ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Drag and drop in AIR
if( Clipboard.supportsFilePromise )
{ //Create the promise objects
var filePromise:URLFilePromise = new URLFilePromise();
filePromise.request = new URLRequest("http://example.com/article.html");
filePromise.relativePath = "article.html";
}
var image1Promise:URLFilePromise = new URLFilePromise();
image1Promise.request = new URLRequest("http://example.com/images/img_1.jpg");
image1Promise.relativePath = "images/img_1.html";
var image2Promise:URLFilePromise = new URLFilePromise();
image2Promise.request = new URLRequest("http://example.com/images/img_2.jpg");
image2Promise.relativePath = "images/img_2.jpg";
//Put the promise objects onto the clipboard inside an array
var fileList:Array = new Array( filePromise, image1Promise, image2Promise );
var clipboard:Clipboard = new Clipboard();
clipboard.setData( ClipboardFormats.FILE_PROMISE_LIST_FORMAT, fileList );
//Start the drag operation
NativeDragManager.doDrag( dragSource, clipboard );
Implementing the IFilePromise interface
Adobe AIR 2 and later
To provide file promises for resources that cannot be accessed using a URLFilePromise object, you can implement the
IFilePromise interface in a custom class. The IFilePromise interface defines the methods and properties used by the
AIR runtime to access the data to be written to a file once the file promise is dropped.
An IFilePromise implementation passes another object to the AIR runtime that provides the data for the file promise.
This object must implement the IDataInput interface, which the AIR runtime uses to read the data. For example, the
URLFilePromise class, which implements IFilePromise, uses a URLStream object as the data provider.
AIR can read the data synchronously or asynchronously. The IFilePromise implementation reports which mode of
access is supported by returning the appropriate value in the isAsync property. If asynchronous data access is
provided, the data provider object must implement the IEventDispatcher interface and dispatch the necessary events,
such as open, progress and complete.
You can use a custom class, or one of the following built-in classes, as a data provider for a file promise:
ByteArray (synchronous)
FileStream (synchronous or asynchronous)
Socket (asynchronous)
URLStream (asynchronous)
To implement the IFilePromise interface, you must provide code for the following functions and properties:
open():IDataInput — Returns the data provider object from which the data for the promised file is read. The
object must implement the IDataInput interface. If the data is provided asynchronously, the object must also
implement the IEventDispatcher interface and dispatch the necessary events (see “Using an asynchronous data
provider in a file promise” on page 626).
Last updated 6/6/2012
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