Swing Examples in Jython

DocumentationAndEducation


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 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.

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

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

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

   1 from javax.swing import JFrame
   2 f = JFrame('Hello, World!')
   3 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
   4 f.setSize(300, 300)
   5 f.setLocationRelativeTo(None)
   6 f.setVisible(True)

And yet another way of doing it is shown below:

   1 from javax.swing import JFrame
   2 f = JFrame('Hello, World!')
   3 f.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
   4 f.size = (300, 300)
   5 f.locationRelativeTo = None
   6 f.visible = True

JButton and Button events

Just a simple example.

   1 """
   2 A simple example that shows button event handling
   3 
   4 Greg Moore
   5 Sept 2007
   6 """
   7 
   8 from javax.swing import *
   9 from java.awt import BorderLayout
  10 
  11 class Example:
  12   def setText(self,event):
  13       self.label.text = 'Button clicked.'
  14 
  15   def __init__(self):
  16     frame = JFrame("Jython Example JButton")
  17     frame.setSize(100, 100)
  18     frame.setLayout(BorderLayout())
  19     self.label = JLabel('Hello from Jython')
  20     frame.add(self.label, BorderLayout.NORTH)
  21     button = JButton('Click Me',actionPerformed=self.setText)
  22     frame.add(button, BorderLayout.SOUTH)
  23     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  24     frame.setVisible(True)
  25 
  26 if __name__ == '__main__':
  27         Example()

JTextField

   1 """
   2 Swing JTextField example in Jython.
   3 
   4 Creates 2 text fields and clicking the button copies text in one textfield
   5 to the other. 
   6 
   7 Greg Moore
   8 Sept 2007
   9 """
  10 
  11 from javax.swing import *
  12 from java.lang import *
  13 
  14 class Example:
  15 
  16   def copyText(self,event):
  17       self.textfield2.text = self.textfield1.text
  18 
  19   def __init__(self):
  20         # These lines setup the basic frame, size.
  21         # the setDefaultCloseOperation is required to completely exit the app
  22         # when you click the close button
  23     frame = JFrame("Jython JText Field Example")
  24     frame.setSize(200, 150)
  25     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  26 
  27     # Create Panel and add swing components and show it.
  28     pnl = JPanel()
  29     frame.add(pnl)
  30     self.textfield1 = JTextField('Type something here',15)
  31     pnl.add(self.textfield1)
  32     self.textfield2 = JTextField('and click Copy', 15)
  33     pnl.add(self.textfield2)
  34     copyButton = JButton('Copy',actionPerformed=self.copyText)
  35     pnl.add(copyButton)
  36     frame.pack()
  37     frame.setVisible(True)
  38 
  39 if __name__ == '__main__':
  40   #start things off.
  41   Example()

JRadioButton

   1 """
   2 Swing JRadioButton example in Jython.
   3 
   4 Creates radio buttons and event handler
   5 
   6 Greg Moore
   7 Sept 2007
   8 """
   9 
  10 # Using import * is bad form but since this is just a example I'll take the
  11 # easy way out instead of specifing each package.
  12 from javax.swing import *
  13 from java.awt import *
  14 
  15 
  16 class RadioButtonExample:
  17   def radioBtnbCheck(self,event):
  18     # Process the events and update the label
  19     statusText = ""
  20     if self.radioBtn1.isSelected():
  21       statusText = "Radio Button 1 is selected "
  22     if self.radioBtn2.isSelected():
  23       statusText = statusText + "Radio Button 2 is selected "
  24     self.rbStatusLabel.text = statusText
  25 
  26   def __init__(self):
  27         # These lines setup the basic frame, size and layout
  28         # the setDefaultCloseOperation is required to completely exit the app
  29         # when you click the close button
  30     frame = JFrame("Jython Example JRadioButton")
  31     frame.setSize(400, 150)
  32     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  33     frame.setLayout(BorderLayout())
  34 
  35     # create 2 panels the top one containing radio buttons and the bottom one
  36     # has the label and button. add them to the frame and show it.
  37     rbPanel = JPanel()
  38     frame.add(rbPanel,BorderLayout.NORTH)
  39     self.radioBtn1 = JRadioButton('Radio Button 1')
  40     self.radioBtn2 = JRadioButton('Radio Button 2')
  41     rbPanel.add(self.radioBtn1)
  42     rbPanel.add(self.radioBtn2)
  43     rbBtnGroup = ButtonGroup()
  44     rbBtnGroup.add(self.radioBtn1)
  45     rbBtnGroup.add(self.radioBtn2)
  46 
  47     panel = JPanel()
  48     panel.setLayout(BorderLayout())
  49     frame.add(panel,BorderLayout.SOUTH)
  50     button = JButton('Check',actionPerformed=self.radioBtnbCheck)
  51     panel.add(button,BorderLayout.WEST)
  52     self.rbStatusLabel =JLabel()
  53     panel.add(self.rbStatusLabel,BorderLayout.EAST)
  54     frame.pack()
  55     frame.setVisible(True)
  56 
  57 if __name__ == '__main__':
  58   #start things off.
  59   RadioButtonExample()

