ActionScript® 3.0 Reference for the Adobe® Flash® Platform
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flashx.textLayout.events 

FlowOperationEvent  - AS3

Packageflashx.textLayout.events
Classpublic class FlowOperationEvent
InheritanceFlowOperationEvent Inheritance Event Inheritance Object

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

A TextFlow instance dispatches this event just before an operation commences and again just after an operation completes. Although the event object dispatched in both cases is an instance of FlowOperationEvent, the events dispatched before and after an operation differ in significant ways.

Before any operation is carried out, a TextFlow object dispatches a FlowOperationEvent with its type property set to FlowOperationEvent.FLOW_OPERATION_BEGIN. You can determine what type of operation is about to commence by checking the operation property. Events of type FLOW_OPERATION_BEGIN are cancellable, which means that if you decide that the operation should not proceed, you can call Event.PreventDefault() to cancel the operation. If you cancel the operation, the operation is not performed and the FLOW_OPERATION_END event is not dispatched. You may also choose to call back into the EditManager to do another operation before the operation that triggered the event is done. If you do this, the operations you initiate in your event handler will be undone as a single operation with the operation that triggered the event.

If you allow the operation to proceed, TextFlow will dispatch a FlowOperationEvent upon completion of the operation with its type property set to FlowOperationEvent.FLOW_OPERATION_END. This event is dispatched before Flash Player throws any errors that may have occurred as a result of the operation. This gives you an opportunity to process the error before Flash Player throws the error. You can access the error through the event's error property. If you choose to handle the error in your event handler, you can prevent Flash Player from throwing the error by cancelling the FLOW_OPERATION_END event by calling Event.preventDefault(). You may also choose to call back into the EditManager to do some additional operations. If you do this, the operations that result will be undone as a unit with the operation that triggered the event.

View the examples

Related API Elements



Public Properties
 PropertyDefined By
 Inheritedbubbles : Boolean
[read-only] Indicates whether an event is a bubbling event.
Event
 Inheritedcancelable : Boolean
[read-only] Indicates whether the behavior associated with the event can be prevented.
Event
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
 InheritedcurrentTarget : Object
[read-only] The object that is actively processing the Event object with an event listener.
Event
  error : Error
The error thrown, if any, during an operation.
FlowOperationEvent
 InheritedeventPhase : uint
[read-only] The current phase in the event flow.
Event
  level : int
Operations may be merged into composite operations through nesting.
FlowOperationEvent
  operation : FlowOperation
The operation that is about to begin or has just ended.
FlowOperationEvent
 Inheritedtarget : Object
[read-only] The event target.
Event
 Inheritedtype : String
[read-only] The type of event.
Event
Public Methods
 MethodDefined By
  
FlowOperationEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false, operation:FlowOperation = null, level:int = 0, error:Error = null)
Creates an event object that contains information about a flow operation.
FlowOperationEvent
 Inherited
Duplicates an instance of an Event subclass.
Event
 Inherited
formatToString(className:String, ... arguments):String
A utility function for implementing the toString() method in custom ActionScript 3.0 Event classes.
Event
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Checks whether the preventDefault() method has been called on the event.
Event
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
Cancels an event's default behavior if that behavior can be canceled.
Event
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Prevents processing of any event listeners in the current node and any subsequent nodes in the event flow.
Event
 Inherited
Prevents processing of any event listeners in nodes subsequent to the current node in the event flow.
Event
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns a string containing all the properties of the Event object.
Event
 Inherited
Returns the primitive value of the specified object.
Object
Public Constants
 ConstantDefined By
  FLOW_OPERATION_BEGIN : String = "flowOperationBegin"
[static] Defines the value of the type property of a flowOperationBegin event object.
FlowOperationEvent
  FLOW_OPERATION_COMPLETE : String = "flowOperationComplete"
[static] Defines the value of the type property of a flowOperationComplete event object.
FlowOperationEvent
  FLOW_OPERATION_END : String = "flowOperationEnd"
[static] Defines the value of the type property of a flowOperationEnd event object.
FlowOperationEvent
Property Detail

error

property
error:Error

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

The error thrown, if any, during an operation. If an error occurs during an operation, a reference to the error object is attached to the FLOW_OPERATION_END event. This give you the opportunity to deal with the error before Flash Player throws the error. If you cancel the event, Flash Player will not throw the error.



Implementation
    public function get error():Error
    public function set error(value:Error):void

level

property 
level:int

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

Operations may be merged into composite operations through nesting. This flag describes the nesting level of the operation.



Implementation
    public function get level():int
    public function set level(value:int):void

operation

property 
operation:FlowOperation

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

The operation that is about to begin or has just ended.



Implementation
    public function get operation():FlowOperation
    public function set operation(value:FlowOperation):void

Related API Elements

Constructor Detail

FlowOperationEvent

()Constructor
public function FlowOperationEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false, operation:FlowOperation = null, level:int = 0, error:Error = null)

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

Creates an event object that contains information about a flow operation.

