Kevin Hoyt

Depending on the dominant browser for your web application, and the security settings therein, you may have been able to work with text on the system clipboard via JavaScript. If you’re a Flash developer, the Flash Player allows you to send text to the clipboard, but not to get anything at all from it. This leaves you branching out to JavaScript, checking the browser and settings, and then potentially being able to work only with text. Historically, this has been painful for all parties involved, but this is about to change! The Apollo Beta will introduce system clipboard support for text, bitmap data, and even lists of files.

This works through the use of a the ClipboardManager class. The ClipboardManager class has a data property the represents the system clipboard. You can put text, bitmap data, or files on the clipboard, or retrieve them from it using that data property. You don’t get access to the ClipboardManager.data property however, unless you’re inside an method enclosure called by the clipboard manager. What?

It essentially works like this:

1. Your application listens for events that should trigger clipboard access (cut or paste)
3. The application then calls the static method ClipboardManager.accessClipboard( func )
4. The ClipboardManager.accessClipboard() method takes a function to call when the clipboard is available as an argument
5. From within that function, and only within that function, you can access the ClipboardManager.data property directly

The code representation of that looks something like this:

document.getElementById( "btnPaste" ).addEventListener( "click", myEventHandler );

function myEventHandler()
{
    apollo.ClipboardManager.accessClipboard( myClipboard );
}

function myClipboard()
{
    var myData = apollo.ClipboardManager.data.dataForFormat(
        apollo.TransferableDataFormats.BITMAP_FORMAT,
        apollo.TransferableTransferMode.CLONE_PREFERRED );
}

There’s even support for multiple representations of what’s headed out to the clipboard. For example, you might chose to have a comma-separated text block for a list of data objects, but you can also put the data in a file and put the file on the clipboard. In this fashion, it’s actually up to the target application to decide what clipboard representation to use, and then to access and apply that data accordingly. This holds true for incoming data as well.

When you think of the types of data that end up on the clipboard, some pretty interesting possibilities start coming to mind. Ever press the “print screen” button? That ends up on the clipboard as bitmap data. Ever highlight a bunch of files and then copy them somewhere? What if you pasted that group of files into an Apollo application for additional processing such as being upload to a server? Here’s an example that allows you to copy a graphic from a web page (bitmap data), paste that into your Apollo application, and then send it back to the clipboard and onto the desktop.

This entry was posted on Friday, June 8th, 2007 at 7:15 pm and is filed under AIR, JavaScript. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.