Package ch.bailu.gtk.gobject

Klasse Binding

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.type.PropertyHolder
ch.bailu.gtk.gobject.Binding
Alle implementierten Schnittstellen:
PointerInterface
public class Binding extends PropertyHolder
`GObject` instance (or source) and another property on another `GObject`
instance (or target).

Whenever the source property changes, the same value is applied to the
target property; for instance, the following binding:

```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 [method@GObject.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 `GObject` instances, so that if either property changes, the
other is updated as well, for instance:

```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:

```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 #GBinding 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 `GObject::notify` signal only
if the value has effectively been changed. A binding is implemented
using the `GObject::notify` signal, so it is susceptible to all the
various ways of blocking a signal emission, like [func@GObject.signal_stop_emission]
or [func@GObject.signal_handler_block].

A binding will be severed, and the resources it allocates freed, whenever
either one of the `GObject` instances it refers to are finalized, or when
the #GBinding instance loses its last reference.

Bindings for languages with garbage collection can use
[method@GObject.Binding.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.

https://docs.gtk.org/gobject/class.Binding.html

  • Konstruktordetails

  • Methodendetails

    • getClassHandler

      public static ClassHandler getClassHandler()

    • dupSource

      public Object dupSource()
      Retrieves the #GObject instance used as the source of the binding.

      A #GBinding can outlive the source #GObject as the binding does not hold a
      strong reference to the source. If the source is destroyed before the
      binding then this function will return %NULL.
      Gibt zurück:
      the source #GObject, or %NULL if the source does not exist any more.

    • dupTarget

      public Object dupTarget()
      Retrieves the #GObject instance used as the target of the binding.

      A #GBinding can outlive the target #GObject as the binding does not hold a
      strong reference to the target. If the target is destroyed before the
      binding then this function will return %NULL.
      Gibt zurück:
      the target #GObject, or %NULL if the target does not exist any more.

    • getFlags

      public int getFlags()
      Retrieves the flags passed when constructing the #GBinding.
      Gibt zurück:
      the #GBindingFlags used by the #GBinding

    • getSource

      @Deprecated public Object getSource()
      Veraltet.
      Retrieves the #GObject instance used as the source of the binding.

      A #GBinding can outlive the source #GObject as the binding does not hold a
      strong reference to the source. If the source is destroyed before the
      binding then this function will return %NULL.

      Use g_binding_dup_source() if the source or binding are used from different
      threads as otherwise the pointer returned from this function might become
      invalid if the source is finalized from another thread in the meantime.
      Gibt zurück:
      the source #GObject, or %NULL if the source does not exist any more.

    • getSourceProperty

      public Str getSourceProperty()
      Retrieves the name of the property of #GBinding:source used as the source
      of the binding.
      Gibt zurück:
      the name of the source property

    • getTarget

      @Deprecated public Object getTarget()
      Veraltet.
      Retrieves the #GObject instance used as the target of the binding.

      A #GBinding can outlive the target #GObject as the binding does not hold a
      strong reference to the target. If the target is destroyed before the
      binding then this function will return %NULL.

      Use g_binding_dup_target() if the target or binding are used from different
      threads as otherwise the pointer returned from this function might become
      invalid if the target is finalized from another thread in the meantime.
      Gibt zurück:
      the target #GObject, or %NULL if the target does not exist any more.

    • getTargetProperty

      public Str getTargetProperty()
      Retrieves the name of the property of #GBinding:target used as the target
      of the binding.
      Gibt zurück:
      the name of the target property

    • unbind

      public void unbind()
      Explicitly releases the binding between the source and the target
      property expressed by @binding.

      This function will release the reference that is being held on
      the @binding instance if the binding is still bound; if you want to hold on
      to the #GBinding instance after calling g_binding_unbind(), you will need
      to hold a reference to it.

      Note however that this function does not take ownership of @binding, it
      only unrefs the reference that was initially created by
      g_object_bind_property() and is owned by the binding.

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()