Support async actions in iced_winit

src/lib.rs

@@ -4,21 +4,23 @@ mod platform;
 
 pub use platform::*;
 
-pub trait Application {
-    type Message: std::fmt::Debug;
+pub trait Application: Sized {
+    type Message: std::fmt::Debug + Send;
+
+    fn new() -> (Self, Command<Self::Message>);
 
     fn title(&self) -> String;
 
-    fn update(&mut self, message: Self::Message);
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
 
     fn view(&mut self) -> Element<Self::Message>;
 
-    fn run(self)
+    fn run()
     where
         Self: 'static + Sized,
     {
         #[cfg(not(target_arch = "wasm32"))]
-        iced_winit::Application::run(Instance(self));
+        <Instance<Self> as iced_winit::Application>::run();
 
         #[cfg(target_arch = "wasm32")]
         iced_web::Application::run(Instance(self));
@@ -35,12 +37,18 @@ where
     type Renderer = Renderer;
     type Message = A::Message;
 
+    fn new() -> (Self, Command<A::Message>) {
+        let (app, command) = A::new();
+
+        (Instance(app), command)
+    }
+
     fn title(&self) -> String {
         self.0.title()
     }
 
-    fn update(&mut self, message: Self::Message) {
-        self.0.update(message);
+    fn update(&mut self, message: Self::Message) -> Command<Self::Message> {
+        self.0.update(message)
     }
 
     fn view(&mut self) -> Element<Self::Message> {

src/winit.rs

@@ -2,8 +2,8 @@ pub use iced_wgpu::{Primitive, Renderer};
 
 pub use iced_winit::{
     button, scrollable, slider, text, text_input, winit, Align, Background,
-    Checkbox, Color, Font, Image, Length, Radio, Scrollable, Slider, Text,
-    TextInput,
+    Checkbox, Color, Command, Font, Image, Length, Radio, Scrollable, Slider,
+    Text, TextInput,
 };
 
 pub type Element<'a, Message> = iced_winit::Element<'a, Message, Renderer>;