javax.swing.LookAndFeel

Liking cljdoc? Tell your friends :D

Clojure only.

LookAndFeel, as the name implies, encapsulates a look and feel. Beyond installing a look and feel most developers never need to interact directly with LookAndFeel. In general only developers creating a custom look and feel need to concern themselves with this class.

Swing is built upon the foundation that each JComponent subclass has an implementation of a specific ComponentUI subclass. The ComponentUI is often referred to as "the ui", "component ui", or "look and feel delegate". The ComponentUI subclass is responsible for providing the look and feel specific functionality of the component. For example, JTree requires an implementation of the ComponentUI subclass TreeUI. The implementation of the specific ComponentUI subclass is provided by the LookAndFeel. Each JComponent subclass identifies the ComponentUI subclass it requires by way of the JComponent method getUIClassID.

Each LookAndFeel implementation must provide an implementation of the appropriate ComponentUI subclass by specifying a value for each of Swing's ui class ids in the UIDefaults object returned from getDefaults. For example, BasicLookAndFeel uses BasicTreeUI as the concrete implementation for TreeUI. This is accomplished by BasicLookAndFeel providing the key-value pair "TreeUI"-"javax.swing.plaf.basic.BasicTreeUI", in the UIDefaults returned from getDefaults. Refer to UIDefaults.getUI(JComponent) for details on how the implementation of the ComponentUI subclass is obtained.

When a LookAndFeel is installed the UIManager does not check that an entry exists for all ui class ids. As such, random exceptions will occur if the current look and feel has not provided a value for a particular ui class id and an instance of the JComponent subclass is created.

Recommendations for Look and Feels

As noted in UIManager each LookAndFeel has the opportunity to provide a set of defaults that are layered in with developer and system defaults. Some of Swing's components require the look and feel to provide a specific set of defaults. These are documented in the classes that require the specific default.

ComponentUIs and defaults

All ComponentUIs typically need to set various properties on the JComponent the ComponentUI is providing the look and feel for. This is typically done when the ComponentUI is installed on the JComponent. Setting a property should only be done if the developer has not set the property. For non-primitive values it is recommended that the ComponentUI only change the property on the JComponent if the current value is null or implements UIResource. If the current value is null or implements UIResource it indicates the property has not been set by the developer, and the ui is free to change it. For example, BasicButtonUI.installDefaults only changes the font on the JButton if the return value from button.getFont() is null or implements UIResource. On the other hand if button.getFont() returned a non-null value that did not implement UIResource then BasicButtonUI.installDefaults would not change the JButton's font.

For primitive values, such as opaque, the method installProperty should be invoked. installProperty only changes the corresponding property if the value has not been changed by the developer.

ComponentUI implementations should use the various install methods provided by this class as they handle the necessary checking and install the property using the recommended guidelines.

Exceptions

All of the install methods provided by LookAndFeel need to access the defaults if the value of the property being changed is null or a UIResource. For example, installing the font does the following:

JComponent c; Font font = c.getFont(); if (font == null || (font instanceof UIResource)) { c.setFont(UIManager.getFont("fontKey")); } If the font is null or a UIResource, the defaults table is queried with the key fontKey. All of UIDefault's get methods throw a NullPointerException if passed in null. As such, unless otherwise noted each of the various install methods of LookAndFeel throw a NullPointerException if the current value is null or a UIResource and the supplied defaults key is null. In addition, unless otherwise specified all of the install methods throw a NullPointerException if a null component is passed in.

LookAndFeel, as the name implies, encapsulates a look and
feel. Beyond installing a look and feel most developers never need to
interact directly with LookAndFeel. In general only developers
creating a custom look and feel need to concern themselves with this class.

Swing is built upon the foundation that each JComponent
subclass has an implementation of a specific ComponentUI
subclass. The ComponentUI is often referred to as "the ui",
"component ui", or "look and feel delegate". The ComponentUI
subclass is responsible for providing the look and feel specific
functionality of the component. For example, JTree requires
an implementation of the ComponentUI subclass TreeUI. The implementation of the specific ComponentUI subclass is provided by the LookAndFeel. Each
JComponent subclass identifies the ComponentUI
subclass it requires by way of the JComponent method getUIClassID.