Parameters
type:String — The type of the event. Event listeners can access this information through the inherited type property. There are two types: FlowOperationEvent.FLOW_OPERATION_BEGIN; FlowOperationEvent.FLOW_OPERATION_END.
 
bubbles:Boolean (default = false) — Indicates whether an event is a bubbling event.This event does not bubble.
 
cancelable:Boolean (default = false) — Indicates whether the behavior associated with the event can be prevented. This event can be cancelled by calling the Event.preventDefault() method in your event handler function.
 
operation:FlowOperation (default = null) — The FlowOperation that is about to commence or that has just ended.
 
level:int (default = 0) — Any Error generating during the operation.
 
error:Error (default = null)
Constant Detail

FLOW_OPERATION_BEGIN

Constant
public static const FLOW_OPERATION_BEGIN:String = "flowOperationBegin"

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

Defines the value of the type property of a flowOperationBegin event object. Dispatched before an operation is executed. Cancelling this event blocks the operation.

FLOW_OPERATION_COMPLETE

Constant 
public static const FLOW_OPERATION_COMPLETE:String = "flowOperationComplete"

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

Defines the value of the type property of a flowOperationComplete event object. Dispatched after all operations including pending and composite operations are completed, composition is finished and the display is scrolled.

FLOW_OPERATION_END

Constant 
public static const FLOW_OPERATION_END:String = "flowOperationEnd"

Language Version: ActionScript 3.0
Runtime Versions: Flash Player 10, AIR 1.5

Defines the value of the type property of a flowOperationEnd event object. Dispatched after an operation completes. Any errors are stored in OperationEvent.error. If there is an error, cancelling this event blocks the rethrow of the error. Generally speaking all errors are likely to be fatal.

Changing an operation at this time (after it has been executed) may fail.

FlowOperationEvent_example.as

This example shows how to create an event handler that listens for the beginning and end of a text flow operation. The two key steps are to call the addEventListener() method on the text flow and to create an event handler function.

The call to addEventListener() is made on the TextFlow instance. You can use the simple string "flowOperationBegin" or "flowOperationEnd", but it is safer to use the static constant FlowOperationEvent.FLOW_OPERATION_BEGIN or FlowOperationEvent.FLOW_OPERATION_END, respectively.

The event handler functions in this example are named opBeginHandler() and opEndHandler(). The opBeginHandler() method uses the trace() function to produce a trace statement that indicates that a paste operation has started. The opEndHandler() method also uses the trace() function, but produces a trace statement only if an error occurs.

package flashx.textLayout.events.examples
{
    import flash.display.Sprite;
    
    import flashx.textLayout.compose.StandardFlowComposer;
    import flashx.textLayout.container.ContainerController;
    import flashx.textLayout.conversion.TextConverter;
    import flashx.textLayout.edit.EditManager;
    import flashx.textLayout.elements.TextFlow;
    import flashx.textLayout.events.FlowOperationEvent;
    import flashx.textLayout.operations.FlowOperation;
    import flashx.textLayout.operations.PasteOperation;
    import flashx.undo.UndoManager;

    public class FlowOperationEvent_example extends Sprite
    {
        private var inputContainer:Sprite;
        private var inputTextFlow:TextFlow;
        private var inputController:ContainerController;
        private var inputEditManager:EditManager;
        private var inputUndoManager:UndoManager;

        public function FlowOperationEvent_example()
        {
            var replaceText:String = "paste text here";
            inputTextFlow = new TextFlow();

            inputContainer = new Sprite();
            inputContainer.x = 30;
            inputContainer.y = 100;

             this.stage.addChild( inputContainer );

            inputController = new ContainerController(inputContainer, 225, 20);
            inputController.verticalScrollPolicy = flashx.textLayout.container.ScrollPolicy.OFF;

            inputTextFlow = TextConverter.importToFlow(replaceText, TextConverter.PLAIN_TEXT_FORMAT);
            inputTextFlow.flowComposer = new StandardFlowComposer(); 
            inputTextFlow.flowComposer.addController(inputController);

            inputUndoManager = new UndoManager();
            inputEditManager = new EditManager(inputUndoManager);
            inputTextFlow.interactionManager = inputEditManager;

            inputTextFlow.addEventListener(FlowOperationEvent.FLOW_OPERATION_BEGIN, opBeginHandler);
            inputTextFlow.addEventListener(FlowOperationEvent.FLOW_OPERATION_END, opEndHandler);
            inputTextFlow.flowComposer.updateAllControllers();
        }

        private function opBeginHandler(evt:FlowOperationEvent):void { 
            var flowOp:FlowOperation = evt.operation; 
            if(flowOp is PasteOperation) {
                trace("You can cancel or modify the paste operation in this event handler.");
            }
        }

        private function opEndHandler(evt:FlowOperationEvent):void { 
            var flowOp:FlowOperation = evt.operation; 
            if(evt.error) {
                trace("You can handle the error here and call preventDefault().");
            }
        }
    }
}