Trait Program

pub trait Program: Sized {
    type Renderer: Renderer;
    type Theme;
    type Message: Debug + Send;

    // Required methods
    fn update(&mut self, message: Self::Message) -> Task<Self::Message>;
    fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer>;
}

The core of a user interface application following The Elm Architecture.

Required Associated Types

type Renderer: Renderer

The graphics backend to use to draw the Program.

type Theme

The theme used to draw the Program.

type Message: Debug + Send

The type of messages your Program will produce.

Required Methods

fn update(&mut self, message: Self::Message) -> Task<Self::Message>

Handles a message and updates the state of the Program.

This is where you define your update logic. All the messages, produced by either user interactions or commands, will be handled by this method.

Any Task returned will be executed immediately in the background by shells.

fn view(&self) -> Element<'_, Self::Message, Self::Theme, Self::Renderer>

Returns the widgets to display in the Program.

These widgets can produce messages based on user interaction.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors