007, Anton Vredegoor asked the Jython mailing list for help converting [[http://leepoint.net/notes-java/examples/components/editor/nutpad.html|Java Simple Editor]] and Jeff Emanuel provided complete conversion to Jython. Here is the JythonNutpad that was posted.

The Jython Mailing list is a great source of help. If you have questions or problems the mailing list is a good place to look for help but there is no substitute for RTFM or Google searches before hand. 

== Simple Swing examples ==

These are fairly simple examples but show components.

=== Hello, World! ===

These are some ways of creating a simple frame with the title 'Hello, World!' on it.

{{{#!python

from javax.swing import JFrame
JFrame('Hello, World!', defaultCloseOperation=JFrame.EXIT_ON_CLOSE, size=(300, 300), locationRelativeTo=None).setVisible(True)}}}

{{{#!python

from javax.swing import JFrame
f = JFrame('Hello, World!', defaultCloseOperation=JFrame.EXIT_ON_CLOSE, size=(300, 300), locationRelativeTo=None)
f.setVisible(True)}}}

The above examples can also be done "Java-style", i.e. a bit more verbose as shown below:

{{{#!python

from javax.swing import JFrame
f = JFrame('Hello, World!')
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
f.setSize(300, 300)
f.setLocationRelativeTo(None)
f.setVisible(True)}}}

And yet another way of doing it is shown below:

{{{#!python

from javax.swing import JFrame
f = JFrame('Hello, World!')
f.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
f.size = (300, 300)
f.locationRelativeTo = None
f.visible = True}}}


=== JButton and Button events ===
Just a simple example.
 
{{{#!python
"""
A simple example that shows button event handling

Greg Moore
Sept 2007
"""

from javax.swing import *
from java.awt import BorderLayout

class Example:
  def setText(self,event):
      self.label.text = 'Button clicked.'

  def __init__(self):
    frame = JFrame("Jython Example JButton")
    frame.setSize(100, 100)
    frame.setLayout(BorderLayout())
    self.label = JLabel('Hello from Jython')
    frame.add(self.label, BorderLayout.NORTH)
    button = JButton('Click Me',actionPerformed=self.setText)
    frame.add(button, BorderLayout.SOUTH)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setVisible(True)

if __name__ == '__main__':
	Example()
}}}

=== JTextField ===

{{{#!python
"""
Swing JTextField example in Jython.

Creates 2 text fields and clicking the button copies text in one textfield
to the other. 

Greg Moore
Sept 2007
"""

from javax.swing import *
from java.lang import *

class Example:

  def copyText(self,event):
      self.textfield2.text = self.textfield1.text

  def __init__(self):
	# These lines setup the basic frame, size.
	# the setDefaultCloseOperation is required to completely exit the app
	# when you click the close button
    frame = JFrame("Jython JText Field Example")
    frame.setSize(200, 150)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)

    # Create Panel and add swing components and show it.
    pnl = JPanel()
    frame.add(pnl)
    self.textfield1 = JTextField('Type something here',15)
    pnl.add(self.textfield1)
    self.textfield2 = JTextField('and click Copy', 15)
    pnl.add(self.textfield2)
    copyButton = JButton('Copy',actionPerformed=self.copyText)
    pnl.add(copyButton)
    frame.pack()
    frame.setVisible(True)

if __name__ == '__main__':
  #start things off.
  Example()
}}}

=== JRadioButton ===


{{{#!python
"""
Swing JRadioButton example in Jython.

Creates radio buttons and event handler

Greg Moore
Sept 2007
"""

# Using import * is bad form but since this is just a example I'll take the
# easy way out instead of specifing each package.
from javax.swing import *
from java.awt import *


class RadioButtonExample:
  def radioBtnbCheck(self,event):
    # Process the events and update the label
    statusText = ""
    if self.radioBtn1.isSelected():
      statusText = "Radio Button 1 is selected "
    if self.radioBtn2.isSelected():
      statusText = statusText + "Radio Button 2 is selected "
    self.rbStatusLabel.text = statusText

  def __init__(self):
	# These lines setup the basic frame, size and layout
	# the setDefaultCloseOperation is required to completely exit the app
	# when you click the close button
    frame = JFrame("Jython Example JRadioButton")
    frame.setSize(400, 150)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setLayout(BorderLayout())

