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Users invoke online help from within applications in a number of ways. This section describes invocation methods available through the JavaHelp system.
Online help is often invoked when a user chooses an item from a Help menu or clicks on a Help button in an application GUI.
The JavaHelp system provides a simple interface by which an application requests that a topic ID be displayed. The JavaHelp system then associates the topic ID with the appropriate URL and displays it. IDs are mapped to URLs in a JavaHelp system metadata file called the map file.
For example, when coding a file chooser dialog box, a
developer requests that the topic ID fc_help
be displayed when the Help button at the bottom of the
dialog box is clicked. In the map file the ID
fc_help is defined to be a file named
FileChooser.html using the following XML syntax:
<mapID target="fc_help" url="html/help/FileChooser.html" />
Separating the specification of file names (or URLs) from the program code provides content authors the freedom to control the information that is associated with the topic ID.
A tooltip is a brief message presented to the user when the cursor remains over a button for an interval longer than a given threshold.
Although tooltip information could be included in the JavaHelp system data, it will usually be delivered as part of the application and will be co-located with the code. Tooltip functionality is provided as a component in Swing.
The JavaHelp system provides the ability to invoke online help that describes graphical components in an application GUI. The user makes gestures that activate context-sensitive help and then specifies the component in question. The ID associated with the component is displayed.
You can display help topics from a TOC or index navigator or from the content pane of the main window. By default, an index entry and a TOC entry display help in the main window's content viewer. You can also define an entry that displays help in a popup or a secondary window. In the content pane, you can define an <object> tag that displays help in a separate popup or secondary window. If you use a standard HTML link in the content pane, the linked help topic replaces the current one in the content pane.
The following invocation would display system-initiated help in a main window.
mainHelpBroker.setCurrentID(helpID);
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