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mx.binding.utils 

ChangeWatcher  - AS3 Flex

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adobe.utils
air.desktop
air.net
air.update
air.update.events
coldfusion.air
coldfusion.air.errors
coldfusion.air.events
coldfusion.service
coldfusion.service.events
coldfusion.service.mxml
com.adobe.acm.solutions.authoring.domain.extensions
com.adobe.acm.solutions.ccr.domain.extensions
com.adobe.consulting.pst.vo
com.adobe.dct.component
com.adobe.dct.component.datadictionary
com.adobe.dct.component.datadictionaryElement
com.adobe.dct.component.dataElementsPanel
com.adobe.dct.component.toolbars
com.adobe.dct.event
com.adobe.dct.exp
com.adobe.dct.model
com.adobe.dct.service
com.adobe.dct.service.provider
com.adobe.dct.transfer
com.adobe.dct.util
com.adobe.dct.view
com.adobe.ep.taskmanagement.domain
com.adobe.ep.taskmanagement.event
com.adobe.ep.taskmanagement.filter
com.adobe.ep.taskmanagement.services
com.adobe.ep.taskmanagement.util
com.adobe.ep.ux.attachmentlist.component
com.adobe.ep.ux.attachmentlist.domain
com.adobe.ep.ux.attachmentlist.domain.events
com.adobe.ep.ux.attachmentlist.domain.renderers
com.adobe.ep.ux.attachmentlist.skin
com.adobe.ep.ux.attachmentlist.skin.renderers
com.adobe.ep.ux.content.event
com.adobe.ep.ux.content.factory
com.adobe.ep.ux.content.handlers
com.adobe.ep.ux.content.managers
com.adobe.ep.ux.content.model.asset
com.adobe.ep.ux.content.model.preview
com.adobe.ep.ux.content.model.relation
com.adobe.ep.ux.content.model.search
com.adobe.ep.ux.content.model.toolbar
com.adobe.ep.ux.content.search
com.adobe.ep.ux.content.services
com.adobe.ep.ux.content.services.load
com.adobe.ep.ux.content.services.permissions
com.adobe.ep.ux.content.services.preview
com.adobe.ep.ux.content.services.providers
com.adobe.ep.ux.content.services.query
com.adobe.ep.ux.content.services.relationships
com.adobe.ep.ux.content.services.search.lccontent
com.adobe.ep.ux.content.services.version
com.adobe.ep.ux.content.view
com.adobe.ep.ux.content.view.components.activate
com.adobe.ep.ux.content.view.components.grid
com.adobe.ep.ux.content.view.components.grid.hover
com.adobe.ep.ux.content.view.components.grid.hover.component
com.adobe.ep.ux.content.view.components.grid.renderers
com.adobe.ep.ux.content.view.components.relationships
com.adobe.ep.ux.content.view.components.review
com.adobe.ep.ux.content.view.components.search.renderers
com.adobe.ep.ux.content.view.components.searchpod
com.adobe.ep.ux.content.view.components.toolbar
com.adobe.ep.ux.content.view.components.toolbar.controlRenderers
com.adobe.ep.ux.content.view.components.version
com.adobe.ep.ux.documentsubmit.component
com.adobe.ep.ux.documentsubmit.domain
com.adobe.ep.ux.documentsubmit.skin
com.adobe.ep.ux.taskaction.component
com.adobe.ep.ux.taskaction.domain
com.adobe.ep.ux.taskaction.domain.events
com.adobe.ep.ux.taskaction.skin
com.adobe.ep.ux.taskdetails.component
com.adobe.ep.ux.taskdetails.domain
com.adobe.ep.ux.taskdetails.skin
com.adobe.ep.ux.tasklist.component
com.adobe.ep.ux.tasklist.domain
com.adobe.ep.ux.tasklist.skin
com.adobe.ep.ux.webdocumentviewer.domain
com.adobe.exm.expression
com.adobe.exm.expression.error
com.adobe.exm.expression.event
com.adobe.exm.expression.impl
