Rust Programming By Example

Emit

So, let's see how to send a message to the same widget without using this syntax: this is useful in more complex cases, such as when we want to conditionally send a message. Let's go back to our Playlist and add a play() method:

impl Playlist {
    fn play(&mut self) {
        if let Some(path) = self.selected_path() {
            self.model.current_song = Some(path.into());
            self.model.relm.stream().emit(SongStarted(self.pixbuf()));
        }
    }
}

This line sends a message to the current widget:

self.model.relm.stream().emit(SongStarted(self.pixbuf()));

We first get the event stream from the relm widget and then call emit() on it with a message. This play() method requires two new methods:

use gtk::{
    TreeModelExt,
    TreeSelectionExt,
};

impl Playlist {
    fn pixbuf(&self ...