Each LookAndFeel implementation must provide
an implementation of the appropriate ComponentUI subclass by
specifying a value for each of Swing's ui class ids in the UIDefaults object returned from getDefaults. For example,
BasicLookAndFeel uses BasicTreeUI as the concrete
implementation for TreeUI. This is accomplished by BasicLookAndFeel providing the key-value pair "TreeUI"-"javax.swing.plaf.basic.BasicTreeUI", in the
UIDefaults returned from getDefaults. Refer to
UIDefaults.getUI(JComponent) for details on how the implementation
of the ComponentUI subclass is obtained.

When a LookAndFeel is installed the UIManager does
not check that an entry exists for all ui class ids. As such,
random exceptions will occur if the current look and feel has not
provided a value for a particular ui class id and an instance of
the JComponent subclass is created.

Recommendations for Look and Feels

As noted in UIManager each LookAndFeel has the opportunity
to provide a set of defaults that are layered in with developer and
system defaults. Some of Swing's components require the look and feel
to provide a specific set of defaults. These are documented in the
classes that require the specific default.

ComponentUIs and defaults

All ComponentUIs typically need to set various properties
on the JComponent the ComponentUI is providing the
look and feel for. This is typically done when the ComponentUI is installed on the JComponent. Setting a
property should only be done if the developer has not set the
property. For non-primitive values it is recommended that the
ComponentUI only change the property on the JComponent if the current value is null or implements
UIResource. If the current value is null or
implements UIResource it indicates the property has not
been set by the developer, and the ui is free to change it.  For
example, BasicButtonUI.installDefaults only changes the
font on the JButton if the return value from button.getFont() is null or implements UIResource. On the other hand if button.getFont() returned
a non-null value that did not implement UIResource
then BasicButtonUI.installDefaults would not change the
JButton's font.

For primitive values, such as opaque, the method installProperty should be invoked.  installProperty only changes
the corresponding property if the value has not been changed by the
developer.

ComponentUI implementations should use the various install methods
provided by this class as they handle the necessary checking and install
the property using the recommended guidelines.

Exceptions

All of the install methods provided by LookAndFeel need to
access the defaults if the value of the property being changed is
null or a UIResource. For example, installing the
font does the following:


  JComponent c;
  Font font = c.getFont();
  if (font == null || (font instanceof UIResource)) {
      c.setFont(UIManager.getFont("fontKey"));
  }
If the font is null or a UIResource, the
defaults table is queried with the key fontKey. All of
UIDefault's get methods throw a NullPointerException if passed in null. As such, unless
otherwise noted each of the various install methods of LookAndFeel throw a NullPointerException if the current
value is null or a UIResource and the supplied
defaults key is null. In addition, unless otherwise specified
all of the install methods throw a NullPointerException if
a null component is passed in.

javax.swing.LookAndFeel

*get-desktop-property-valueclj

*install-borderclj

*install-colorsclj

*install-colors-and-fontclj

*install-propertyclj

*load-key-bindingsclj

*make-component-input-mapclj

*make-iconclj

*make-input-mapclj

*make-key-bindingsclj

*uninstall-borderclj

->look-and-feelclj

get-defaultsclj

get-descriptionclj

get-disabled-iconclj

get-disabled-selected-iconclj

get-idclj

get-layout-styleclj

get-nameclj

get-supports-window-decorations?clj

initializeclj

native-look-and-feel?clj

provide-error-feedbackclj

supported-look-and-feel?clj

to-stringclj

uninitializeclj

*get-desktop-property-value^clj

*install-border^clj

*install-colors^clj

*install-colors-and-font^clj

*install-property^clj

*load-key-bindings^clj

*make-component-input-map^clj

*make-icon^clj

*make-input-map^clj

*make-key-bindings^clj

*uninstall-border^clj

->look-and-feel^clj

get-defaults^clj

get-description^clj

get-disabled-icon^clj

get-disabled-selected-icon^clj

get-id^clj

get-layout-style^clj

get-name^clj

get-supports-window-decorations?^clj

initialize^clj

native-look-and-feel?^clj

provide-error-feedback^clj

supported-look-and-feel?^clj

to-string^clj

uninitialize^clj