JSF 1.1 Radio Button Component

See Also | Tutorials

You can drag the Radio Button component radio button component icon from the Palette's Basic category to the Visual Designer to create a single radio button with an optional label.

Radio Button components are typically used in a group. If you want a set of radio buttons that is preformatted with labels, use a Radio Button Group component instead.

You can also drop the radio button on a container component, like a table cell or group box.

A radio button can represent any object, whether the object is of a predefined class like Boolean, Byte, Character, Double, Float, Integer, Long, Short, String, or of a class defined by the user. A radio button can also represent a primitive value.

A Boolean value is useful for indicating whether an item, such as a table row, is selected. A String value is useful for passing values for radio button selections made in the interface. An application defined Object value or class instance can be used to hold more information related to a radio button selection.

A single radio button can be used to represent several types of data:

A group of radio buttons can be used to represent:

The radio button component can be useful in situations where the Radio Button Group component layout is not desirable, such as in a table row.

Detecting a Selected Radio Button

The radio button component uses both the selected and selectedValue properties to pass information about the radio button's selection status. The selected property is used to indicate that the radio button is selected, and an indication that the button is selected is displayed in the page. The selectedValue property is used to pass a data value for the radio button. A radio button is considered to be selected when the value of the selected property is equal to the value of the selectedValue property. You can display a radio button as selected on the initial viewing of the page by assigning the same value to the selectedValue and the selected properties.

If the selectedValue property is not specified or its value is null, the radio button behaves like a boolean control, as described in the next section.

A value binding expression that evaluates to a primitive value can be assigned to the selected and selectedValue properties.

Using a Radio Button Component as a Boolean Control

If the selectedValue property is not specified or its value is null, the radio button behaves like a boolean control.

To use the radio button as a boolean control, do not specify a value for the selectedValue property. The radio button is selected if the selected property is not null and has the value of a true Boolean instance or a boolean primitive value. If the radio button is not selected, the value of the selected property is a false Boolean instance or boolean primitive.

Using a Radio Button to Represent an Application-defined Value

The selectedValue property can be assigned an application-defined object value to represent the value of a selected radio button. If the radio button is selected, the value of the selected property is assigned the value of the selectedValue property.

If the value of the selectedValue property is an application-defined object, a converter must be registered to convert to and from a String value. The converter is used to encode the radio button value as the value of the HTML <input> element and to decode the submitted value in a request. In addition the object must support an equals() method that returns true when the value of the selectedValue property is compared to the selected property value to detect a selected radio button.

Using a Radio Button as one control in a group

The name property determines whether a radio button is part of a group. All radio buttons in a group have the same name property value. The group behaves like a single selection list in which only one radio button can be selected. The value of the name property must be unique within the scope of the page containing the radio buttons.

See Also
Radio Button Component Properties Window
Binding Component Properties
Working With Components
Component Tasks: Quick Reference
About the Visual Web Palette
Tutorials

Legal Notices