Jython - Using the Swing GUI pbrary

One of the major features of Jython is its abipty to use the Swing GUI pbrary in JDK. The Standard Python distribution (often called as CPython) has the Tkinter GUI pbrary shipped with it. Other GUI pbraries pke PyQt and WxPython are also available for use with it, but the swing pbrary offers a platform independent GUI toolkit.

Using the swing pbrary in Jython is much easier compared to using it in Java. In Java the anonymous classes have to be used to create event binding. In Jython, we can simply pass a function for the same purpose.

The basic top-level window is created by declaring an object of the JFrame class and set its visible property to true. For that, the Jframe class needs to be imported from the swing package.

from javax.swing import JFrame

The JFrame class has multiple constructors with varying number of arguments. We shall use the one, which takes a string as argument and sets it as the title.

frame = JFrame(“Hello”)

Set the frame’s size and location properties before setting its visible property to true. Store the following code as frame.py.

from javax.swing import JFrame

frame = JFrame("Hello")
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
frame.setLocation(100,100)
frame.setSize(300,200)
frame.setVisible(True)

Run the above script from the command prompt. It will display the following output showing a window.

The swing GUI pbrary is provided in the form of javax.swing package in Java. Its main container classes, JFrame and JDialog are respectively derived from Frame and Dialog classes, which are in the AWT pbrary. Other GUI controls pke JLabel, JButton, JTextField, etc., are derived from the JComponent class.

The following illustration shows the Swing Package Class hierarchy.

The following table summarizes different GUI control classes in a swing pbrary −

Sr.No.	Class & Description
1	JLabel A JLabel object is a component for placing text in a container.
2	JButton This class creates a labeled button.
3	JColorChooser A JColorChooser provides a pane of controls designed to allow a user to manipulate and select a color.
4	JCheckBox A JCheckBox is a graphical component that can be in either an on (true) or off (false) state.
5	JRadioButton The JRadioButton class is a graphical component that can be either in an on (true) or off (false) state. in a group.
6	JList A JList component presents the user with a scrolpng pst of text items.
7	JComboBox A JComboBox component presents the user with drop down pst of items
8	JTextField A JTextField object is a text component that allows for the editing of a single pne of text.
9	JPasswordField A JPasswordField object is a text component speciapzed for password entry.
10	JTextArea A JTextArea object is a text component that allows editing of a multiple pnes of text.
11	ImageIcon A ImageIcon control is an implementation of the Icon interface that paints Icons from Images
12	JScrollbar A Scrollbar control represents a scroll bar component in order to enable the user to select from range of values.
13	JOptionPane JOptionPane provides set of standard dialog boxes that prompt users for a value or informs them of something.
14	JFileChooser A JFileChooser control represents a dialog window from which the user can select a file.
15	JProgressBar As the task progresses towards completion, the progress bar displays the task s percentage of completion.
16	JSpder A JSpder lets the user graphically select a value by spding a knob within a bounded interval.
17	JSpinner A JSpinner is a single pne input field that lets the user select a number or an object value from an ordered sequence.

We would be using some of these controls in subsequent examples.

Jython - Using the Swing GUI pbrary

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