JCheckBox

   1 """
   2 Swing JCheckBox example in Jython.
   3 
   4 Creates a couple checkboxes and and event handler
   5 
   6 Greg Moore
   7 Sept 2007
   8 """
   9 
  10 # Using import * is bad form but since this is just a example I'll take the
  11 # easy way out instead of specifing each package.
  12 from javax.swing import *
  13 from java.awt import *
  14 
  15 class CheckBoxExample:
  16 
  17   def cbEvents(self,event):
  18         # Process the events and update the label
  19     cbStatusMsg=""
  20     if self.chkbox1.isSelected():
  21       cbStatusMsg = "checkbox1 is selected "
  22     if self.chkbox2.isSelected():
  23       cbStatusMsg = cbStatusMsg + "checkbox2 is selected"
  24     self.cbStatusLabel.text = cbStatusMsg
  25 
  26   def __init__(self):
  27         # These lines setup the basic frame, size and layout
  28         # the setDefaultCloseOperation is required to completely exit the app
  29         # when you click the close button
  30         frame = JFrame("Jython JCheckBox Example")
  31         frame.setLayout(BorderLayout())
  32         frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  33         
  34         # this could be done with only one JPanel or use different layout
  35         # create a panel for the checkboxes
  36         cbPanel = JPanel()
  37         frame.add(cbPanel,BorderLayout.NORTH)
  38         self.chkbox1 = JCheckBox('checkbox 1')
  39         self.chkbox2 = JCheckBox('checkbox 2')
  40         cbPanel.add(self.chkbox1)
  41         cbPanel.add(self.chkbox2)
  42 
  43         # create a second panel with the button and label
  44         panel = JPanel()
  45         panel.setLayout(BorderLayout())
  46         frame.add(panel,BorderLayout.SOUTH)
  47         button = JButton('check',actionPerformed=self.cbEvents)
  48         panel.add(button,BorderLayout.SOUTH)
  49         self.cbStatusLabel =JLabel('select one and click button')
  50         panel.add(self.cbStatusLabel,BorderLayout.CENTER)
  51 
  52         # now that the panels have been added to the frame show our creation
  53         frame.pack()
  54         frame.setVisible(True)
  55 
  56 if __name__ == '__main__':
  57   #start things off.
  58   CheckBoxExample()

JList

   1 """
   2 Swing JList example in Jython.
   3 
   4 Creates a simple list of cities and then updates a JLabel based on the
   5 the city selected.
   6 
   7 Greg Moore
   8 Sept 2007
   9 """
  10 
  11 # Using import * is bad form but since this is just a example I'll take the
  12 # easy way out instead of specifing each package.
  13 from javax.swing import *
  14 from java.awt import *
  15 
  16 class JListExample:
  17 
  18   def listSelect(self,event):
  19         # Process the events from the list box and update the label
  20     selected = self.list.selectedIndex
  21     if selected >= 0:
  22       cityName = self.data[selected]
  23       self.label.text = cityName
  24 
  25   def __init__(self):
  26 
  27         # These lines setup the basic frame, size and layout
  28         # the setDefaultCloseOperation is required to completely exit the app
  29         # when you click the close button
  30     frame = JFrame("Jython JList Example")
  31     frame.setSize(200, 225)
  32     frame.setLayout(BorderLayout())
  33     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  34 
  35     # set up the list and the contents of the list
  36     # the python typle get converted to a Java vector
  37     self.data = ('Portland','San Francisco','Madrid','Venice','Starnberg','New York','Paris','London')
  38     self.list = JList(self.data)
  39     spane = JScrollPane()
  40     spane.setPreferredSize(Dimension(100,125))
  41     spane.getViewport().setView((self.list))
  42 
  43         # a panel is a bit over kill but this is a demo. :)
  44     panel = JPanel()
  45     panel.add(spane)
  46     frame.add(panel,BorderLayout.CENTER)
  47 
  48         # create the button, and city label and the show our work
  49         # with Jython only one line is needed create a button and attach an
  50         # event handler.
  51     btn = JButton('Select',actionPerformed=self.listSelect)
  52     frame.add(btn,BorderLayout.SOUTH)
  53     self.label = JLabel(' Select City and click select')
  54     frame.add(self.label,BorderLayout.NORTH)
  55     frame.pack()
  56     frame.setVisible(True)
  57 
  58 
  59 if __name__ == '__main__':
  60         #start things off.
  61         JListExample()

JComboBox

under construction

Here are a couple of combo box examples. one requires a button click and the other is more dynamic ComboboxExample.

