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},
    executor,
    keyboard::{key::Named, Event::KeyPressed, Key},
    widget::text,
    Application, Event, Settings,
};

fn main() -> iced::Result {
    MyApp::run(Settings::default())
}

#[derive(Debug, Clone)]
enum MyAppMessage {
    KeyPressed(String),
}

struct MyApp {
    pressed_key: String,
}

impl Application for MyApp {
    type Executor = executor::Default;
    type Message = MyAppMessage;
    type Theme = iced::Theme;
    type Flags = ();

    fn new(_flags: Self::Flags) -> (Self, iced::Command<Self::Message>) {
        (
            Self {
                pressed_key: "".into(),
            },
            iced::Command::none(),
        )
    }

    fn title(&self) -> String {
        String::from("My App")
    }

    fn update(&mut self, message: Self::Message) -> iced::Command<Self::Message> {
        match message {
            MyAppMessage::KeyPressed(s) => self.pressed_key = s,
        }
        iced::Command::none()
    }

    fn view(&self) -> iced::Element<Self::Message> {
        text(self.pressed_key.as_str()).into()
    }

    fn subscription(&self) -> iced::Subscription<Self::Message> {
        event::listen_with(|event, status| match (event, status) {
            (
                Event::Keyboard(KeyPressed {
                    key: Key::Named(Named::Enter),
                    ..
                }),
                Status::Ignored,
            ) => Some(MyAppMessage::KeyPressed("Enter".into())),
            (
                Event::Keyboard(KeyPressed {
                    key: Key::Named(Named::Space),
                    ..
                }),
                Status::Ignored,
            ) => Some(MyAppMessage::KeyPressed("Space".into())),
            _ => None,
        })
    }
}

➡️ Next: Producing Messages By Timers

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