Operations Dialog
The term "operation" refers to specialized callbacks that
you can define using the Visual Java operations editor.
Callbacks are typically implemented by adding custom code
to the Group file. However, for simple callbacks, it is
often more convenient to use a Visual Java operation than
to add custom code to the group class. In many cases a
Visual Java operation can automate all of the code
generation for a callback. You may find that you can use
the operations editor for all or most of your callbacks.
An operation consists of two parts: a filter and an
action. The filter is "when," and the action is
"what." For example, consider an operation that shows a
window when the user clicks a button. In this case, the
operation is defined for the button, with an event
filter of "Action Event," and an action of "Show Window."
Operations must be associated with a specific component.
Operations defined for a given component can be
triggered only by events and messages that originate from the
component itself. More than one operation can be defined
for each component. Operations are ordered, so that if two
operations match the same event, the operation closer to
the beginning of the list is invoked first.
Editing Operations Using Visual Java
The operations editor has Insert and Delete
buttons:
- Use the Insert button to create a new operation and add
it to the list of operations
- Use the Delete button to remove operations from the list.
If you accidentally delete operations, you can click Reset
to reset the list to its state after the last Apply
operation. Note that there is no undo operation, so you cannot
undo changes you have applied.
Each time you click Insert, an operation is added to the
list. Visual Java automatically assigns a unique name for
each operation you create. You can edit that name in the Op Name
field. Note that operations names must be unique within a group.
To create an operation:
- Click Insert to create the operation
- Click on the Filter button to bring up the filter
editor. This allows you to modify the filter associated
with the operations. Filters are described in Filter Editor.
- Click on the Action button to modify the operation's
action. Actions are described in Action Editor.
As you add most filters and actions you can test them
"live" in the layout window. For example, if you specify an operation that changes the foreground color of a label when a specific button is clicked, the label will change color in the layout window when the button is clicked.
Custom actions added in the
Action dialog box are available only when running the
application and are not available live in the layout panel.
See also:
- Visual Java Overview
- The Visual Menu
- Visual Java Components
- Laying Out GUI Interfaces
- Generating Java Source Code
- Adding Operations (Filters and
Actions)
- Visual Java Runtime Classes
- Creating Menus
- Adding Custom Components and Windows
- Using Groups and Shadows (Basic)
- Using Groups and Shadows (Advanced)
- Visual Java API Documentation
- Visual Java
Runtime Packages
- Class
Hierarchy
- Index of
all Fields and Methods