   1 """
   2 Swing JComboBox example in Jython.
   3 
   4 Creates a simple comboBox of cities and then updates a JLabel based on the
   5 the city selected after button click.
   6 
   7 Greg Moore
   8 Sept 2007
   9 
  10 """
  11 
  12 from javax.swing import *
  13 from java.awt import *
  14 
  15 class JComboBoxExample:
  16 
  17   def cbSelect(self,event):
  18     selected = self.cb.selectedIndex
  19     if selected >= 0:
  20       data = self.data[selected]
  21       self.label.text = data + " selected"
  22 
  23   def __init__(self):
  24     frame = JFrame("Jython JComboBox Example")
  25     frame.setSize(200, 250)
  26     frame.setLayout(BorderLayout())
  27 
  28     self.data = ('Portland','San Francisco','Madrid','Venice','Starnberg','New York','Paris','London')
  29     self.cb = JComboBox(self.data)
  30 
  31     pnl = JPanel()
  32     pnl.add(self.cb)
  33 
  34     frame.add(pnl,BorderLayout.NORTH)
  35 
  36     btn = JButton('click me',actionPerformed=self.cbSelect)
  37     frame.add(btn,BorderLayout.SOUTH)
  38     self.label = JLabel('Select a city then click button')
  39     frame.add(self.label,BorderLayout.CENTER)
  40     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  41     frame.setVisible(True)
  42 
  43 if __name__ == '__main__':
  44         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.

   1 """
   2 
   3 Swing JTable example in Jython.
   4 
   5 Creates a simple table.
   6 
   7 Greg Moore
   8 Sept 2007
   9 
  10 
  11 """
  12 
  13 from javax.swing import *
  14 from java.awt import *
  15 from javax.swing.table import DefaultTableModel
  16 
  17 class Example:
  18 
  19   def __init__(self):
  20     frame = JFrame("Jython JTable Example")
  21     frame.setSize(400, 150)
  22     frame.setLayout(BorderLayout())
  23 
  24     self.tableData = [
  25       ['numbers', '67890' ,'This'],
  26       ['mo numbers', '2598790', 'is'],
  27       ['got Math', '2598774', 'a'],
  28       ['got Numbers', '1234567', 'Column'],
  29       ['got pi','3.1415926', 'Apple'],
  30        ]
  31     colNames = ('Col Labels','Go','Here')
  32     dataModel = DefaultTableModel(self.tableData, colNames)
  33     self.table = JTable(dataModel)
  34 
  35     scrollPane = JScrollPane()
  36     scrollPane.setPreferredSize(Dimension(300,100))
  37     scrollPane.getViewport().setView((self.table))
  38 
  39     panel = JPanel()
  40     panel.add(scrollPane)
  41 
  42     frame.add(panel, BorderLayout.CENTER)
  43     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  44     frame.setVisible(True)
  45 
  46 if __name__ == '__main__':
  47         Example()

JTabbedPane

This create a simple JTabbedPane example. Here is another TabbedExample.

   1 """
   2 
   3 Swing JTabbedPane example in Jython.
   4 
   5 Greg Moore
   6 Sept 2007
   7 
   8 """
   9 
  10 from javax.swing import *
  11 from java.awt import *
  12 
  13 class Example:
  14 
  15   def __init__(self):
  16     frame = JFrame("Jython JTabbedPane Example")
  17     frame.setSize(400, 300)
  18     frame.setLayout(BorderLayout())
  19 
  20     tabPane = JTabbedPane(JTabbedPane.TOP)
  21 
  22     label = JLabel("<html><br>This is a tab1</html>")
  23     panel1 = JPanel()
  24     panel1.add(label)
  25     tabPane.addTab("tab1", panel1)
  26 
  27     label2 = JLabel("This is a tab2")
  28 
  29     panel2 = JPanel()
  30     panel2.add(label2)
  31     tabPane.addTab("tab2", panel2)
  32 
  33     frame.add(tabPane)
  34     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  35     frame.setVisible(True)
  36 
  37 if __name__ == '__main__':
  38         Example()

