East way to study Java :: 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.