[−][src]Trait iced::Application
An interactive cross-platform application.
This trait is the main entrypoint of Iced. Once implemented, you can run
your GUI application by simply calling run
.
- On native platforms, it will run in its own window.
- On the web, it will take control of the
<title>
and the<body>
of the document.
An Application
can execute asynchronous actions by returning a
Command
in some of its methods. If
you do not intend to perform any background work in your program, the
Sandbox
trait offers a simplified interface.
When using an Application
with the debug
feature enabled, a debug view
can be toggled by pressing F12
.
Examples
The repository has a bunch of examples that use the Application
trait:
clock
, an application that uses theCanvas
widget to draw a clock and its hands to display the current time.download_progress
, a basic application that asynchronously downloads a dummy file of 100 MB and tracks the download progress.events
, a log of native events displayed using a conditionalSubscription
.pokedex
, an application that displays a random Pokédex entry (sprite included!) by using the PokéAPI.solar_system
, an animated solar system drawn using theCanvas
widget and showcasing how to compose different transforms.stopwatch
, a watch with start/stop and reset buttons showcasing how to listen to time.todos
, a todos tracker inspired by TodoMVC.
A simple "Hello, world!"
If you just want to get started, here is a simple Application
that
says "Hello, world!":
use iced::{executor, Application, Command, Element, Settings, Text}; pub fn main() { Hello::run(Settings::default()) } struct Hello; impl Application for Hello { type Executor = executor::Null; type Message = (); type Flags = (); fn new(_flags: ()) -> (Hello, Command<Self::Message>) { (Hello, Command::none()) } fn title(&self) -> String { String::from("A cool application") } fn update(&mut self, _message: Self::Message) -> Command<Self::Message> { Command::none() } fn view(&mut self) -> Element<Self::Message> { Text::new("Hello, world!").into() } }
Associated Types
type Executor: Executor
The Executor
that will run commands and subscriptions.
The default executor can be a good starting point!
type Message: Debug + Send
The type of messages your Application
will produce.
type Flags
The data needed to initialize your Application
.
Required methods
fn new(flags: Self::Flags) -> (Self, Command<Self::Message>)
Initializes the Application
with the flags provided to
run
as part of the Settings
.
Here is where you should return the initial state of your app.
Additionally, you can return a Command
if you
need to perform some async action in the background on startup. This is
useful if you want to load state from a file, perform an initial HTTP
request, etc.
fn title(&self) -> String
Returns the current title of the Application
.
This title can be dynamic! The runtime will automatically update the title of your application when necessary.
fn update(&mut self, message: Self::Message) -> Command<Self::Message>
Handles a message and updates the state of the Application
.
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 Command
returned will be executed immediately in the background.
fn view(&mut self) -> Element<'_, Self::Message>
Returns the widgets to display in the Application
.
These widgets can produce messages based on user interaction.
Provided methods
fn subscription(&self) -> Subscription<Self::Message>
Returns the event Subscription
for the current state of the
application.
A Subscription
will be kept alive as long as you keep returning it,
and the messages produced will be handled by
update
.
By default, this method returns an empty Subscription
.
fn mode(&self) -> Mode
Returns the current Application
mode.
The runtime will automatically transition your application if a new mode is returned.
Currently, the mode only has an effect in native platforms.
By default, an application will run in windowed mode.
fn background_color(&self) -> Color
Returns the background color of the Application
.
By default, it returns Color::WHITE
.
fn scale_factor(&self) -> f64
Returns the scale factor of the Application
.
It can be used to dynamically control the size of the UI at runtime (i.e. zooming).
For instance, a scale factor of 2.0
will make widgets twice as big,
while a scale factor of 0.5
will shrink them to half their size.
By default, it returns 1.0
.
fn run(settings: Settings<Self::Flags>) where
Self: 'static,
Self: 'static,
Runs the Application
.
On native platforms, this method will take control of the current thread and will NOT return.
It should probably be that last thing you call in your main
function.
Implementors
impl<T> Application for T where
T: Sandbox,
[src]
T: Sandbox,