JSplitPane

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

   1 """
   2 Swing JSplitPane example in Jython.
   3 
   4 Greg Moore
   5 Sept 2007
   6 
   7 """
   8 
   9 from javax.swing import *
  10 from java.awt import *
  11 class Example:
  12 
  13   def __init__(self):
  14     frame = JFrame("Jython JTable Example")
  15     frame.setSize(400, 300)
  16     frame.setLayout(BorderLayout())
  17 
  18     splitPane = JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
  19 
  20     label1 = JLabel("This is a panel1")
  21     panel1 = JPanel()
  22     panel1.add(label1)
  23     splitPane.setLeftComponent(panel1);
  24 
  25     label2 = JLabel("This is a panel2")
  26 
  27     panel2 = JPanel()
  28     panel2.add(label2)
  29     splitPane.setRightComponent(panel2);
  30     splitPane.setDividerLocation(150);
  31 
  32     frame.add(splitPane)
  33     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
  34     frame.setVisible(True)
  35 
  36 if __name__ == '__main__':
  37     Example()

JDesktopPane and JInternalFrame Demo

   1 from javax.swing import JFrame, JDesktopPane, JInternalFrame, JMenuBar, JMenu, JMenuItem, JScrollPane
   2 
   3 class DesktopPaneAndInternalFrameDemo(JFrame):
   4     """
   5 
   6     A demonstration of JDesktopPane() and JInternalFrame()
   7     By: astigmatik, Sept 2007
   8 
   9     """
  10     def __init__(self):
  11         """
  12         The JFrame.__init__ lines below don't have to be written in multiple lines.
  13         This is just for readability.
  14         """
  15         JFrame.__init__(self,
  16                         'JDesktopPane and JInternalFrame Demo',
  17                         size=(500, 500),
  18                         defaultCloseOperation=JFrame.EXIT_ON_CLOSE)
  19 
  20         self.internalFrameCounter = 0
  21         self.createDesktop()
  22         self.createMenus()
  23 
  24     def createDesktop(self):
  25         self.desktop = JDesktopPane()
  26         """
  27         Normally, it's not allowed to do a "self.object = value" inside the class
  28         if the self.object has not been instantiated. However, in this case, since we are
  29         calling self.createDesktopPane() on __init__(), then it is ok.
  30         """
  31 
  32         self.contentPane.add(JScrollPane(self.desktop)) # This is the same as self.getContentPane().add(...)
  33 
  34     def createMenus(self):
  35 
  36         menu = JMenu('File')
  37         menu.add(JMenuItem('Create new JInternalFrame', actionPerformed=self.createInternalFrame))
  38 
  39         menubar = JMenuBar()
  40         menubar.add(menu)
  41 
  42         self.setJMenuBar(menubar)
  43 
  44     def createInternalFrame(self, event):
  45         """
  46         event has to be supplied whenever there is an event generated, viz. from a menu being clicked,
  47         mouse button being clicked, or keypresses, etc.
  48         """
  49         self.internalFrameCounter += 1
  50 
  51         iframeName = 'JInternalFrame %s' % self.internalFrameCounter
  52         iframe     = JInternalFrame(iframeName, 1, 1, 1, 1, size=(400, 400), visible=1)
  53         """
  54         The 1's refer to boolean resizable, closable, maximizable, and iconifiable.
  55         Jython's True and False are 1 and 0 respectively. So all the 1's above can be replaced with True.
  56         """
  57 
  58         self.desktop.add(iframe)
  59         iframe.setSelected(1)
  60         iframe.moveToFront()
  61 
  62 
  63 if __name__ == '__main__':
  64     demo = DesktopPaneAndInternalFrameDemo()
  65     demo.setLocation(30, 30)
  66     demo.show()

Decorator to add a function to SwingUtilities.invokeLater donated by Alex Gr├Ânholm

   1 from java.lang import Runnable
   2 from javax.swing import SwingUtilities
   3  
   4 class RunnableWrapper(Runnable):
   5     def __init__(self, func, *args, **kwargs):
   6         self.func = func
   7         self.args = args
   8         self.kwargs = kwargs
   9  
  10     def run(self):
  11         self.func(*self.args, **self.kwargs)
  12  
  13 def runswing(func):
  14     """Schedules the given function for execution in the Event Dispatch Thread."""
  15     def wrapper(*args, **kwargs):
  16         SwingUtilities.invokeLater(RunnableWrapper(func, *args, **kwargs))
  17     return wrapper

ADB SwingExamples (last edited 2011-08-07 01:33:32 by h86)