Rust Programming By Example

Creating custom widgets

In object-oriented languages, it is very easy to create new widgets and use them like built-in widgets. In this paradigm, you only need to create a new class that inherits from a widget and that's it.

In Chapter 5, Creating a Music Player, we created custom widgets, such as Playlist and MusicToolbar, but we needed to create a function to get the real GTK+ widget:

pub fn view(&self) -> &TreeView {
    &self.treeview
}

An alternative would have been to implement the Deref trait:

use std::ops::Deref;

impl Deref for Playlist {
    type Target = TreeView;

    fn deref(&self) -> &TreeView {
        &self.treeview
    }
}

That implementation would allow us to add the widget to its parent like this:

parent.add(&*playlist);

(Note the leading * in ...