#Disable Builder

Disable Builder is used to switch view to ControlState::Disabled. It's application-side configuration view state builder, not a method custom view authors need to override in View trait.

Currently exposed interface is:

pub trait DisableBuilder {
    fn disable<F>(self, f: F) -> Self
    where
        F: Fn() -> bool + 'static;
}

#Basic Writing

After importing DisableBuilder, all views implementing View can call .disable(...).

use flor::view::builder::DisableBuilder;
use flor_lys::button::button;

let save = button("Save").disable(|| true);

Closure returns true means disabled, returns false means normal. Fixed disable can directly write || true, but more common is reading state from signal.

#Reactive Disable

.disable(...) will create a reactive updater. After signal read in closure changes, framework will recalculate disable state.

use flor::signal::{create_signal, Read, Write};
use flor::view::builder::DisableBuilder;
use flor_lys::button::button;

let saving = create_signal(false);

let save = button("Save")
    .disable(move || saving.get());

// Disable button when starting save.
saving.set(true);

When need to combine multiple conditions, directly write business judgment in closure:

use flor::signal::{create_signal, Read};
use flor::view::builder::DisableBuilder;
use flor_lys::button::button;

let saving = create_signal(false);
let form_valid = create_signal(false);

let submit = button("Submit")
    .disable(move || saving.get() || !form_valid.get());

#Mechanism Explanation

.disable(...) internally will:

1. Read current view's ViewId.
2. Use create_updater_with_id to create an updater.
3. Write ViewState.disable when updater changes.
4. Attach effect id to current ViewId's pending effect list, view creation process will activate it.

Disable state participates in ControlState calculation, and has highest priority: Disabled > Active > Focus > Hover > Normal. View authors read ControlState::Disabled in on_draw, on_measure or event handling, decide visual and interaction behavior in disabled state.

Disable doesn't automatically remove focus table entry, also doesn't automatically cancel current focus. When need runtime change focus capability, use ViewId's focus API.