JSwings - JFrames

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

Java JFrame Hierarchy
javax.swing


Class JFrame

java.lang.Object

java.awt.Component

java.awt.Container

java.awt.Window

java.awt.Frame

javax.swing.JFrame

All Implemented Interfaces:

Accessible, ImageObserver, MenuContainer, RootPaneContainer, Serializable,
WindowConstants

JFrame Constructor

JFrame()

Constructs a new frame that is initially invisible.

JFrame(GraphicsConfiguration gc)

Creates a Frame in the specified GraphicsConfiguration of a screen device and a
blank title.

JFrame(String title)

Creates a new, initially invisible Frame with the specified title.

JFrame(String title, GraphicsConfiguration gc)

Creates a JFrame with the specified title and the specified
GraphicsConfiguration of a screen device.