com.adobe.fiber.runtime.lib
com.adobe.fiber.services
com.adobe.fiber.services.wrapper
com.adobe.fiber.styles
com.adobe.fiber.util
com.adobe.fiber.valueobjects
com.adobe.gravity.binding
com.adobe.gravity.context
com.adobe.gravity.flex.bundleloader
com.adobe.gravity.flex.progress
com.adobe.gravity.flex.serviceloader
com.adobe.gravity.framework
com.adobe.gravity.init
com.adobe.gravity.service.bundleloader
com.adobe.gravity.service.logging
com.adobe.gravity.service.manifest
com.adobe.gravity.service.progress
com.adobe.gravity.tracker
com.adobe.gravity.ui
com.adobe.gravity.utility
com.adobe.gravity.utility.async
com.adobe.gravity.utility.error
com.adobe.gravity.utility.events
com.adobe.gravity.utility.factory
com.adobe.gravity.utility.flex.async
com.adobe.gravity.utility.logging
com.adobe.gravity.utility.message
com.adobe.gravity.utility.sequence
com.adobe.gravity.utility.url
com.adobe.guides.control
com.adobe.guides.domain
com.adobe.guides.i18n
com.adobe.guides.spark.components.skins
com.adobe.guides.spark.components.skins.mx
com.adobe.guides.spark.headers.components
com.adobe.guides.spark.headers.skins
com.adobe.guides.spark.layouts.components
com.adobe.guides.spark.layouts.skins
com.adobe.guides.spark.navigators.components
com.adobe.guides.spark.navigators.renderers
com.adobe.guides.spark.navigators.skins
com.adobe.guides.spark.util
com.adobe.guides.spark.wrappers.components
com.adobe.guides.spark.wrappers.skins
com.adobe.guides.submit
com.adobe.icc.dc.domain
com.adobe.icc.dc.domain.factory
com.adobe.icc.editors.events
com.adobe.icc.editors.handlers
com.adobe.icc.editors.managers
com.adobe.icc.editors.model
com.adobe.icc.editors.model.config
com.adobe.icc.editors.model.el
com.adobe.icc.editors.model.el.operands
com.adobe.icc.editors.model.el.operators
com.adobe.icc.enum
com.adobe.icc.external.dc
com.adobe.icc.obj
com.adobe.icc.services
com.adobe.icc.services.category
com.adobe.icc.services.config
com.adobe.icc.services.download
com.adobe.icc.services.export
com.adobe.icc.services.external
com.adobe.icc.services.formbridge
com.adobe.icc.services.fragmentlayout
com.adobe.icc.services.layout
com.adobe.icc.services.letter
com.adobe.icc.services.locator
com.adobe.icc.services.module
com.adobe.icc.services.render
com.adobe.icc.services.submit
com.adobe.icc.services.user
com.adobe.icc.token
com.adobe.icc.vo
com.adobe.icc.vo.render
com.adobe.icomm.assetplacement.controller
com.adobe.icomm.assetplacement.controller.utils
com.adobe.icomm.assetplacement.data
com.adobe.icomm.assetplacement.model
com.adobe.livecycle.assetmanager.client
com.adobe.livecycle.assetmanager.client.event
com.adobe.livecycle.assetmanager.client.handler
com.adobe.livecycle.assetmanager.client.managers
com.adobe.livecycle.assetmanager.client.model
com.adobe.livecycle.assetmanager.client.model.cms
com.adobe.livecycle.assetmanager.client.service
com.adobe.livecycle.assetmanager.client.service.search
com.adobe.livecycle.assetmanager.client.service.search.cms
com.adobe.livecycle.assetmanager.client.utils
com.adobe.livecycle.content
com.adobe.livecycle.rca.model
com.adobe.livecycle.rca.model.constant
com.adobe.livecycle.rca.model.document
com.adobe.livecycle.rca.model.participant
com.adobe.livecycle.rca.model.reminder
com.adobe.livecycle.rca.model.stage
