Class PropertyAction
GPropertyAction
is a way to get a Action
with a state value
reflecting and controlling the value of a GObject
property.
The state of the action will correspond to the value of the property.
Changing it will change the property (assuming the requested value
matches the requirements as specified in the GObject.ParamSpec
).
Only the most common types are presently supported. Booleans are mapped to booleans, strings to strings, signed/unsigned integers to int32/uint32 and floats and doubles to doubles.
If the property is an enum then the state will be string-typed and
conversion will automatically be performed between the enum value and
‘nick’ string as per the GObject.EnumValue
table.
Flags types are not currently supported.
Properties of object types, boxed types and pointer types are not supported and probably never will be.
Properties of GLib.Variant
types are not currently supported.
If the property is boolean-valued then the action will have a NULL
parameter type, and activating the action (with no parameter) will
toggle the value of the property.
In all other cases, the parameter type will correspond to the type of the property.
The general idea here is to reduce the number of locations where a
particular piece of state is kept (and therefore has to be synchronised
between). GPropertyAction
does not have a separate state that is kept
in sync with the property value — its state is the property value.
For example, it might be useful to create a Action
corresponding
to the visible-child-name
property of a GtkStack
so that the current page can be switched from a menu. The active radio
indication in the menu is then directly determined from the active page of
the GtkStack
.
An anti-example would be binding the active-id
property on a
GtkComboBox
. This is
because the state of the combo box itself is probably uninteresting and is
actually being used to control something else.
Another anti-example would be to bind to the visible-child-name
property of a GtkStack
if
this value is actually stored in Settings
. In that case, the
real source of the value is* Settings
. If you want
a Action
to control a setting stored in Settings
,
see Settings.createAction(java.lang.String)
instead, and possibly combine its
use with Settings.bind(java.lang.String, org.gnome.gobject.GObject, java.lang.String, java.util.Set<org.gnome.gio.SettingsBindFlags>)
.
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Nested Class Summary
Modifier and TypeClassDescriptionstatic class
PropertyAction.Builder<B extends PropertyAction.Builder<B>>
Inner class implementing a builder pattern to construct a GObject with properties.Nested classes/interfaces inherited from class org.gnome.gobject.GObject
GObject.NotifyCallback, GObject.ObjectClass
Nested classes/interfaces inherited from interface org.gnome.gio.Action
Action.ActionImpl, Action.ActionInterface
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Constructor Summary
ConstructorDescriptionPropertyAction
(MemorySegment address) Create a PropertyAction proxy instance for the provided memory address.PropertyAction
(String name, GObject object, String propertyName) Creates aGAction
corresponding to the value of propertypropertyName
onobject
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Method Summary
Modifier and TypeMethodDescriptionprotected PropertyAction
asParent()
Returns this instance as if it were its parent type.static PropertyAction.Builder
<? extends PropertyAction.Builder> builder()
APropertyAction.Builder
object constructs aPropertyAction
with the specified properties.static Type
getType()
Get the GType of the PropertyAction classMethods inherited from class org.gnome.gobject.GObject
addToggleRef, addWeakPointer, bindProperty, bindProperty, bindProperty, bindPropertyFull, bindPropertyFull, bindPropertyWithClosures, bindPropertyWithClosures, compatControl, connect, connect, connect, constructed, disconnect, dispatchPropertiesChanged, dispose, dupData, dupQdata, emit, emitNotify, finalize_, forceFloating, freezeNotify, get, getData, getMemoryLayout, getProperty, getProperty, getProperty, getQdata, getv, interfaceFindProperty, interfaceInstallProperty, interfaceListProperties, isFloating, newInstance, newInstance, newInstance, newInstance, newv, notify_, notify_, notifyByPspec, onNotify, ref, refSink, removeToggleRef, removeWeakPointer, replaceData, replaceQdata, runDispose, set, setData, setDataFull, setProperty, setProperty, setProperty, setQdata, setQdataFull, setv, stealData, stealQdata, takeRef, thawNotify, unref, watchClosure, weakRef, weakUnref, withProperties
Methods inherited from class org.gnome.gobject.TypeInstance
callParent, callParent, getPrivate, readGClass, writeGClass
Methods inherited from class io.github.jwharm.javagi.base.ProxyInstance
equals, handle, hashCode
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.gnome.gio.Action
activate, changeState, getEnabled, getName, getParameterType, getState, getStateHint, getStateType
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Constructor Details
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PropertyAction
Create a PropertyAction proxy instance for the provided memory address.- Parameters:
address
- the memory address of the native object
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PropertyAction
Creates aGAction
corresponding to the value of propertypropertyName
onobject
.The property must be existent and readable and writable (and not construct-only).
This function takes a reference on
object
and doesn't release it until the action is destroyed.- Parameters:
name
- the name of the action to createobject
- the object that has the property to wrappropertyName
- the name of the property
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Method Details
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getType
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asParent
Returns this instance as if it were its parent type. This is mostly synonymous to the Javasuper
keyword, but will set the native typeclass function pointers to the parent type. When overriding a native virtual method in Java, "chaining up" withsuper.methodName()
doesn't work, because it invokes the overridden function pointer again. To chain up, callasParent().methodName()
. This will call the native function pointer of this virtual method in the typeclass of the parent type. -
builder
APropertyAction.Builder
object constructs aPropertyAction
with the specified properties. Use the variousset...()
methods to set properties, and finish construction withPropertyAction.Builder.build()
.
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