JAVA Swing Tutorial - JFrame tutorial

JFrame

Java Swing Tutorial Explaining the JFrame class. The components added to the frame are referred to as its contents; these are managed by the contentPane. To add a component to a JFrame, we must use its contentPane instead.JFrame is a Window with border, title and buttons. When JFrame is set visible, an event dispatching thread is started. JFrame objects store several objects including a Container object known as the content pane. To add a component to a JFrame, add it to the content pane.

JFrame Features

It’s a window with title, border, (optional) menu bar and user-specified components.
It can be moved, resized, iconified.
It is not a subclass of JComponent.
Delegates responsibility of managing user-specified components to a content pane, an instance of JPanel.

Centering JFrame’s

By default, a Jframe is displayed in the upper-left corner of the screen. To display a frame
at a specified location, you can use the setLocation(x, y) method in the JFrame class. This
method places the upper-left corner of a frame at location (x, y).

The Swing API keeps improving with abstractions such as the setDefaultCloseOperation method
for the JFrame

Crating a JFrame Window

Step 1: Construct an object of the JFrame class.

Step 2: Set the size of the Jframe.

Step 3: Set the title of the Jframe to appear in the title bar (title bar will be blank if no title is set).

Step 4: Set the default close operation. When the user clicks the close button, the program stops running.

Step 5: Make the Jframe visible.

How to position JFrame on Screen?

frame.setLocationRelativeTo( null );

JFrame Source Code

import java.awt.*; import java.awt.event.*; import javax.swing.*; public class JFrameDemo {         public static void main(String s[]) {                JFrame frame = new JFrame("JFrame Source Demo");                // Add a window listner for close button                frame.addWindowListener(new WindowAdapter() {                        public void windowClosing(WindowEvent e) {                                System.exit(0);                        }                });                // This is an empty content area in the frame                JLabel jlbempty = new JLabel("");                jlbempty.setPreferredSize(new Dimension(175, 100));                frame.getContentPane().add(jlbempty, BorderLayout.CENTER);                frame.pack();                frame.setVisible(true);         } }

Output

Swing Replacements for AWT Components

Use the following table as a guide for choosing a Swing replacement for each AWT component used in your program.

AWT Component	Closest Swing Equivalent	Notes
java.applet.Applet	JApplet	AWT applets and Swing applets differ in several ways. See Converting Applets.
Button	JButton	A Swing button can include an image and/or text.
Canvas	JPanel, JLabel, or another appropriate Swing component	Your choice depends on what the program uses the canvas for. See Converting Canvases for a discussion of your conversion options.
Checkbox	JCheckBox or JRadioButton	Note the `B' is capitalized in the Swing class name but not in the AWT class name.
CheckboxMenuItem	JCheckBoxMenuItem	Note the `B' is capitalized in the Swing class name but not in the AWT class name. Also, note that Swing menu components are true components.
Choice	JComboBox	Replace a Choice with an uneditable (the default) JComboBox. You might have to re-write code that handles item events. Refer to Converting Choices.
Dialog	JDialog or JOptionPane	AWT-based programs add components directly to a dialog and directly set its layout manager. In contrast, Swing-based programs add components to and set the layout manager on a JDialog'scontent pane.
FileDialog	JFileChooser	FileDialog is a dialog, while JFileChooser is a component that you can place in any top-level container. For convenience, JFileChooser provides methods that make it easy to display a file chooser in a dialog.
Frame	JFrame	AWT-based programs add components directly to a frame and directly set its layout manager. In contrast, Swing-based programs add components to and set the layout manager on a JFrame'scontent pane.
Label	JLabel	A Swing label can include an image and/or text. To support accessibility, use setLabelFor to associate each label with the component it describes (if any).
List	JList	AWT lists and Swing lists differ in many ways. See Converting Lists for information and examples. If you'd like your list to display multiple columns of information, consider upgrading to a table. If the list contains hierarchical informaiton, consider using a tree.
Menu	JMenu	Swing menu components are true components.
MenuBar	JMenuBar	Swing menu components are true components.
MenuItem	JMenuItem	Swing menu components are true components.
Panel	JPanel	You can easily add borders to Swing panels.
PopupMenu	JPopupMenu	Swing menu components are true components.
Scrollbar	JScrollPane or JSlider or JProgressBar	Although Swing has a JScrollBar class, you don't usually use it directly.
ScrollPane	JScrollPane	You can add custom decorations, including row and column headers, to Swing scroll panes.
TextArea	JTextArea	Typically requires some re-coding to convert. See Converting Text Components for information and examples.
TextField	JTextField	For simple uses, JTextField is source-compatible with TextField. If you use text listeners you need to modify your code to use a custom document or document listener instead. If you need a password field, use JPasswordField instead. See Converting Text Components for information about non-trivial conversions and examples.
	JWindow or JToolTip	You might be able to substitute a non-window component, such as a JLabel, and use a layered pane.