    # create 2 panels the top one containing radio buttons and the bottom one
    # has the label and button. add them to the frame and show it.
    rbPanel = JPanel()
    frame.add(rbPanel,BorderLayout.NORTH)
    self.radioBtn1 = JRadioButton('Radio Button 1')
    self.radioBtn2 = JRadioButton('Radio Button 2')
    rbPanel.add(self.radioBtn1)
    rbPanel.add(self.radioBtn2)
    rbBtnGroup = ButtonGroup()
    rbBtnGroup.add(self.radioBtn1)
    rbBtnGroup.add(self.radioBtn2)

    panel = JPanel()
    panel.setLayout(BorderLayout())
    frame.add(panel,BorderLayout.SOUTH)
    button = JButton('Check',actionPerformed=self.radioBtnbCheck)
    panel.add(button,BorderLayout.WEST)
    self.rbStatusLabel =JLabel()
    panel.add(self.rbStatusLabel,BorderLayout.EAST)
    frame.pack()
    frame.setVisible(True)

if __name__ == '__main__':
  #start things off.
  RadioButtonExample()
}}}

=== JCheckBox ===

{{{#!python
"""
Swing JCheckBox example in Jython.

Creates a couple checkboxes and and event handler

Greg Moore
Sept 2007
"""

# Using import * is bad form but since this is just a example I'll take the
# easy way out instead of specifing each package.
from javax.swing import *
from java.awt import *

class CheckBoxExample:

  def cbEvents(self,event):
  	# Process the events and update the label
    cbStatusMsg=""
    if self.chkbox1.isSelected():
      cbStatusMsg = "checkbox1 is selected "
    if self.chkbox2.isSelected():
      cbStatusMsg = cbStatusMsg + "checkbox2 is selected"
    self.cbStatusLabel.text = cbStatusMsg

  def __init__(self):
	# These lines setup the basic frame, size and layout
	# the setDefaultCloseOperation is required to completely exit the app
	# when you click the close button
	frame = JFrame("Jython JCheckBox Example")
	frame.setLayout(BorderLayout())
	frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
	
	# this could be done with only one JPanel or use different layout
	# create a panel for the checkboxes
	cbPanel = JPanel()
	frame.add(cbPanel,BorderLayout.NORTH)
	self.chkbox1 = JCheckBox('checkbox 1')
	self.chkbox2 = JCheckBox('checkbox 2')
	cbPanel.add(self.chkbox1)
	cbPanel.add(self.chkbox2)

	# create a second panel with the button and label
	panel = JPanel()
	panel.setLayout(BorderLayout())
	frame.add(panel,BorderLayout.SOUTH)
	button = JButton('check',actionPerformed=self.cbEvents)
	panel.add(button,BorderLayout.SOUTH)
	self.cbStatusLabel =JLabel('select one and click button')
	panel.add(self.cbStatusLabel,BorderLayout.CENTER)

	# now that the panels have been added to the frame show our creation
	frame.pack()
	frame.setVisible(True)

if __name__ == '__main__':
  #start things off.
  CheckBoxExample()
}}}

=== JList ===

 Also see http://www.jython.org/applets/list.html

{{{#!python
"""
Swing JList example in Jython.

Creates a simple list of cities and then updates a JLabel based on the
the city selected.

Greg Moore
Sept 2007
"""

# Using import * is bad form but since this is just a example I'll take the
# easy way out instead of specifing each package.
from javax.swing import *
from java.awt import *

class JListExample:

  def listSelect(self,event):
  	# Process the events from the list box and update the label
    selected = self.list.selectedIndex
    if selected >= 0:
      cityName = self.data[selected]
      self.label.text = cityName

  def __init__(self):

	# These lines setup the basic frame, size and layout
	# the setDefaultCloseOperation is required to completely exit the app
	# when you click the close button
    frame = JFrame("Jython JList Example")
    frame.setSize(200, 225)
    frame.setLayout(BorderLayout())
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)

