Non-application
content cannot access the File objects that result when files are dragged
into an AIR application. Nor is it possible to pass one of these
File objects to application content through a sandbox bridge. (The
object properties must be accessed during serialization.) However,
you can still drop files in your application by listening for the
AIR nativeDragDrop events on the HTMLLoader object.
Normally, if a user drops a file into a frame that hosts non-application
content, the drop event does not propagate from the child to the
parent. However, since the events dispatched by the HTMLLoader (which
is the container for all HTML content in an AIR application) are
not part of the HTML event flow, you can still receive the drop
event in application content.
To receive the event for a file drop, the parent document adds
an event listener to the HTMLLoader object using the reference provided
by
window.htmlLoader
:
window.htmlLoader.addEventListener("nativeDragDrop",function(event){
var filelist = event.clipboard.getData(air.ClipboardFormats.FILE_LIST_FORMAT);
air.trace(filelist[0].url);
});
The
NativeDragEvent objects behave like their HTML event counterparts,
but the names and data types of some of the properties and methods
are different. For example, the HTML event
dataTransfer
property serves
the same purpose as the ActionScript event
clipboard
property.
For more information about using these classes, refer to
Adobe ActionScript 3.0 Developer's Guide
and
the
ActionScript 3.0 Reference for the Adobe
Flash Platform
.
The following example uses a parent document that loads a child
page into a remote sandbox (http://localhost/). The parent listens
for the
nativeDragDrop
event on the HTMLLoader
object and traces out the file url.
<html>
<head>
<title>Drag-and-drop in a remote sandbox</title>
<script language="javascript" type="text/javascript" src="AIRAliases.js"></script>
<script language="javascript">
window.htmlLoader.addEventListener("nativeDragDrop",function(event){
var filelist = event.clipboard.getData(air.ClipboardFormats.FILE_LIST_FORMAT);
air.trace(filelist[0].url);
});
</script>
</head>
<body>
<iframe src="child.html"
sandboxRoot="http://localhost/"
documentRoot="app:/"
frameBorder="0" width="100%" height="100%">
</iframe>
</body>
</html>
The child document must present a valid drop target by calling
the Event object
preventDefault()
method in the
HTML
dragenter
and
dragover
event handlers.
Otherwise, the drop event can never occur.
<html>
<head>
<title>Drag and drop target</title>
<script language="javascript" type="text/javascript">
function preventDefault(event){
event.preventDefault();
}
</script>
</head>
<body ondragenter="preventDefault(event)" ondragover="preventDefault(event)">
<div>
<h1>Drop Files Here</h1>
</div>
</body>
</html>
