Java JRootPane

JRootPane is a lightweight container used behind the scenes by JFrame, JDialog, JWindow, JApplet, and JInternalFrame.

Nested Classes

Modifier and Type	Class	Description
protected class	JRootPane.AccessibleJRootPane	This class implements accessibility support for the JRootPane class.
protected class	JRootPane.RootLayout	A custom layout manager that is responsible for the layout of layeredPane, glassPane, and menuBar.

Fields

Modifier and Type	Field	Description
static int	COLOR_CHOOSER_DIALOG	Constant used for the windowDecorationStyle property.
protected JButton	contentPane	The content pane.
protected Container	defaultButton	The button that gets activated when the pane has the focus and a UI-specific action like pressing the Enter key occurs.
protected JMenuBar	menuBar	The menu bar.
protected Component	glassPane	The glass pane that overlays the menu bar and content pane, so it can intercept mouse movements and such.
static int	ERROR_DIALOG	Constant used for the windowDecorationStyle property.

Constructor

Constructor	Description
JRootPane()	Creates a JRootPane, setting up its glassPane, layeredPane, and contentPane.

Useful Methods

Modifier and Type	Method	Description
protected void	addImpl(Component comp, Object constraints, int index)	Overridden to enforce the position of the glass component as the zero child.
void	addNotify()	Notifies this component that it now has a parent component.
protected Container	createContentPane()	It is called by the constructor methods to create the default contentPane.
protected Component	createGlassPane()	It called by the constructor methods to create the default glassPane.
AccessibleContext	getAccessibleContext()	It gets the AccessibleContext associated with this JRootPane.
JButton	getDefaultButton()	It returns the value of the defaultButton property.
void	setContentPane(Container content)	It sets the content pane -- the container that holds the components parented by the root pane.
void	setDefaultButton(JButton defaultButton)	It sets the defaultButton property, which determines the current default button for this JRootPane.
void	setJMenuBar(JMenuBar menu)	It adds or changes the menu bar used in the layered pane.

JRootPane Example

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JRootPane;

public class JRootPaneExample {
	 public static void main(String[] args) {
		    JFrame f = new JFrame();
		    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		    JRootPane root = f.getRootPane();

		    // Create a menu bar
		    JMenuBar bar = new JMenuBar();
		    JMenu menu = new JMenu("File");
		    bar.add(menu);
		    menu.add("Open");
		    menu.add("Close");
		    root.setJMenuBar(bar);

		    // Add a button to the content pane
		    root.getContentPane().add(new JButton("Press Me"));

		    // Display the UI
		    f.pack();
		    f.setVisible(true);
		  }
}

Output