producing_messages_by_keyboard_events.md

Producing Messages By Keyboard Events

This tutorial follows from the previous tutorial. Instead of capturing Event::Mouse and Event::Touch, we capture Event::Keyboard in the listen_with function.

use iced::{
    event::{self, Status},
    keyboard::{key::Named, Event::KeyPressed, Key},
    widget::text,
    Element, Event, Subscription, Task,
};

fn main() -> iced::Result {
    iced::application(
        "producing_messages_by_keyboard_events",
        MyApp::update,
        MyApp::view,
    )
    .subscription(MyApp::subscription)
    .run()
}

struct MyApp {
    pressed_key: String,
}

impl Default for MyApp {
    fn default() -> Self {
        MyApp::new()
    }
}

#[derive(Debug, Clone)]
enum Message {
    KeyPressed(String),
}
  
impl MyApp {
    fn new() -> Self {
        Self {
            pressed_key: String::new(),
        }
    }
  
    fn update(&mut self, message: Message) -> Task<Message> {
        match message {
            Message::KeyPressed(s) => {
                self.pressed_key = s;
                return Task::none();
            }
        }
    }

    fn view(&self) -> Element<Message> {
        text(self.pressed_key.as_str()).into()
    }
  
    fn subscription(&self) -> Subscription<Message> {
        event::listen_with(|event, status, _window| match (event, status) {
            (
                Event::Keyboard(KeyPressed {
                    key: Key::Named(Named::Space),
                    ..
                }),
                Status::Ignored,
            ) => Some(Message::KeyPressed("Space".into())),
            _ => None,
        })
    }
}

➡️ Next: Producing Messages By Timers

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