com.adobe.livecycle.rca.service
com.adobe.livecycle.rca.service.core
com.adobe.livecycle.rca.service.core.delegate
com.adobe.livecycle.rca.service.process
com.adobe.livecycle.rca.service.process.delegate
com.adobe.livecycle.rca.token
com.adobe.livecycle.ria.security.api
com.adobe.livecycle.ria.security.service
com.adobe.mosaic.layouts
com.adobe.mosaic.layouts.dragAndDrop
com.adobe.mosaic.layouts.interfaces
com.adobe.mosaic.mxml
com.adobe.mosaic.om.constants
com.adobe.mosaic.om.events
com.adobe.mosaic.om.impl
com.adobe.mosaic.om.interfaces
com.adobe.mosaic.skinning
com.adobe.mosaic.sparklib.editors
com.adobe.mosaic.sparklib.optionMenu
com.adobe.mosaic.sparklib.scrollableMenu
com.adobe.mosaic.sparklib.scrollableMenu.skins
com.adobe.mosaic.sparklib.tabLayout
com.adobe.mosaic.sparklib.tabLayout.events
com.adobe.mosaic.sparklib.tabLayout.layouts
com.adobe.mosaic.sparklib.tabLayout.skins
com.adobe.mosaic.sparklib.text
com.adobe.mosaic.sparklib.util
com.adobe.solutions.acm.authoring.presentation
com.adobe.solutions.acm.authoring.presentation.actionbar
com.adobe.solutions.acm.authoring.presentation.common
com.adobe.solutions.acm.authoring.presentation.events
com.adobe.solutions.acm.authoring.presentation.fragment
com.adobe.solutions.acm.authoring.presentation.letter
com.adobe.solutions.acm.authoring.presentation.letter.data
com.adobe.solutions.acm.authoring.presentation.preview
com.adobe.solutions.acm.authoring.presentation.rte
com.adobe.solutions.acm.ccr.presentation
com.adobe.solutions.acm.ccr.presentation.contentcapture
com.adobe.solutions.acm.ccr.presentation.contentcapture.events
com.adobe.solutions.acm.ccr.presentation.contentcapture.preview
com.adobe.solutions.acm.ccr.presentation.datacapture
com.adobe.solutions.acm.ccr.presentation.datacapture.renderers
com.adobe.solutions.acm.ccr.presentation.pdf
com.adobe.solutions.exm
com.adobe.solutions.exm.authoring
com.adobe.solutions.exm.authoring.components.controls
com.adobe.solutions.exm.authoring.components.toolbars
com.adobe.solutions.exm.authoring.domain
com.adobe.solutions.exm.authoring.domain.expression
com.adobe.solutions.exm.authoring.domain.impl
com.adobe.solutions.exm.authoring.domain.method
com.adobe.solutions.exm.authoring.domain.variable
com.adobe.solutions.exm.authoring.enum
com.adobe.solutions.exm.authoring.events
com.adobe.solutions.exm.authoring.model
com.adobe.solutions.exm.authoring.renderer
com.adobe.solutions.exm.authoring.view
com.adobe.solutions.exm.expression
com.adobe.solutions.exm.impl
com.adobe.solutions.exm.impl.method
com.adobe.solutions.exm.method
com.adobe.solutions.exm.mock
com.adobe.solutions.exm.mock.method
com.adobe.solutions.exm.runtime
com.adobe.solutions.exm.runtime.impl
com.adobe.solutions.exm.variable
com.adobe.solutions.prm.constant
com.adobe.solutions.prm.domain
com.adobe.solutions.prm.domain.factory
com.adobe.solutions.prm.domain.impl
com.adobe.solutions.prm.domain.manager
com.adobe.solutions.prm.presentation.asset
com.adobe.solutions.prm.presentation.constant
com.adobe.solutions.prm.presentation.document
com.adobe.solutions.prm.presentation.event
com.adobe.solutions.prm.presentation.file
com.adobe.solutions.prm.presentation.project
com.adobe.solutions.prm.presentation.team
com.adobe.solutions.prm.presentation.util
