javax.swing. A
* cross-platform look-and-feel (the {@link MetalLookAndFeel}) is provided.
*
* @see UIManager#getInstalledLookAndFeels()
* @see UIManager#setLookAndFeel(LookAndFeel)
*/
public abstract class LookAndFeel
{
/**
* Creates and returns a look-and-feel specific defaults table. This method
* is called once by {@link UIManager#setLookAndFeel(LookAndFeel)} and
* shouldn't be called again (as it creates a large table of defaults).
*
* @return The UI defaults.
*/
public UIDefaults getDefaults()
{
return null;
}
/**
* Returns a description of the look and feel.
*
* @return A description of the look and feel.
*/
public abstract String getDescription();
/**
* Returns the value of Toolkit.getDefaultToolkit()
* .getDesktopProperty(systemPropertyName), or
* fallbackValue if no such property is defined.
*
* @param systemPropertyName the system property name.
* @param fallbackValue the fallback value.
*
* @return The property value or fallbackValue.
*/
public static Object getDesktopPropertyValue(String systemPropertyName,
Object fallbackValue)
{
Object value = Toolkit.getDefaultToolkit().getDesktopProperty(
systemPropertyName);
return value != null ? value : fallbackValue;
}
/**
* Returns an identifier for the look and feel.
*
* @return An identifier for the look and feel.
*/
public abstract String getID();
/**
* Returns the name for the look and feel.
*
* @return The name for the look and feel.
*/
public abstract String getName();
/**
* Returns true when the look-and-feel supports window
* decorations, and false otherwise. This default implementation
* always returns false and needs to be overridden when the
* derived look-and-feel supports this.
*
* @return false.
*
* @since 1.4
*/
public boolean getSupportsWindowDecorations()
{
return false;
}
/**
* Initializes the look-and-feel. The
* {@link UIManager#setLookAndFeel(LookAndFeel)} method calls this method
* before the first call (and typically the only call) to
* {@link #getDefaults()}. This default implementation does nothing, but
* subclasses can override this behaviour.
*/
public void initialize()
{
// We do nothing here. This method is meant to be overridden by
// LookAndFeel implementations.
}
/**
* Convenience method for installing a component's default {@link Border}
* object on the specified component if either the border is currently
* null or already an instance of {@link UIResource}.
*
* @param c the component (null not permitted).
* @param defaultBorderName the border name (for lookup in the UIDefaults
* table).
*/
public static void installBorder(JComponent c, String defaultBorderName)
{
Border b = c.getBorder();
if (b == null || b instanceof UIResource)
c.setBorder(UIManager.getBorder(defaultBorderName));
}
/**
* Convenience method for initializing a component's foreground and
* background color properties with values from the current defaults table.
*
* @param c the component (null not permitted).
* @param defaultBgName the key for the background color in the UIDefaults
* table.
* @param defaultFgName the key for the foreground color in the UIDefaults
* table.
*/
public static void installColors(JComponent c, String defaultBgName,
String defaultFgName)
{
// Install background.
Color bg = c.getBackground();
if (bg == null || bg instanceof UIResource)
c.setBackground(UIManager.getColor(defaultBgName));
// Install foreground.
Color fg = c.getForeground();
if (fg == null || fg instanceof UIResource)
c.setForeground(UIManager.getColor(defaultFgName));
}
/**
* Convenience method for initializing a component's foreground, background
* and font properties with values from the current defaults table.
*
* @param component the component (null not permitted).
* @param defaultBgName the key for the background color in the UIDefaults
* table.
* @param defaultFgName the key for the foreground color in the UIDefaults
* table.
* @param defaultFontName the key for the font in the UIDefaults table.
*/
public static void installColorsAndFont(JComponent component,
String defaultBgName,
String defaultFgName,
String defaultFontName)
{
// Install colors.
installColors(component, defaultBgName, defaultFgName);
// Install font.
Font f = component.getFont();
if (f == null || f instanceof UIResource)
component.setFont(UIManager.getFont(defaultFontName));
}
/**
* Returns true if the look-and-feel is the "native"
* look-and-feel for the current platform, and false otherwise.
* A native look-and-feel emulates the appearance and behaviour of the
* default windowing system on the host operating system.
*
* @return A flag indicating whether or not this is the native look and feel
* for the current platform.
*/
public abstract boolean isNativeLookAndFeel();
/**
* Returns true if the look-and-feel is supported on the
* current operating system, and false otherwise. This
* mechanism is provided so that it is possible to prevent a look-and-feel
* from being used on some operating systems (usually for legal, not
* technical, reasons).
*
* @return A flag indicating whether or not the look-and-feel is supported
* on the current platform.
*/
public abstract boolean isSupportedLookAndFeel();
/**
* Loads the bindings in keys into retMap. Does not remove existing entries
* from retMap. keys describes the InputMap, every even indexed
* item is either a KeyStroke or a String representing a KeyStroke and every
* odd indexed item is the Object associated with that KeyStroke in an
* ActionMap.
