[−][src]Trait orbtk_api::widget_base::State

pub trait State: AsAny {
    fn init(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>) { ... }

    fn cleanup(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>) { ... }

    fn update(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>) { ... }

    fn update_post_layout(
        &mut self, 
        _registry: &mut Registry, 
        _ctx: &mut Context<'_>
    ) { ... }
}

Used to define a state of a widget.

The state holds the logic of a widget which makes it interactive. The state of a widget is made of a struct which implements this trait with its fields and its methods. A state of a widget is represented by the current values of its properties. Each state has to implement this trait. Each state has to derive or implement the Default and the AsAny traits. A state is operating on the properties (components) of the widget, its parent or children, or the state's fields. It is not mandatory to have a state for a widget (in this case it will be static).

Example

use orbtk::prelude::*;

#[derive(Default, AsAny)]
struct MyState {
    count: usize
}

impl State for MyState {
    fn init(&mut self, _registry: &mut Registry, _ctx: &mut Context) {
        self.count = 42;
        println!("MyState initialized.");
    }

    fn update(&mut self, _registry: &mut Registry, _ctx: &mut Context) {
        self.count += 1;
        println("MyState updated.");
    }

    fn update_post_layout(&mut self, _registry: &mut Registry, _ctx: &mut Context) {
        println("MyState updated after layout is calculated.");
    }
}

widget!(MyWidget<MyState>)

Provided methods

fn init(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>)

Init is used for setting up the initial state of a widget, setting up fields to starting values and registering service(s). It is called after the widget is created.

Arguments

  • _registry: Provides access to the global Service Registry.
  • _ctx: Represents the context of the current widget.Lets you manipulate the widget tree.

fn cleanup(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>)

Used to cleanup the state and is called after window close is requested.

Arguments

  • _registry: Provides access to the global Service Registry.
  • _ctx: Represents the context of the current widget.Allows manipulation of the widget tree.

fn update(&mut self, _registry: &mut Registry, _ctx: &mut Context<'_>)

Updates the state of a widget before layout is calculated for the given context when the widget becomes "dirty", (e.g.: a property of a widget is changed or an event is fired)

Arguments

  • _registry: Provides access to the global Service Registry.
  • _ctx: Represents the context of the current widget.Allows manipulation of the widget tree.

fn update_post_layout(
    &mut self,
    _registry: &mut Registry,
    _ctx: &mut Context<'_>
)

Updates the state after layout is calculated and before rendering for the given context when the widget becomes "dirty", (e.g.: a property of a widget is changed, or an event is fired)

Arguments

  • _registry: Provides access to the global Service Registry.
  • _ctx: Represents the context of the current widget.Allows manipulation of the widget tree.
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Implementors

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