changing_displaying_content.md

Changing Displaying Content

To change the content in view dynamically, we can do the following:

• Add some fields (e.g., counter) to the main struct MyApp.
• Display the fields in view (e.g., text(self.counter)).
• Produce some messages in view (e.g., button(...).on_press(MyAppMessage::ButtonPressed)).
• Update the fields when messages are received in update (e.g., self.counter += 1).

use iced::{
    widget::{button, column, text},
    Sandbox, Settings,
};

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

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

struct MyApp {
    counter: usize,
}

impl Sandbox for MyApp {
    type Message = MyAppMessage;

    fn new() -> Self {
        Self { counter: 0 }
    }

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

    fn update(&mut self, message: Self::Message) {
        match message {
            MyAppMessage::ButtonPressed => self.counter += 1,
        }
    }

    fn view(&self) -> iced::Element<Self::Message> {
        column![
            text(self.counter),
            button("Increase").on_press(MyAppMessage::ButtonPressed),
        ]
        .into()
    }
}

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