The Property Sheet
To display the property sheet for a component, either double-click on it,
or select it and then select Properties from the Object menu or
the Property Sheet icon (
) from
the toolbar.
To change a property simply click on the property. At the bottom of
the window the edit area will appear and allow you to set the property.
There are three common properties of each component: Variable Name,
Variable Scope, and Object Initialization.
Variable name is the name used to refer to the component in the
generated code.
Variable scope provides a means of controlling the declaration
scope of a component. If Instance variable is selected, then you
are offered the choice of access restrictions.
Object Initialization enables you to control the way in which
the object is initialized. You can choose between:
- New
- Beans instantiation
- Code Expression
- Variable Name
- No Initialisation
- Deserialization
For other properties the Choice box at the top of the edit area will
usually offer three ways to specify the property:
- Value
- Code Expression
- Variable Name
For properties whose type is java.awt.Image or com.sun.java.swing.Icon there
is an additional specification called Image resource or
Swing ImageIcon resource.
New
This is the default for object initialisation, and results in the object
being initialised via the use of new
.
Beans instantiation
This results in the object being initialised via the use of
Beans.instantiate()
.
No Initialization
This means that no initialization code is generated for the object. This
allows you to reference an object that is created within another method.
Deserialization
This results in the object being created from a serialized file. Note
that this option is not available for Swing components that are
composites, e.g. JFrame. For more details see deserialization.
Value
This is where a simple value is used to set the property. If you were
setting a label property on a Button, then you would enter text here. If
on the other hand, you were setting a boolean (True/False) value (e.g.
Resizable on a Frame), then a choice would be offered to you of either
True or False. Many of the properties in the Property Sheet have their
own way of setting their properties. Examples of these are: size,
foreground, and font.
You will find that third party components will provide their own way
of setting the properties on their components.
Variable Name
Here you may specify the name
of a variable, of the same type, to set this property. An example of
when you might do this is with CheckboxGroups.
The variable name is not used dynamically inside Visaj yet, but you
will see its effect when the generated code is run.
Code Expression
You may enter any valid Java
code expression which returns a value of the correct type. You may use
this when the property depends on the property of another component, e.g.
for making the 'title' of a Frame equal to the 'label' of the Button that
was just pressed:
selectedButton.getLabel()
Again, the code expression is not used dynamically inside Visaj, but
you will see its effect when the generated code is run.
Image resource and Swing ImageIcon resource
Both of these allow you to specify image resources. You specify a file that
is used by the dynamic display in the Design-time file: field, and a
resource path that is used in the generated code in the Runtime resource
path: field. For more details please see the Visaj User's Guide.
Reset to Default Value
At the bottom of the editing area there is a Reset to default
value button. If you have changed the selected value in the property
sheet, Reset to Default Value sets the value back to the default.
Undo and Close
At the bottom of the property sheet there is an Undo button and
a Close button.
Undo undoes the last change made in the current property sheet.
Close closes the property sheet.