ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Drag and drop in AIR
}
}
}
{
}
fileContents.writeUTFBytes( 'S' );
//Important: the ByteArray is read from the current position
fileContents.position = 0;
return fileContents;
public function close():void
{
//Nothing needs to be closed in this case.
}
public function reportError(e:ErrorEvent):void
{
trace("Something went wrong: " + e.errorID + " - " + e.type + ", " + e.text );
}
In practice, synchronous file promises have limited utility. If the amount of data is small, you could just as easily create
a file in a temporary directory and add a normal file list array to the drag-and-drop clipboard. On the other hand, if
the amount of data is large or generating the data is computationally expensive, a long synchronous process is
necessary. Long synchronous processes can block UI updates for a noticeable amount of time and make your
application seem unresponsive. To avoid this problem, you can create an asynchronous data provider driven by a
timer.
Using an asynchronous data provider in a file promise
Adobe AIR 2 and later
When you use an asynchronous data provider object, the IFilePromise isAsync property must be true and the object
returned by the open() method must implement the IEventDispatcher interface. The runtime listens for several
alternative events so that different built-in objects can be used as a data provider. For example, progress events are
dispatched by FileStream and URLStream objects, whereas socketData events are dispatched by Socket objects. The
runtime listens for the appropriate events from all of these objects.
The following events drive the process of reading the data from the data provider object:
Event.OPEN — Informs the runtime that the data source is ready.
ProgressEvent.PROGRESS — Informs the runtime that data is available. The runtime will read the amount of
available data from the data provider object.
ProgressEvent.SOCKET_DATA — Informs the runtime that data is available. The socketData event is dispatched
by socket-based objects. For other object types, you should dispatch a progress event. (The runtime listens for
both events to detect when data can be read.)
Event.COMPLETE — Informs the runtime that the data has all been read.
Event.CLOSE — Informs the runtime that the data has all been read. (The runtime listens for both close and
complete for this purpose.)
IOErrorEvent.IOERROR — Informs the runtime that an error reading the data has occurred. The runtime aborts
file creation and calls the IFilePromise close() method.
Last updated 6/6/2012
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