One of the new features that was introduced in Windows 2000 has been a display property which will hide the keyboard mnemonic for a menu item or a dialog control until the Alt key is pressed. In other words, all the underlined characters which represent an Alt key combination to invoke that menu or control will not be drawn until the user indicates the intention to invoke a command with the keyboard rather than the mouse. The result of this behavior is to provide an interface which is not visually cluttered with underlined characters for people who choose to navigate the user interface with the mouse.
The keyboard navigation hiding feature will be automatically enabled on Windows 2000 if the application uses the Windows look and feel and the "Hide keyboard navigation indicators until I use the Alt key" property is enabled in the Windows 2000 "Display Properties" control panel applet.
These details will be of use to developers who are extending look and feels. The keyboard navigation hiding feature will automatically be enabled when a Windows Look and Feel Java application is run on Windows 2000.
WindowsLookAndFeel is instantiated, it
will read the
"win.menu.keyboardCuesOn". This value is stored in
UIManager and can be referenced using the key:
"Button.isMnemonicHidingEnabled". The static
WindowsLookAndFeelprovide access to this value.
is responsible for rendering the background, text, icon and
mnemonic of a menu item. A new protected method,
paintText() was extracted from
paintMenuItem(), which is consistent in name and
signature to a similar method in the
paintText() methods are overloaded in
body of the overloaded
paintText method checks the
isMnemonicEnabled flag in the
WindowsLookAndFeel class to determine if the mnemonic
should be hidden and then appropriately renders the text.
BasicButtonUI already defined a protected method
similar classes overloaded this method in much the same manner. A
new class was introduced,
consolidate all the
paintText methods. This was done
because the Windows...UI classes don't follow the same inheritance
hierarchy as the Basic..UI classes.
RootPaneUI delegate called
WindowsRootPaneUI was created for the Windows look and
feel. This class had an action registered to reset the mnemonic
hidden bit and repaint the ui when the Alt key was pressed.
All these methods were added as result of implementing this feature. These methods will only have value to developers who wish to extend or create a Look and Feel.
/** * Renders the text of the current menu item. * * @param g graphics context * @param menuItem menu item to render * @param textRect bounding rectangle for rendering the text * @param text String to render * @since 1.4 */ protected void paintText(Graphics g, JMenuItem menuItem, Rectangle textRect, String text)
/** * Windows implementation of RootPaneUI. One WindowsRootPaneUI * object is shared between all JRootPane instances. * * @version 1.1 08/16/00 * @author Mark Davidson * @since 1.4 */ public class WindowsRootPaneUI extends BasicRootPaneUI
/** * A collection of static utility methods used for rendering the * Windows look and feel. * * @Version 1.1 08/16/00 * @author Mark Davidson * @since 1.4 */ public class WindowsGraphicsUtils
/** * Sets the state of the hide mnemonic flag. This flag is used by the * component UI delegates to determine if the mnemonic should be rendered. * This method is a non operation if the underlying operating system * does not support the mnemonic hiding feature. * * @param hide true if mnemonics should be hidden * @since 1.4 */ public static void setMnemonicHidden(boolean hide) /** * Gets the state of the hide mnemonic flag. This only has meaning * if this feature is supported by the underlying OS. * * @return true if mnemonics are hidden, otherwise, false * @see #setMnemonicHidden * @since 1.4 */ public static Boolean isMnemonicHidden() /** * Gets the state of the flag which indicates if the old Windows * look and feel should be rendered. This flag is used by the * component UI delegates as a hint to determine which style the component * should be rendered. * * @return true if Windows 95 and Windows NT 4 look and feel should * be rendered * @since 1.4 */ public static Boolean isClassicWindows()