菜鸟求助Flex的问题

Sky-Tiger

To determine whether a given event has default behavior that can be canceled, check
the value of Event class’s instance variable cancelable within a listener registered for
that event.

Sky-Tiger

To determine whether an event currently being dispatched has had its default behavior
prevented, check the return value of the Event class’s instance method
isDefaultPrevented( ) within a listener registered for that event.

Sky-Tiger

By default, when multiple event listeners are registered for a single event type with a
given object, those listeners are triggered in the order in which they registered.
The priority parameter is an integer indicating the order in which the event listener
being registered should be triggered, relative to other listeners registered for the same
event with the same object. Listeners registered with a higher priority are triggered
before listeners registered with a lower priority.

xieye

BS 水虎 你结巴啊

Sky-Tiger

Adding a [Bindable] tag prior to a class definition establishes a binding expression for all public attributes held on that class. Classes using binding must be an implementation of IEventDispatcher because data binding is an event-based notification system to copy source properties to destination properties.

Sky-Tiger

Bindable variables marked as private are available for binding within that class only. Protected variables are available for data binding to the class in which the variable is declared and any subclasses of that class. Public variables are available for data binding to that class, any subclasses, and any external classes.

Sky-Tiger

When you define implicit getter/setter methods as bindable, by adding the [Bindable] metadata tag above the getter declaration, the property can be bound to using dot-notation syntax

Sky-Tiger

Internally, bindable properties held on objects within the Framework dispatch a propertyChange event when their values are updated. The [Bindable] metadata tag accepts an event attribute that you can define with a custom event type:

[Bindable(event="myValueChanged")]


By default, the event attribute is set as propertyChange. If the event attribute is left as the default, destination properties are notified by using that event type internally. If you assign a custom event type to notify objects of updates to a value, you must also dispatch the event explicitly within the class.

Sky-Tiger

When you assign a property of one object (the destination object) to be bound to a property of another object (the source object), an event from the source object is dispatched to notify the destination object of an update to the value. Internally, the property value of the source is copied to the property value of the destination. To bind properties within an MXML declaration, you can use curly braces ({}) or the <mx:Binding> tag. To assign a binding within a component declaration, curly braces are used to wrap the source property and evaluate updates to the value

Sky-Tiger

Updating a destination property value based on a source property value is a quick and easy way to ensure data syncing. When using just property values, the property of the destination must be the same type as that of the source property. There may come a time when you need the binding property to be of a different type or to display different but related values—which is where the power of using functions for binding comes into play.