diff options
Diffstat (limited to 'src/lib.rs')
| -rw-r--r-- | src/lib.rs | 30 |
1 files changed, 26 insertions, 4 deletions
@@ -380,16 +380,18 @@ //! # use iced::{Element, Task}; //! # pub struct Contacts; //! # impl Contacts { -//! # pub fn update(&mut self, message: Message) -> Task<Message> { unimplemented!() } +//! # pub fn update(&mut self, message: Message) -> Action { unimplemented!() } //! # pub fn view(&self) -> Element<Message> { unimplemented!() } //! # } //! # #[derive(Debug)] //! # pub enum Message {} +//! # pub enum Action { None, Run(Task<Message>), Chat(()) } //! # } //! # mod conversation { //! # use iced::{Element, Task}; //! # pub struct Conversation; //! # impl Conversation { +//! # pub fn new(contact: ()) -> (Self, Task<Message>) { unimplemented!() } //! # pub fn update(&mut self, message: Message) -> Task<Message> { unimplemented!() } //! # pub fn view(&self) -> Element<Message> { unimplemented!() } //! # } @@ -419,7 +421,19 @@ //! match message { //! Message::Contacts(message) => { //! if let Screen::Contacts(contacts) = &mut state.screen { -//! contacts.update(message).map(Message::Contacts) +//! let action = contacts.update(message); +//! +//! match action { +//! contacts::Action::None => Task::none(), +//! contacts::Action::Run(task) => task.map(Message::Contacts), +//! contacts::Action::Chat(contact) => { +//! let (conversation, task) = Conversation::new(contact); +//! +//! state.screen = Screen::Conversation(conversation); +//! +//! task.map(Message::Conversation) +//! } +//! } //! } else { //! Task::none() //! } @@ -442,8 +456,16 @@ //! } //! ``` //! -//! Functor methods like [`Task::map`], [`Element::map`], and [`Subscription::map`] make this -//! approach seamless. +//! The `update` method of a screen can return an `Action` enum that can be leveraged by the parent to +//! execute a task or transition to a completely different screen altogether. The variants of `Action` can +//! have associated data. For instance, in the example above, the `Conversation` screen is created when +//! `Contacts::update` returns an `Action::Chat` with the selected contact. +//! +//! Effectively, this approach lets you "tell a story" to connect different screens together in a type safe +//! way. +//! +//! Furthermore, functor methods like [`Task::map`], [`Element::map`], and [`Subscription::map`] make composition +//! seamless. #![doc( html_logo_url = "https://raw.githubusercontent.com/iced-rs/iced/bdf0430880f5c29443f5f0a0ae4895866dfef4c6/docs/logo.svg" )] |