com.adobe.solutions.prm.service
com.adobe.solutions.prm.services.impl
com.adobe.solutions.prm.vo
com.adobe.solutions.rca.constant
com.adobe.solutions.rca.domain
com.adobe.solutions.rca.domain.common
com.adobe.solutions.rca.domain.factory
com.adobe.solutions.rca.domain.impl
com.adobe.solutions.rca.domain.impl.manager
com.adobe.solutions.rca.domain.manager
com.adobe.solutions.rca.presentation
com.adobe.solutions.rca.presentation.comment
com.adobe.solutions.rca.presentation.constant
com.adobe.solutions.rca.presentation.event
com.adobe.solutions.rca.presentation.gantt
com.adobe.solutions.rca.presentation.gantt.ruler
com.adobe.solutions.rca.presentation.template
com.adobe.solutions.rca.presentation.template.audit
com.adobe.solutions.rca.presentation.template.definition
com.adobe.solutions.rca.presentation.template.documents
com.adobe.solutions.rca.presentation.template.stages
com.adobe.solutions.rca.presentation.util
com.adobe.solutions.rca.service
com.adobe.solutions.rca.services.impl
com.adobe.solutions.rca.vo
com.adobe.solutions.rca.vo.um
com.adobe.viewsource
fl.accessibility
fl.containers
fl.controls
fl.controls.dataGridClasses
fl.controls.listClasses
fl.controls.progressBarClasses
fl.core
fl.data
fl.display
fl.events
fl.ik
fl.lang
fl.livepreview
fl.managers
fl.motion
fl.motion.easing
fl.rsl
fl.text
fl.transitions
fl.transitions.easing
fl.video
flash.accessibility
flash.concurrent
flash.crypto
flash.data
flash.desktop
flash.display
flash.display3D
flash.display3D.textures
flash.errors
flash.events
flash.external
flash.filesystem
flash.filters
flash.geom
flash.globalization
flash.html
flash.media
flash.net
flash.net.dns
flash.net.drm
flash.notifications
flash.permissions
flash.printing
flash.profiler
flash.sampler
flash.security
flash.sensors
flash.system
flash.text
flash.text.engine
flash.text.ime
flash.ui
flash.utils
flash.xml
flashx.textLayout
flashx.textLayout.compose
flashx.textLayout.container
flashx.textLayout.conversion
flashx.textLayout.edit
flashx.textLayout.elements
flashx.textLayout.events
flashx.textLayout.factory
flashx.textLayout.formats
flashx.textLayout.operations
flashx.textLayout.utils
flashx.undo
ga.controls
ga.layouts
ga.model
ga.uiComponents
ga.util
ga.views
ga.wrappers
lc.foundation
lc.foundation.domain
lc.foundation.events
lc.foundation.ui
lc.foundation.util
lc.preloader
lc.procmgmt
lc.procmgmt.commands
lc.procmgmt.domain
lc.procmgmt.events
lc.procmgmt.formbridge
lc.procmgmt.impl
lc.procmgmt.ui.attachments
lc.procmgmt.ui.controls
lc.procmgmt.ui.controls.card
lc.procmgmt.ui.controls.renderer
lc.procmgmt.ui.help
lc.procmgmt.ui.layout
lc.procmgmt.ui.presentationmodel
lc.procmgmt.ui.process
lc.procmgmt.ui.search
lc.procmgmt.ui.startpoint
lc.procmgmt.ui.task
lc.procmgmt.ui.task.form
lc.procmgmt.ui.task.form.commands
lc.procmgmt.ui.tracking
mx.accessibility
mx.automation
mx.automation.air
mx.automation.delegates
mx.automation.delegates.advancedDataGrid
mx.automation.delegates.charts
mx.automation.delegates.containers
mx.automation.delegates.controls
mx.automation.delegates.controls.dataGridClasses
mx.automation.delegates.controls.fileSystemClasses
mx.automation.delegates.core
mx.automation.delegates.flashflexkit
mx.automation.events
mx.binding
mx.binding.utils
mx.charts
