Struct glib::Binding [−][src]
pub struct Binding(_);
Expand description
Binding is the representation of a binding between a property on a
Object instance (or source) and another property on another Object
instance (or target). Whenever the source property changes, the same
value is applied to the target property; for instance, the following
binding:
⚠️ The following code is in C ⚠️
g_object_bind_property (object1, "property-a",
object2, "property-b",
G_BINDING_DEFAULT);
will cause the property named “property-b” of object2 to be updated
every time [ObjectExtManual::set()][crate::prelude::ObjectExtManual::set()] or the specific accessor changes the value of
the property “property-a” of object1.
It is possible to create a bidirectional binding between two properties
of two Object instances, so that if either property changes, the
other is updated as well, for instance:
⚠️ The following code is in C ⚠️
g_object_bind_property (object1, "property-a",
object2, "property-b",
G_BINDING_BIDIRECTIONAL);
will keep the two properties in sync.
It is also possible to set a custom transformation function (in both directions, in case of a bidirectional binding) to apply a custom transformation from the source value to the target value before applying it; for instance, the following binding:
⚠️ The following code is in C ⚠️
g_object_bind_property_full (adjustment1, "value",
adjustment2, "value",
G_BINDING_BIDIRECTIONAL,
celsius_to_fahrenheit,
fahrenheit_to_celsius,
NULL, NULL);
will keep the “value” property of the two adjustments in sync; the
celsius_to_fahrenheit function will be called whenever the “value”
property of adjustment1 changes and will transform the current value
of the property before applying it to the “value” property of adjustment2.
Vice versa, the fahrenheit_to_celsius function will be called whenever
the “value” property of adjustment2 changes, and will transform the
current value of the property before applying it to the “value” property
of adjustment1.
Note that Binding does not resolve cycles by itself; a cycle like
object1:propertyA -> object2:propertyB
object2:propertyB -> object3:propertyC
object3:propertyC -> object1:propertyA
might lead to an infinite loop. The loop, in this particular case,
can be avoided if the objects emit the signal::Object::notify signal only
if the value has effectively been changed. A binding is implemented
using the signal::Object::notify signal, so it is susceptible to all the
various ways of blocking a signal emission, like g_signal_stop_emission()
or g_signal_handler_block().
A binding will be severed, and the resources it allocates freed, whenever
either one of the Object instances it refers to are finalized, or when
the Binding instance loses its last reference.
Bindings for languages with garbage collection can use
unbind() to explicitly release a binding between the source
and target properties, instead of relying on the last reference on the
binding, source, and target instances to drop.
Binding is available since GObject 2.26
Implements
Implementations
Retrieves the flags passed when constructing the Binding.
Returns
the BindingFlags used by the Binding
Flags to be used to control the Binding
Retrieves the name of the property of property::Binding::source used as the source
of the binding.
Returns
the name of the source property
The name of the property of property::Binding::source that should be used
as the source of the binding.
This should be in [canonical form][canonical-parameter-names] to get the best performance.
Retrieves the name of the property of property::Binding::target used as the target
of the binding.
Returns
the name of the target property
The name of the property of property::Binding::target that should be used
as the target of the binding.
This should be in [canonical form][canonical-parameter-names] to get the best performance.
Explicitly releases the binding between the source and the target
property expressed by self.
This function will release the reference that is being held on
the self instance if the binding is still bound; if you want to hold on
to the Binding instance after calling unbind(), you will need
to hold a reference to it.
Note however that this function does not take ownership of self, it
only unrefs the reference that was initially created by
[ObjectExtManual::bind_property()][crate::prelude::ObjectExtManual::bind_property()] and is owned by the binding.
Trait Implementations
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Returns the type identifier of Self.
Auto Trait Implementations
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T. Read more
Upcasts an object to a reference of its superclass or interface T. Read more
Tries to downcast to a subclass or interface implementor T. Read more
Tries to downcast to a reference of its subclass or interface implementor T. Read more
Tries to cast to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Casts to T unconditionally. Read more
Casts to &T unconditionally. Read more
Returns true if the object is an instance of (can be cast to) T.
pub fn set_property<'a, N, V>(&Self, N, V) -> Result<(), BoolError> where
N: Into<&'a str>,
V: ToValue, pub fn set_property_from_value<'a, N>(&Self, N, &Value) -> Result<(), BoolError> where
N: Into<&'a str>, Safety Read more
pub fn connect_notify<F>(&Self, Option<&str>, F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync, pub fn connect_notify_local<F>(&Self, Option<&str>, F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec), pub unsafe fn connect_notify_unsafe<F>(
&Self,
Option<&str>,
F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec), pub fn connect<'a, N, F>(
&Self,
N,
bool,
F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static, Same as connect but takes a SignalId instead of a signal name.
pub fn connect_local<'a, N, F>(
&Self,
N,
bool,
F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: Fn(&[Value]) -> Option<Value> + 'static, Same as connect_local but takes a SignalId instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&Self,
N,
bool,
F
) -> Result<SignalHandlerId, BoolError> where
N: Into<&'a str>,
F: Fn(&[Value]) -> Option<Value>, Same as connect_unsafe but takes a SignalId instead of a signal name.
Emit signal by signal id.
Emit signal with details by signal id.
Emit signal by it’s name.
pub fn bind_property<'a, O, N, M>(&'a Self, N, &'a O, M) -> BindingBuilder<'a> where
N: Into<&'a str>,
O: ObjectType,
M: Into<&'a str>, Same as emit but takes Value for the arguments.
Same as emit_by_name but takes Value for the arguments.
Returns a SendValue clone of self.
impl<'a, T, C> FromValueOptional<'a> for T where
C: ValueTypeChecker<Error = ValueTypeMismatchOrNoneError>,
T: FromValue<'a, Checker = C>,