widget-types.rst

Widget Types

While Widget is pretty straightforward as far as the interface is concerned, there are several intermediate implementations to make it easier to define the widget.

Class	Description
AbstractWidget	Implements getProperties(), getSources(), and titleProperty()
SingleTypeWidget<T>	Adds properties for widgets that only support a single data type
AnnotatedWidget	Adds default implementations for getName() and getDataTypes() for widgets with a @Description annotation
SingleSourceWidget	For widgets with only a single source (by default, widgets support multiple sources)
SimpleAnnotatedWidget<T>	Combines SingleTypeWidget<T>, AnnotatedWidget, and SingleSourceWidget

There are also two annotations to help define widgets:

Name	Description
@ParametrizedController	Allows widgets to be FXML controllers for JavaFX views defined via FXML
@Description	Lets the name and supported data types be defined in a single line

AbstractWidget

This class implements getProperties(), getSources(), addSource(), and titleProperty(). It also defines a method exportProperties(Property<?>...) method so subclasses can easy add custom widget properties, or properties for the JavaFX components in the widget. Most of the widgets in the base plugin use this.

SingleTypeWidget

A type of widget that only supports a single data type. This interface is parametrized and has methods for setting or getting the data, as well as a method for getting the (single) data type of the widget.

AnnotatedWidget

This interface implements getDataTypes() and getName() by looking at the the @Description annotation on the implementing class. This requires the annotation to be present, or the widget will not be able to be loaded and used.

// No @Description annotation!
public class WrongImplementation implements AnnotatedWidget {
  // ...
}

@Description(name = ..., dataTypes = ...)
public class CorrectImplementation implements AnnotatedWidget {
  // ...
}

SingleSourceWidget

A type of widget that only uses a single source.

SimpleAnnotatedWidget

A combination of SingleTypeWidget<T>, AnnotatedWidget, and SingleSourceWidget. Most widgets in the base plugin extend from this class. This also has a protected field called dataOrDefault that lets subclasses use a default data value if the widget doesn’t have a source, or if the source is providing null.

@ParametrizedController

This annotation can be placed on a widget class to let shuffleboard know that it’s an FXML controller for a JavaFX view defined via FXML. The annotation takes a single parameter that defines where the FXML file in relation to the class on which it is placed. For example, a widget in the directory src/main/java/com/acme that is an FXML controller for a FXML file in src/main/resources/com/acme can use the annotation as either

@ParametrizedController("MyWidget.fxml")

or as

@ParametrizedController("/com/acme/MyWidget.fxml")

@Description

This allows widgets to have their name and supported data types defined by a single annotation, when used alongside AnnotatedWidget.