Struct slint_interpreter::Weak

pub struct Weak<T>
where T: ComponentHandle,
{ /* private fields */ }
Expand description

Struct that’s used to hold weak references of a Slint component

In order to create a Weak, you should use ComponentHandle::as_weak.

Strong references should not be captured by the functions given to a lambda, as this would produce a reference loop and leak the component. Instead, the callback function should capture a weak component.

The Weak component also implement Send and can be send to another thread. but the upgrade function will only return a valid component from the same thread as the one it has been created from. This is useful to use with invoke_from_event_loop() or Self::upgrade_in_event_loop().

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impl<T> Weak<T>
where T: ComponentHandle,

pub fn upgrade(&self) -> Option<T>
where T: ComponentHandle,

Returns a new strongly referenced component if some other instance still holds a strong reference. Otherwise, returns None.

This also returns None if the current thread is not the thread that created the component

pub fn unwrap(&self) -> T

Convenience function that returns a new strongly referenced component if some other instance still holds a strong reference and the current thread is the thread that created this component. Otherwise, this function panics.

pub fn upgrade_in_event_loop( &self, func: impl FnOnce(T) + Send + 'static, ) -> Result<(), EventLoopError>
where T: 'static,

Convenience function that combines invoke_from_event_loop() with Self::upgrade()

The given functor will be added to an internal queue and will wake the event loop. On the next iteration of the event loop, the functor will be executed with a T as an argument.

If the component was dropped because there are no more strong reference to the component, the functor will not be called.

§Example
slint::slint! { export component MyApp inherits Window { in property <int> foo; /* ... */ } }
let handle = MyApp::new().unwrap();
let handle_weak = handle.as_weak();
let thread = std::thread::spawn(move || {
    // ... Do some computation in the thread
    let foo = 42;
    // now forward the data to the main thread using upgrade_in_event_loop
    handle_weak.upgrade_in_event_loop(move |handle| handle.set_foo(foo));
});
handle.run().unwrap();

Trait Implementations§

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impl<T> Clone for Weak<T>
where T: ComponentHandle,

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fn clone(&self) -> Weak<T>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T> Default for Weak<T>
where T: ComponentHandle,

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fn default() -> Weak<T>

Returns the “default value” for a type. Read more
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impl<T> Send for Weak<T>
where T: ComponentHandle,

Auto Trait Implementations§

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impl<T> Freeze for Weak<T>

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impl<T> RefUnwindSafe for Weak<T>

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impl<T> !Sync for Weak<T>

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impl<T> Unpin for Weak<T>

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impl<T> UnwindSafe for Weak<T>

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> Downcast for T
where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> NoneValue for T
where T: Default,

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type NoneType = T

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fn null_value() -> T

The none-equivalent value.
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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<R, P> ReadPrimitive<R> for P
where R: Read + ReadEndian<P>, P: Default,

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fn read_from_little_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_little_endian().
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fn read_from_big_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_big_endian().
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fn read_from_native_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_native_endian().
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impl<T> Same for T

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type Output = T

Should always be Self
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where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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type Error = Infallible

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