    # set up the list and the contents of the list
    # the python typle get converted to a Java vector
    self.data = ('Portland','San Francisco','Madrid','Venice','Starnberg','New York','Paris','London')
    self.list = JList(self.data)
    spane = JScrollPane()
    spane.setPreferredSize(Dimension(100,125))
    spane.getViewport().setView((self.list))

	# a panel is a bit over kill but this is a demo. :)
    panel = JPanel()
    panel.add(spane)
    frame.add(panel,BorderLayout.CENTER)

	# create the button, and city label and the show our work
	# with Jython only one line is needed create a button and attach an
	# event handler.
    btn = JButton('Select',actionPerformed=self.listSelect)
    frame.add(btn,BorderLayout.SOUTH)
    self.label = JLabel(' Select City and click select')
    frame.add(self.label,BorderLayout.NORTH)
    frame.pack()
    frame.setVisible(True)


if __name__ == '__main__':
	#start things off.
	JListExample()

}}}

=== JComboBox ===
'' under construction''

Here are a couple of combo box examples. one requires a button click and the other is more dynamic ComboboxExample. 
{{{#!python
"""
Swing JComboBox example in Jython.

Creates a simple comboBox of cities and then updates a JLabel based on the
the city selected after button click.

Greg Moore
Sept 2007

"""

from javax.swing import *
from java.awt import *

class JComboBoxExample:

  def cbSelect(self,event):
    selected = self.cb.selectedIndex
    if selected >= 0:
      data = self.data[selected]
      self.label.text = data + " selected"

  def __init__(self):
    frame = JFrame("Jython JComboBox Example")
    frame.setSize(200, 250)
    frame.setLayout(BorderLayout())

    self.data = ('Portland','San Francisco','Madrid','Venice','Starnberg','New York','Paris','London')
    self.cb = JComboBox(self.data)

    pnl = JPanel()
    pnl.add(self.cb)

    frame.add(pnl,BorderLayout.NORTH)

    btn = JButton('click me',actionPerformed=self.cbSelect)
    frame.add(btn,BorderLayout.SOUTH)
    self.label = JLabel('Select a city then click button')
    frame.add(self.label,BorderLayout.CENTER)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setVisible(True)

if __name__ == '__main__':
	JComboBoxExample()

}}}

=== JTree ===

This example is a bit long so here is the JtreeExample

=== JTable ===

I think this is the most amazing example. This creates a small table that has editable cells, cursor movement and resizeable. The is at least 75% shorter then a comparable java version. Time is money, and here is proof the jython can save you money and make you more productive.


{{{#!python
"""

Swing JTable example in Jython.

Creates a simple table.

Greg Moore
Sept 2007


"""

from javax.swing import *
from java.awt import *
from javax.swing.table import DefaultTableModel

class Example:

  def __init__(self):
    frame = JFrame("Jython JTable Example")
    frame.setSize(400, 150)
    frame.setLayout(BorderLayout())

    self.tableData = [
      ['numbers', '67890' ,'This'],
      ['mo numbers', '2598790', 'is'],
      ['got Math', '2598774', 'a'],
      ['got Numbers', '1234567', 'Column'],
      ['got pi','3.1415926', 'Apple'],
       ]
    colNames = ('Col Labels','Go','Here')
    dataModel = DefaultTableModel(self.tableData, colNames)
    self.table = JTable(dataModel)

    scrollPane = JScrollPane()
    scrollPane.setPreferredSize(Dimension(300,100))
    scrollPane.getViewport().setView((self.table))

    panel = JPanel()
    panel.add(scrollPane)

    frame.add(panel, BorderLayout.CENTER)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setVisible(True)

if __name__ == '__main__':
	Example()

}}}

=== JTabbedPane ===

This create a simple JTabbed''''''Pane example. Here is another TabbedExample.

{{{#!python
"""

Swing JTabbedPane example in Jython.

Greg Moore
Sept 2007

"""

from javax.swing import *
from java.awt import *

class Example:

  def __init__(self):
    frame = JFrame("Jython JTabbedPane Example")
    frame.setSize(400, 300)
    frame.setLayout(BorderLayout())

    tabPane = JTabbedPane(JTabbedPane.TOP)

    label = JLabel("<html><br>This is a tab1</html>")
    panel1 = JPanel()
    panel1.add(label)
    tabPane.addTab("tab1", panel1)

    label2 = JLabel("This is a tab2")

    panel2 = JPanel()
    panel2.add(label2)
    tabPane.addTab("tab2", panel2)

    frame.add(tabPane)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setVisible(True)

if __name__ == '__main__':
	Example()
}}}

=== JSplitPane ===

This just creates a simple split pane. nothing fancy. :)

{{{#!python
"""
Swing JSplitPane example in Jython.