mx.charts.chartClasses
mx.charts.effects
mx.charts.effects.effectClasses
mx.charts.events
mx.charts.renderers
mx.charts.series
mx.charts.series.items
mx.charts.series.renderData
mx.charts.styles
mx.collections
mx.collections.errors
mx.containers
mx.containers.accordionClasses
mx.containers.dividedBoxClasses
mx.containers.errors
mx.containers.utilityClasses
mx.controls
mx.controls.advancedDataGridClasses
mx.controls.dataGridClasses
mx.controls.listClasses
mx.controls.menuClasses
mx.controls.olapDataGridClasses
mx.controls.scrollClasses
mx.controls.sliderClasses
mx.controls.textClasses
mx.controls.treeClasses
mx.controls.videoClasses
mx.core
mx.core.windowClasses
mx.data
mx.data.crypto
mx.data.errors
mx.data.events
mx.data.messages
mx.data.mxml
mx.data.offline.errors
mx.data.utils
mx.effects
mx.effects.easing
mx.effects.effectClasses
mx.events
mx.filters
mx.flash
mx.formatters
mx.geom
mx.graphics
mx.graphics.codec
mx.graphics.shaderClasses
mx.logging
mx.logging.errors
mx.logging.targets
mx.managers
mx.messaging
mx.messaging.channels
mx.messaging.config
mx.messaging.errors
mx.messaging.events
mx.messaging.management
mx.messaging.messages
mx.modules
mx.netmon
mx.olap
mx.olap.aggregators
mx.preloaders
mx.printing
mx.resources
mx.rpc
mx.rpc.events
mx.rpc.http
mx.rpc.http.mxml
mx.rpc.livecycle
mx.rpc.mxml
mx.rpc.remoting
mx.rpc.remoting.mxml
mx.rpc.soap
mx.rpc.soap.mxml
mx.rpc.wsdl
mx.rpc.xml
mx.skins
mx.skins.halo
mx.skins.spark
mx.skins.wireframe
mx.skins.wireframe.windowChrome
mx.states
mx.styles
mx.utils
mx.validators
org.osmf.containers
org.osmf.display
org.osmf.elements
org.osmf.events
org.osmf.layout
org.osmf.logging
org.osmf.media
org.osmf.metadata
org.osmf.net
org.osmf.net.dvr
org.osmf.net.httpstreaming
org.osmf.net.metrics
org.osmf.net.qos
org.osmf.net.rtmpstreaming
org.osmf.net.rules
org.osmf.traits
org.osmf.utils
spark.accessibility
spark.automation.delegates
spark.automation.delegates.components
spark.automation.delegates.components.gridClasses
spark.automation.delegates.components.mediaClasses
spark.automation.delegates.components.supportClasses
spark.automation.delegates.skins.spark
spark.automation.events
spark.collections
spark.components
spark.components.calendarClasses
spark.components.gridClasses
spark.components.mediaClasses
spark.components.supportClasses
spark.components.windowClasses
spark.core
spark.effects
spark.effects.animation
spark.effects.easing
spark.effects.interpolation
spark.effects.supportClasses
spark.events
spark.filters
spark.formatters
spark.formatters.supportClasses
spark.globalization
spark.globalization.supportClasses
spark.layouts
spark.layouts.supportClasses
spark.managers
spark.modules
spark.preloaders
spark.primitives
spark.primitives.supportClasses
spark.skins
spark.skins.mobile
spark.skins.mobile.supportClasses
spark.skins.spark
spark.skins.spark.mediaClasses.fullScreen
spark.skins.spark.mediaClasses.normal
spark.skins.spark.windowChrome
spark.skins.wireframe
spark.skins.wireframe.mediaClasses
spark.skins.wireframe.mediaClasses.fullScreen
spark.transitions
spark.utils
spark.validators
spark.validators.supportClasses
xd.core.axm.enterprise.view.components
xd.core.axm.enterprise.view.skins
xd.core.axm.view.components
xd.core.axm.view.components.support

