public class

BasicLabelUI

extends LabelUI
implements PropertyChangeListener
java.lang.Object
   ↳ javax.swing.plaf.ComponentUI
     ↳ javax.swing.plaf.LabelUI
       ↳ javax.swing.plaf.basic.BasicLabelUI
Known Direct Subclasses

Class Overview

A Windows L&F implementation of LabelUI. This implementation is completely static, i.e. there's only one UIView implementation that's shared by all JLabel objects.

Summary

Fields
protected static BasicLabelUI labelUI The default BasicLabelUI instance.
Public Constructors
BasicLabelUI()
Public Methods
static ComponentUI createUI(JComponent c)
int getBaseline(JComponent c, int width, int height)
Returns the baseline.
Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
Returns an enum indicating how the baseline of the component changes as the size changes.
Dimension getMaximumSize(JComponent c)
Returns the specified component's maximum size appropriate for the look and feel.
Dimension getMinimumSize(JComponent c)
Returns the specified component's minimum size appropriate for the look and feel.
Dimension getPreferredSize(JComponent c)
Returns the specified component's preferred size appropriate for the look and feel.
void installUI(JComponent c)
Configures the specified component appropriate for the look and feel.
void paint(Graphics g, JComponent c)
Paint the label text in the foreground color, if the label is opaque then paint the entire background with the background color.
void propertyChange(PropertyChangeEvent e)
This method gets called when a bound property is changed.
void uninstallUI(JComponent c)
Reverses configuration which was done on the specified component during installUI.
Protected Methods
void installComponents(JLabel c)
void installDefaults(JLabel c)
void installKeyboardActions(JLabel l)
void installListeners(JLabel c)
String layoutCL(JLabel label, FontMetrics fontMetrics, String text, Icon icon, Rectangle viewR, Rectangle iconR, Rectangle textR)
Forwards the call to SwingUtilities.layoutCompoundLabel().
void paintDisabledText(JLabel l, Graphics g, String s, int textX, int textY)
Paint clippedText at textX, textY with background.lighter() and then shifted down and to the right by one pixel with background.darker().
void paintEnabledText(JLabel l, Graphics g, String s, int textX, int textY)
Paint clippedText at textX, textY with the labels foreground color.
void uninstallComponents(JLabel c)
void uninstallDefaults(JLabel c)
void uninstallKeyboardActions(JLabel c)
void uninstallListeners(JLabel c)
[Expand]
Inherited Methods
From class javax.swing.plaf.ComponentUI
From class java.lang.Object
From interface java.beans.PropertyChangeListener

Fields

protected static BasicLabelUI labelUI

The default BasicLabelUI instance. This field might not be used. To change the default instance use a subclass which overrides the createUI method, and place that class name in defaults table under the key "LabelUI".

Public Constructors

public BasicLabelUI ()

Public Methods

public static ComponentUI createUI (JComponent c)

public int getBaseline (JComponent c, int width, int height)

Returns the baseline.

Parameters
c JComponent baseline is being requested for
width the width to get the baseline for
height the height to get the baseline for
Returns
  • baseline or a value < 0 indicating there is no reasonable baseline
Throws
NullPointerException
IllegalArgumentException
See Also

public Component.BaselineResizeBehavior getBaselineResizeBehavior (JComponent c)

Returns an enum indicating how the baseline of the component changes as the size changes.

Parameters
c JComponent to return baseline resize behavior for
Returns
  • an enum indicating how the baseline changes as the component size changes
Throws
NullPointerException
See Also

public Dimension getMaximumSize (JComponent c)

Returns the specified component's maximum size appropriate for the look and feel. If null is returned, the maximum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes getPreferredSize and returns that value.

Parameters
c the component whose maximum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
Returns
  • getPreferredSize(c)

public Dimension getMinimumSize (JComponent c)

Returns the specified component's minimum size appropriate for the look and feel. If null is returned, the minimum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes getPreferredSize and returns that value.

Parameters
c the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
Returns
  • getPreferredSize(c)

public Dimension getPreferredSize (JComponent c)

Returns the specified component's preferred size appropriate for the look and feel. If null is returned, the preferred size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method returns null.

Parameters
c the component whose preferred size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

public void installUI (JComponent c)

Configures the specified component appropriate for the look and feel. This method is invoked when the ComponentUI instance is being installed as the UI delegate on the specified component. This method should completely configure the component for the look and feel, including the following:

  1. Install any default property values for color, fonts, borders, icons, opacity, etc. on the component. Whenever possible, property values initialized by the client program should not be overridden.
  2. Install a LayoutManager on the component if necessary.
  3. Create/add any required sub-components to the component.
  4. Create/install event listeners on the component.
  5. Create/install a PropertyChangeListener on the component in order to detect and respond to component property changes appropriately.
  6. Install keyboard UI (mnemonics, traversal, etc.) on the component.
  7. Initialize any appropriate instance data.

Parameters
c the component where this UI delegate is being installed

public void paint (Graphics g, JComponent c)

Paint the label text in the foreground color, if the label is opaque then paint the entire background with the background color. The Label text is drawn by paintEnabledText() or paintDisabledText(). The locations of the label parts are computed by layoutCL.

Parameters
g the Graphics context in which to paint
c the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
See Also

public void propertyChange (PropertyChangeEvent e)

This method gets called when a bound property is changed.

Parameters
e A PropertyChangeEvent object describing the event source and the property that has changed.

public void uninstallUI (JComponent c)

Reverses configuration which was done on the specified component during installUI. This method is invoked when this UIComponent instance is being removed as the UI delegate for the specified component. This method should undo the configuration performed in installUI, being careful to leave the JComponent instance in a clean state (no extraneous listeners, look-and-feel-specific property objects, etc.). This should include the following:

  1. Remove any UI-set borders from the component.
  2. Remove any UI-set layout managers on the component.
  3. Remove any UI-added sub-components from the component.
  4. Remove any UI-added event/property listeners from the component.
  5. Remove any UI-installed keyboard UI from the component.
  6. Nullify any allocated instance data objects to allow for GC.

Parameters
c the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

Protected Methods

protected void installComponents (JLabel c)

protected void installDefaults (JLabel c)

protected void installKeyboardActions (JLabel l)

protected void installListeners (JLabel c)

protected String layoutCL (JLabel label, FontMetrics fontMetrics, String text, Icon icon, Rectangle viewR, Rectangle iconR, Rectangle textR)

Forwards the call to SwingUtilities.layoutCompoundLabel(). This method is here so that a subclass could do Label specific layout and to shorten the method name a little.

See Also

protected void paintDisabledText (JLabel l, Graphics g, String s, int textX, int textY)

Paint clippedText at textX, textY with background.lighter() and then shifted down and to the right by one pixel with background.darker().

See Also

protected void paintEnabledText (JLabel l, Graphics g, String s, int textX, int textY)

Paint clippedText at textX, textY with the labels foreground color.

See Also

protected void uninstallComponents (JLabel c)

protected void uninstallDefaults (JLabel c)

protected void uninstallKeyboardActions (JLabel c)

protected void uninstallListeners (JLabel c)