Struct State 

pub struct State<'s, T: 'static> { /* private fields */ }

A guard over one use_state slot.

Derefs to T, so *count += 1 works. The value lives in the store, so nothing is written back on drop; the only thing drop does is request a repaint if the value was mutably dereferenced.

Implementations

impl<'s, T: 'static> State<'s, T>

pub fn into_handle(self) -> Handle<'s, T>

Consume the guard and return a Copy Handle to the same slot.

This releases the guard’s borrow. There is deliberately no handle(&self): using a Handle while the guard is alive would double-borrow the same RefCell and panic.

pub fn bind(&mut self) -> &mut T

Hand &mut T to a widget that writes into it directly.

Unlike &mut *state this does not mark the state dirty, so a bound widget does not ask for a repaint on every single frame. That is safe because the widget only changes the value in response to input, and input makes egui repaint anyway. This is what the bind prop of TextEdit, Checkbox, Slider and ComboBox expects.

pub fn update_later(&self, f: impl FnOnce(&mut T) + 'static)

Queue a write for the end of the pass and request a repaint.

This is the way out of “the loop borrows the state, so the handler inside it cannot”: todos.update_later(move |t| t.remove(i)). The closure is 'static, so captures need move.

Calling this while the guard is alive is fine: the write happens long after the guard is gone.

Trait Implementations

impl<T: 'static> Deref for State<'_, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T: 'static> DerefMut for State<'_, T>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T: 'static> Drop for State<'_, T>

fn drop(&mut self)

Executes the destructor for this type.