Language Elements

Global Constants
Global Functions
Operators
Statements, Keywords & Directives
Special Types

Appendixes

What's New
Compiler Errors
Compiler Warnings
Run-Time Errors
Migrating to ActionScript 3
Supported Character Sets
MXML Only Tags
Motion XML Elements
Timed Text Tags
List of deprecated elements
Accessibility Implementation Constants
How to Use ActionScript Examples
Legal notices
Packagemx.binding.utils
Classpublic class ChangeWatcher
InheritanceChangeWatcher Inheritance Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The ChangeWatcher class defines utility methods that you can use with bindable Flex properties. These methods let you define an event handler that is executed whenever a bindable property is updated.

More examples



Public Properties
 PropertyDefined By
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  useWeakReference : Boolean
Determines whether the reference to handler is strong or weak.
ChangeWatcher
Public Methods
 MethodDefined By
  
ChangeWatcher(access:Object, handler:Function, commitOnly:Boolean = false, next:ChangeWatcher = null)
Constructor.
ChangeWatcher
  
canWatch(host:Object, name:String, commitOnly:Boolean = false):Boolean
[static] Lets you determine if the host exposes a data-binding event on the property.
ChangeWatcher
  
getEvents(host:Object, name:String, commitOnly:Boolean = false):Object
[static] Returns all binding events for a bindable property in the host object.
ChangeWatcher
  
Retrieves the current value of the watched property or property chain, or null if the host object is null.
ChangeWatcher
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
  
Returns true if each watcher in the chain is attached to at least one change event.
ChangeWatcher
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
  
reset(newHost:Object):void
Resets this ChangeWatcher instance to use a new host object.
ChangeWatcher
  
Sets the handler function.
ChangeWatcher
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
  
Detaches this ChangeWatcher instance, and its handler function, from the current host.
ChangeWatcher
 Inherited
Returns the primitive value of the specified object.
Object
  
watch(host:Object, chain:Object, handler:Function, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher
[static] Creates and starts a ChangeWatcher instance.
ChangeWatcher
Property Detail

useWeakReference

property
public var useWeakReference:Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines whether the reference to handler is strong or weak. A strong reference (the default) prevents handler from being garbage-collected. A weak reference does not.

The default value is false.

Constructor Detail

ChangeWatcher

()Constructor
public function ChangeWatcher(access:Object, handler:Function, commitOnly:Boolean = false, next:ChangeWatcher = null)

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Constructor. Not for public use. This method is called only from the watch() method. See the watch() method for parameter usage.

Parameters
access:Object
 
handler:Function
 
commitOnly:Boolean (default = false)
 
next:ChangeWatcher (default = null)
Method Detail

canWatch

()method
public static function canWatch(host:Object, name:String, commitOnly:Boolean = false):Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Lets you determine if the host exposes a data-binding event on the property.

NOTE: Property chains are not supported by the canWatch() method. They are supported by the watch() method.

Parameters

host:Object — The host of the property. See the watch() method for more information.
 
name:String — The name of the property. See the watch() method for more information.
 
commitOnly:Boolean (default = false) — Set to true if the handler should be called only on committing change events. See the watch() method for more information.

Returns
Booleantrue if host exposes any change events on name.

getEvents

()method 
public static function getEvents(host:Object, name:String, commitOnly:Boolean = false):Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Returns all binding events for a bindable property in the host object.

Parameters

host:Object — The host of the property. See the watch() method for more information.
 
name:String — The name of the property, or property chain. See the watch() method for more information.
 
commitOnly:Boolean (default = false) — Controls inclusion of non-committing change events in the returned value.

