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BasicLabelUI (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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javax.swing.plaf.basic
Class BasicLabelUI

java.lang.Object
  extended by javax.swing.plaf.ComponentUI
      extended by javax.swing.plaf.LabelUI
          extended by javax.swing.plaf.basic.BasicLabelUI
All Implemented Interfaces:
PropertyChangeListener, EventListener
Direct Known Subclasses:
MetalLabelUI
public class BasicLabelUI
extends LabelUI
implements PropertyChangeListener

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.

Field Summary
protected static BasicLabelUI labelUI
          The default BasicLabelUI instance.
 
Constructor Summary
BasicLabelUI()
           
 
Method Summary
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.
protected  void installComponents(JLabel c)
           
protected  void installDefaults(JLabel c)
           
protected  void installKeyboardActions(JLabel l)
           
protected  void installListeners(JLabel c)
           
 void installUI(JComponent c)
          Configures the specified component appropriate for the look and feel.
protected  String layoutCL(JLabel label, FontMetrics fontMetrics, String text, Icon icon, Rectangle viewR, Rectangle iconR, Rectangle textR)
          Forwards the call to SwingUtilities.layoutCompoundLabel().
 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.
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().
protected  void paintEnabledText(JLabel l, Graphics g, String s, int textX, int textY)
          Paint clippedText at textX, textY with the labels foreground color.
 void propertyChange(PropertyChangeEvent e)
          This method gets called when a bound property is changed.
protected  void uninstallComponents(JLabel c)
           
protected  void uninstallDefaults(JLabel c)
           
protected  void uninstallKeyboardActions(JLabel c)
           
protected  void uninstallListeners(JLabel c)
           
 void uninstallUI(JComponent c)
          Reverses configuration which was done on the specified component during installUI.
 
Methods inherited from class javax.swing.plaf.ComponentUI
contains, getAccessibleChild, getAccessibleChildrenCount, update
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

labelUI

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".

Constructor Detail

BasicLabelUI

public BasicLabelUI()
Method Detail

layoutCL

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:
SwingUtilities.layoutCompoundLabel(javax.swing.JComponent, java.awt.FontMetrics, java.lang.String, javax.swing.Icon, int, int, int, int, java.awt.Rectangle, java.awt.Rectangle, java.awt.Rectangle, int)

paintEnabledText

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:
paint(java.awt.Graphics, javax.swing.JComponent), paintDisabledText(javax.swing.JLabel, java.awt.Graphics, java.lang.String, int, int)

paintDisabledText

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:
paint(java.awt.Graphics, javax.swing.JComponent), paintEnabledText(javax.swing.JLabel, java.awt.Graphics, java.lang.String, int, int)

paint

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.

Overrides:
paint in class ComponentUI
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:
paintEnabledText(javax.swing.JLabel, java.awt.Graphics, java.lang.String, int, int), paintDisabledText(javax.swing.JLabel, java.awt.Graphics, java.lang.String, int, int), layoutCL(javax.swing.JLabel, java.awt.FontMetrics, java.lang.String, javax.swing.Icon, java.awt.Rectangle, java.awt.Rectangle, java.awt.Rectangle)

getPreferredSize

public Dimension getPreferredSize(JComponent c)
Description copied from class: ComponentUI
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.

Overrides:
getPreferredSize in class ComponentUI
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
See Also:
JComponent.getPreferredSize(), LayoutManager.preferredLayoutSize(java.awt.Container)

getMinimumSize

public Dimension getMinimumSize(JComponent c)
Description copied from class: ComponentUI
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.

Overrides:
getMinimumSize in class ComponentUI
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)
See Also:
JComponent.getMinimumSize(), LayoutManager.minimumLayoutSize(java.awt.Container), ComponentUI.getPreferredSize(javax.swing.JComponent)

getMaximumSize

public Dimension getMaximumSize(JComponent c)
Description copied from class: ComponentUI
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.

Overrides:
getMaximumSize in class ComponentUI
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)
See Also:
JComponent.getMaximumSize(), LayoutManager2.maximumLayoutSize(java.awt.Container)

getBaseline

public int getBaseline(JComponent c,
                       int width,
                       int height)
Returns the baseline.

Overrides:
getBaseline in class ComponentUI
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 - if c is null
IllegalArgumentException - if width or height is < 0
Since:
1.6
See Also:
JComponent.getBaseline(int, int)

getBaselineResizeBehavior

public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
Returns an enum indicating how the baseline of the component changes as the size changes.

Overrides:
getBaselineResizeBehavior in class ComponentUI
Parameters:
c - JComponent to return baseline resize behavior for
Returns:
an enum indicating how the baseline changes as the component size changes
Throws:
NullPointerException - if c is null
Since:
1.6
See Also:
JComponent.getBaseline(int, int)

installUI

public void installUI(JComponent c)
Description copied from class: ComponentUI
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.

Overrides:
installUI in class ComponentUI
Parameters:
c - the component where this UI delegate is being installed
See Also:
ComponentUI.uninstallUI(javax.swing.JComponent), JComponent.setUI(javax.swing.plaf.ComponentUI), JComponent.updateUI()

uninstallUI

public void uninstallUI(JComponent c)
Description copied from class: ComponentUI
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.

Overrides:
uninstallUI in class ComponentUI
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
See Also:
ComponentUI.installUI(javax.swing.JComponent), JComponent.updateUI()

installDefaults

protected void installDefaults(JLabel c)

installListeners

protected void installListeners(JLabel c)

installComponents

protected void installComponents(JLabel c)

installKeyboardActions

protected void installKeyboardActions(JLabel l)

uninstallDefaults

protected void uninstallDefaults(JLabel c)

uninstallListeners

protected void uninstallListeners(JLabel c)

uninstallComponents

protected void uninstallComponents(JLabel c)

uninstallKeyboardActions

protected void uninstallKeyboardActions(JLabel c)

createUI

public static ComponentUI createUI(JComponent c)

propertyChange

public void propertyChange(PropertyChangeEvent e)
Description copied from interface: PropertyChangeListener
This method gets called when a bound property is changed.

Specified by:
propertyChange in interface PropertyChangeListener
Parameters:
e - A PropertyChangeEvent object describing the event source and the property that has changed.
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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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