*
* @param retMap the InputMap into which we load bindings
* @param keys the Object array describing the InputMap as above
*/
public static void loadKeyBindings(InputMap retMap, Object[] keys)
{
if (keys == null)
return;
for (int i = 0; i < keys.length - 1; i += 2)
{
Object key = keys[i];
KeyStroke keyStroke;
if (key instanceof KeyStroke)
keyStroke = (KeyStroke) key;
else
keyStroke = KeyStroke.getKeyStroke((String) key);
retMap.put(keyStroke, keys[i + 1]);
}
}
/**
* Creates a ComponentInputMap from keys.
* keys describes the InputMap, every even indexed
* item is either a KeyStroke or a String representing a KeyStroke and every
* odd indexed item is the Object associated with that KeyStroke in an
* ActionMap.
*
* @param c the JComponent associated with the ComponentInputMap
* @param keys the Object array describing the InputMap as above
*
* @return A new input map.
*/
public static ComponentInputMap makeComponentInputMap(JComponent c,
Object[] keys)
{
ComponentInputMap retMap = new ComponentInputMapUIResource(c);
loadKeyBindings(retMap, keys);
return retMap;
}
/**
* Utility method that creates a UIDefaults.LazyValue that creates an
* ImageIcon UIResource for the specified gifFile filename.
*
* @param baseClass the base class for accessing the icon resource.
* @param gifFile the file name.
*
* @return A {@link UIDefaults.LazyValue} that serves up an
* {@link IconUIResource}.
*/
public static Object makeIcon(Class baseClass, String gifFile)
{
final URL file = baseClass.getResource(gifFile);
return new UIDefaults.LazyValue()
{
public Object createValue(UIDefaults table)
{
return new IconUIResource(new ImageIcon(file));
}
};
}
/**
* Creates a InputMap from keys.
* keys describes the InputMap, every even indexed
* item is either a KeyStroke or a String representing a KeyStroke and every
* odd indexed item is the Object associated with that KeyStroke in an
* ActionMap.
*
* @param keys the Object array describing the InputMap as above
*
* @return A new input map.
*/
public static InputMap makeInputMap(Object[] keys)
{
InputMap retMap = new InputMapUIResource();
loadKeyBindings(retMap, keys);
return retMap;
}
/**
* Convenience method for building lists of KeyBindings.
* keyBindingList is an array of KeyStroke-Action pairs where
* even indexed elements are KeyStrokes or Strings representing KeyStrokes
* and odd indexed elements are the associated Actions.
*
* @param keyBindingList the array of KeyStroke-Action pairs
* @return a JTextComponent.KeyBinding array
*/
public static JTextComponent.KeyBinding[] makeKeyBindings(
Object[] keyBindingList)
{
JTextComponent.KeyBinding[] retBindings =
new JTextComponent.KeyBinding[keyBindingList.length / 2];
for (int i = 0; i < keyBindingList.length - 1; i += 2)
{
KeyStroke stroke;
if (keyBindingList[i] instanceof KeyStroke)
stroke = (KeyStroke) keyBindingList[i];
else
stroke = KeyStroke.getKeyStroke((String) keyBindingList[i]);
retBindings[i / 2] = new JTextComponent.KeyBinding(stroke,
(String) keyBindingList[i + 1]);
}
return retBindings;
}
/**
* Invoked when the user attempts an invalid operation. The default
* implementation just beeps. Subclasses that wish to change this need to
* override this method.
*
* @param component the component the error occured in
*/
public void provideErrorFeedback(Component component)
{
Toolkit.getDefaultToolkit().beep();
}
/**
* Returns a string that displays and identifies this object's properties.
*
* @return string containing the description and class name.
*/
public String toString()
{
return getDescription() + " " + getClass().getName();
}
/**
* UIManager.setLookAndFeel calls this method just before we're replaced by
* a new default look and feel.
*/
public void uninitialize()
{
// We do nothing here. This method is meant to be overridden by
// LookAndFeel implementations.
}
/**
* Convenience method for un-installing a component's default border on the
* specified component if the border is currently an instance of UIResource.
*
* @param c the component (null not permitted).
*/
public static void uninstallBorder(JComponent c)
{
if (c.getBorder() instanceof UIResource)
c.setBorder(null);
}
/**
* This methods installs a UI property if it hasn't already been set by an
* application. This method is used by UI delegates that install a default
* value for a property with a primitive type but do not want to override
* a value that has been set by an application.
*
* The supported properties depend on the actual type of the component and
* are listed in the table below. The supported properties are of course
* inherited to subclasses.
*
* | Type | Supported properties |
|---|---|
JComponent |
* opaque, autoscrolls |
AbstractButton |
* borderPainted, rolloverEnabled, iconTextGap,
* contentAreaFilled |
JDesktopPane |
* dragMode |
JSplitPane |
* dividerSize, oneTouchExpandable |
JTable |
* rowHeight |
JTree |
* rowHeight, scrollsOnExpand, showsRootHandles |
c or
* propertyValue is null
*
* @since 1.5
*/
public static void installProperty(JComponent c, String propertyName,
Object value)
{
c.setUIProperty(propertyName, value);
}
}