Plug-Ins - Expert Oracle Application Express - page 441

attributes which are then exposed to plug-in users as settings (see Figure 11-9). To add an attribute to a
plug-in, simply click the Add Attribute button. This will redirect you to the Edit Attribute page where the
attribute can be configured.
Figure 11-9. The Custom Attributes region of the Create/Edit page
Custom attributes can be displayed as a number of different element types and be made to display
conditionally (based on the value of another custom attribute). Currently you can create up to ten
custom attributes at the application level and another ten custom attributes at the component level. The
number of custom attributes available will likely increase with future releases of APEX—this will help
make more sophisticated plug-ins with declarative options that are easy to use.
Placing attributes at the application level of a plug-in is a good way to reduce the number of
decisions that plug-in users face each time they use a plug-in and it's a good way to enforce consistency.
For example, an attribute that changes the color scheme of a plug-in may be best at the application level
so that the plug-in is displayed the same way on different pages.
On the other hand, not all attributes are suited for the application level. An attribute used to identify
a page level item may be better off as a component-level attribute. This would allow the plug-in to be
used more than once in an application without different instances of the plug-in interfering with each
other.
The Custom Attributes region is only available after the plug-in is created. Also, certain parts of
custom attributes, such as the Scope, Attribute (number), and LOV return values, cannot be modified if
the plug-in is being used in the application.