Extending existing widgets
The standard widgets that we explored in Chapter 5, Widget Library and Themes, all have minimal APIs to define commonly required functionality. To support the addition of more advanced functionality, each Fyne widget can be extended by application developers. In this section, we will see how widgets can be enhanced by overriding their existing functionality or adding new behavior.
As we can see in the following diagram, extended widgets, as well as custom widgets, can be included in a container alongside standard widgets and canvas objects:
Figure 7.1 – Extended and custom widgets can be used alongside standard elements
An extended widget will embed an existing widget and provide replacement, or enhanced, functionality around it. Custom widgets, which we will see later in this chapter, implement the complete Widget interface, and so are not constrained by the designs of a standard widget.
Building custom widgets offers...