Returns
Object — Object of the form { eventName: isCommitting, ... } containing all change events for the property.

getValue

()method 
public function getValue():Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Retrieves the current value of the watched property or property chain, or null if the host object is null. For example:

      watch(obj, ["a","b","c"], ...).getValue() === obj.a.b.c
      

Returns
Object — The current value of the watched property or property chain.

isWatching

()method 
public function isWatching():Boolean

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Returns true if each watcher in the chain is attached to at least one change event. Note that the isWatching() method varies with host, since different hosts may expose different change events for the watcher's chosen property.

Returns
Booleantrue if each watcher in the chain is attached to at least one change event.

reset

()method 
public function reset(newHost:Object):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Resets this ChangeWatcher instance to use a new host object. You can call this method to reuse a watcher instance on a different host.

Parameters

newHost:Object — The new host of the property. See the watch() method for more information.

setHandler

()method 
public function setHandler(handler:Function):void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Sets the handler function.

Parameters

handler:Function — The handler function. This argument must not be null.

unwatch

()method 
public function unwatch():void

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Detaches this ChangeWatcher instance, and its handler function, from the current host. You can use the reset() method to reattach the ChangeWatcher instance, or watch the same property or chain on a different host object.

watch

()method 
public static function watch(host:Object, chain:Object, handler:Function, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Creates and starts a ChangeWatcher instance. A single ChangeWatcher instance can watch one property, or a property chain. A property chain is a sequence of properties accessible from a host object. For example, the expression obj.a.b.c contains the property chain (a, b, c).

Parameters

host:Object — The object that hosts the property or property chain to be watched. You can use the use the reset() method to change the value of the host argument after creating the ChangeWatcher instance. The host maintains a list of handlers to invoke when prop changes.
 
chain:Object — A value specifying the property or chain to be watched. Legal values are:
  • A String containing the name of a public bindable property of the host object.
  • An Object in the form: { name: property name, getter: function(host) { return host[name] } }. The Object contains the name of a public bindable property, and a function which serves as a getter for that property.
  • A non-empty Array containing any combination of the first two options. This represents a chain of bindable properties accessible from the host. For example, to watch the property host.a.b.c, call the method as: watch(host, ["a","b","c"], ...).

Note: The property or properties named in the chain argument must be public, because the describeType() method suppresses all information about non-public properties, including the bindability metadata that ChangeWatcher scans to find the change events that are exposed for a given property. However, the getter function supplied when using the { name, getter } argument form described above can be used to associate an arbitrary computed value with the named (public) property.

 
handler:Function — An event handler function called when the value of the watched property (or any property in a watched chain) is modified. The modification is signaled when any host object in the watcher chain dispatches the event that has been specified in that host object's [Bindable] metadata tag for the corresponding watched property. The default event is named propertyChange.

The event object dispatched by the bindable property is passed to this handler function without modification. By default, Flex dispatches an event object of type PropertyChangeEvent. However, you can define your own event type when you use the [Bindable] metadata tag to define a bindable property.

 
commitOnly:Boolean (default = false) — Set to true if the handler should be called only on committing change events; set to false if the handler should be called on both committing and non-committing change events. Note: the presence of non-committing change events for a property is indicated by the [NonCommittingChangeEvent(<event-name>)] metadata tag. Typically these tags are used to indicate fine-grained value changes, such as modifications in a text field prior to confirmation.
 
useWeakReference:Boolean (default = false) — (default = false) Determines whether the reference to handler is strong or weak. A strong reference (the default) prevents handler from being garbage-collected. A weak reference does not.

Returns
ChangeWatcher — The ChangeWatcher instance, if at least one property name has been specified to the chain argument; null otherwise. Note that the returned watcher is not guaranteed to have successfully discovered and attached itself to change events, since none may have been exposed on the given property or chain by the host. You can use the isWatching() method to determine the watcher's state.

Related API Elements