Struct druid::widget::ViewSwitcher

pub struct ViewSwitcher<T, U> { /* fields omitted */ }

Implementations

impl<T: Data, U: PartialEq> ViewSwitcher<T, U>

pub fn new(
    child_picker: impl Fn(&T, &Env) -> U + 'static,
    child_builder: impl Fn(&U, &T, &Env) -> Box<dyn Widget<T>> + 'static
) -> Self

Create a new view switcher.

The child_picker closure is called every time the application data changes. If the value it returns is the same as the one it returned during the previous data change, nothing happens. If it returns a different value, then the child_builder closure is called with the new value.

The child_builder closure creates a new child widget based on the value passed to it.

Trait Implementations

impl<T: Data, U: PartialEq> Widget<T> for ViewSwitcher<T, U>

fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut T, env: &Env)

Handle an event.

fn lifecycle(
    &mut self,
    ctx: &mut LifeCycleCtx,
    event: &LifeCycle,
    data: &T,
    env: &Env
)

Handle a life cycle notification.

fn update(&mut self, ctx: &mut UpdateCtx, _old_data: &T, data: &T, env: &Env)

Handle a change of data.

fn layout(
    &mut self,
    ctx: &mut LayoutCtx,
    bc: &BoxConstraints,
    data: &T,
    env: &Env
) -> Size

Compute layout.

fn paint(&mut self, ctx: &mut PaintCtx, data: &T, env: &Env)

Paint the widget appearance.