| A tag interface that is used in the generation of image bundles. An image
bundle is a composition of multiple images into a single large image, along
with an interface for accessing a specific image's
com.google.gwt.user.client.ui.AbstractImagePrototype prototype from
within the composition. Obtain an image bundle instance by calling
GWT.create(T), where T is an
interface that directly or indirectly extends ImageBundle.
To create and use an image bundle, extend the ImageBundle
interface, and add a method declaration for each image that is to be part of
the bundle. Each method must take no parameters and must have a return type
of
com.google.gwt.user.client.ui.AbstractImagePrototype AbstractImagePrototype .
The image name can optionally be specified using the
gwt.resource metadata tag. Valid image name extensions are
png, gif, or jpg. If the
image name contains '/' characters, it is assumed to be the name of a
resource on the classpath, formatted as would be expected by
ClassLoader.getResource(String).
Otherwise, the image must be located in the same package as the user-defined
image bundle.
The easiest way to create an image bundle is to omit the
gwt.resource metadata tag, and name the method the same as the
image name, excluding the extension. When the image name is inferred in this
manner, the image name's extension is assumed to be either png,
gif, or jpg, and the image location must be
in the same package as the user-defined image bundle. In the event that there
are multiple image files that have the same name with different extensions,
the order of extension precedence is png, gif,
jpg.
Example
public interface MyImageBundle extends ImageBundle {
/**
Notice that the gwt.resource metadata tag is not present,
so the method name itself is assumed to match the associated
image filename.
One of btn_submit_icon.png, btn_submit_icon.gif, or
btn_submit_icon.jpg must be located in the same package
as MyImageBundle.
/
public AbstractImagePrototype btn_submit_icon();
// No doc comment is required if you want the default
// name-matching behavior.
public AbstractImagePrototype cancelButtonIcon();
}
An image bundle that uses the gwt.resource metadata tag to
specify image names might look something like this:
public interface MyImageBundle extends ImageBundle {
/**
The metadata tag contains no '/' characters, so
btn_submit_icon.gif must be located in the same
package as MyImageBundle.
See Also: com.google.gwt.user.client.ui.AbstractImagePrototype
See Also: com.google.gwt.user.client.ui.Image.Image(Stringintintintint)
See Also: com.google.gwt.user.client.ui.Image.setVisibleRect(intintintint)
See Also: com.google.gwt.user.client.ui.Image.setUrlAndVisibleRect(Stringintintintint) |