Greg Moore
Sept 2007

"""

from javax.swing import *
from java.awt import *
class Example:

  def __init__(self):
    frame = JFrame("Jython JTable Example")
    frame.setSize(400, 300)
    frame.setLayout(BorderLayout())

    splitPane = JSplitPane(JSplitPane.HORIZONTAL_SPLIT);

    label1 = JLabel("This is a panel1")
    panel1 = JPanel()
    panel1.add(label1)
    splitPane.setLeftComponent(panel1);

    label2 = JLabel("This is a panel2")

    panel2 = JPanel()
    panel2.add(label2)
    splitPane.setRightComponent(panel2);
    splitPane.setDividerLocation(150);

    frame.add(splitPane)
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
    frame.setVisible(True)

if __name__ == '__main__':
    Example()

}}}

=== JDesktopPane and JInternalFrame Demo ===
{{{#!python
from javax.swing import JFrame, JDesktopPane, JInternalFrame, JMenuBar, JMenu, JMenuItem, JScrollPane

class DesktopPaneAndInternalFrameDemo(JFrame):
    """

    A demonstration of JDesktopPane() and JInternalFrame()
    By: astigmatik, Sept 2007

    """
    def __init__(self):
        """
        The JFrame.__init__ lines below don't have to be written in multiple lines.
        This is just for readability.
        """
        JFrame.__init__(self,
                        'JDesktopPane and JInternalFrame Demo',
                        size=(500, 500),
                        defaultCloseOperation=JFrame.EXIT_ON_CLOSE)

        self.internalFrameCounter = 0
        self.createDesktop()
        self.createMenus()

    def createDesktop(self):
        self.desktop = JDesktopPane()
        """
        Normally, it's not allowed to do a "self.object = value" inside the class
        if the self.object has not been instantiated. However, in this case, since we are
        calling self.createDesktopPane() on __init__(), then it is ok.
        """

        self.contentPane.add(JScrollPane(self.desktop)) # This is the same as self.getContentPane().add(...)

    def createMenus(self):

        menu = JMenu('File')
        menu.add(JMenuItem('Create new JInternalFrame', actionPerformed=self.createInternalFrame))

        menubar = JMenuBar()
        menubar.add(menu)

        self.setJMenuBar(menubar)

    def createInternalFrame(self, event):
        """
        event has to be supplied whenever there is an event generated, viz. from a menu being clicked,
        mouse button being clicked, or keypresses, etc.
        """
        self.internalFrameCounter += 1

        iframeName = 'JInternalFrame %s' % self.internalFrameCounter
        iframe     = JInternalFrame(iframeName, 1, 1, 1, 1, size=(400, 400), visible=1)
        """
        The 1's refer to boolean resizable, closable, maximizable, and iconifiable.
        Jython's True and False are 1 and 0 respectively. So all the 1's above can be replaced with True.
        """

        self.desktop.add(iframe)
        iframe.setSelected(1)
        iframe.moveToFront()


if __name__ == '__main__':
    demo = DesktopPaneAndInternalFrameDemo()
    demo.setLocation(30, 30)
    demo.show()
}}}

=== Decorator to add a function to SwingUtilities.invokeLater donated by Alex Grönholm ===
{{{#!python
from java.lang import Runnable
from javax.swing import SwingUtilities
 
class RunnableWrapper(Runnable):
    def __init__(self, func, *args, **kwargs):
        self.func = func
        self.args = args
        self.kwargs = kwargs
 
    def run(self):
        self.func(*self.args, **self.kwargs)
 
def runswing(func):
    """Schedules the given function for execution in the Event Dispatch Thread."""
    def wrapper(*args, **kwargs):
        SwingUtilities.invokeLater(RunnableWrapper(func, *args, **kwargs))
    return wrapper
}}}