javax.swing

Class JProgressBar

java.lang.Object

java.awt.Component

java.awt.Container

javax.swing.JComponent

javax.swing.JProgressBar

All Implemented Interfaces:

ImageObserver, MenuContainer, Serializable, Accessible, SwingConstants

public class JProgressBar
extends JComponent
implements SwingConstants, Accessible

A component that visually displays the progress of some task. As the task progresses towards completion, the progress bar displays the task's percentage of completion. This percentage is typically represented visually by a rectangle which starts out empty and gradually becomes filled in as the task progresses. In addition, the progress bar can display a textual representation of this percentage.

JProgressBar uses a BoundedRangeModel as its data model, with the value property representing the "current" state of the task, and the minimum and maximum properties representing the beginning and end points, respectively.

To indicate that a task of unknown length is executing, you can put a progress bar into indeterminate mode. While the bar is in indeterminate mode, it animates constantly to show that work is occurring. As soon as you can determine the task's length and amount of progress, you should update the progress bar's value and switch it back to determinate mode.

Here is an example of creating a progress bar, where task is an object (representing some piece of work) which returns information about the progress of the task:

progressBar = new JProgressBar(0, task.getLengthOfTask());
progressBar.setValue(0);
progressBar.setStringPainted(true);

Here is an example of querying the current state of the task, and using the returned value to update the progress bar:

progressBar.setValue(task.getCurrent());

Here is an example of putting a progress bar into indeterminate mode, and then switching back to determinate mode once the length of the task is known:

progressBar = new JProgressBar();
...//when the task of (initially) unknown length begins:
progressBar.setIndeterminate(true);
...//do some work; get length of task...
progressBar.setMaximum(newLength);
progressBar.setValue(newValue);
progressBar.setIndeterminate(false);

For complete examples and further documentation see How to Monitor Progress, a section in The Java Tutorial.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

See Also:

BasicProgressBarUI, BoundedRangeModel, SwingWorker

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	JProgressBar.AccessibleJProgressBar	This class implements accessibility support for the JProgressBar class.

Nested classes/interfaces inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields

Modifier and Type	Field	Description
protected ChangeEvent	changeEvent	Only one ChangeEvent is needed per instance since the event's only interesting property is the immutable source, which is the progress bar.
protected ChangeListener	changeListener	Listens for change events sent by the progress bar's model, redispatching them to change-event listeners registered upon this progress bar.
protected BoundedRangeModel	model	The object that holds the data for the progress bar.
protected int	orientation	Whether the progress bar is horizontal or vertical.
protected boolean	paintBorder	Whether to display a border around the progress bar.
protected boolean	paintString	Whether to display a string of text on the progress bar.
protected String	progressString	An optional string that can be displayed on the progress bar.

Fields inherited from class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

Constructors

Constructor	Description
JProgressBar()	Creates a horizontal progress bar that displays a border but no progress string.
JProgressBar(BoundedRangeModel newModel)	Creates a horizontal progress bar that uses the specified model to hold the progress bar's data.
JProgressBar(int orient)	Creates a progress bar with the specified orientation, which can be either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.
JProgressBar(int min, int max)	Creates a horizontal progress bar with the specified minimum and maximum.
JProgressBar(int orient, int min, int max)	Creates a progress bar using the specified orientation, minimum, and maximum.

Method Summary

Modifier and Type	Method	Description
void	addChangeListener(ChangeListener l)	Adds the specified ChangeListener to the progress bar.
protected ChangeListener	createChangeListener()	Subclasses that want to handle change events from the model differently can override this to return an instance of a custom ChangeListener implementation.
protected void	fireStateChanged()	Send a ChangeEvent, whose source is this JProgressBar, to all ChangeListeners that have registered interest in ChangeEvents.
AccessibleContext	getAccessibleContext()	Gets the AccessibleContext associated with this JProgressBar.
ChangeListener[]