It was interesting to read Johan Thelin's blog entry on moving to KDE 4, particularly how much he likes the device notifier. I say this because that Plasma widget has been seeing a flurry of activity for KDE 4.4 so the timing was pretty neat.
The device notifier debuted in KDE 4.0 and the primary goal was to make the announcement of devices that become available during a session feel more organic. As a starting point, we harmonized it with the desktop workspace by providing a Plasmoid for this functionality. In past releases these announcements were accomplished using a pop-up dialog using a window that looked like any other application window.
In KDE 4, we've tried to make a clear distinction between what is "application" (and therefore the use focus) and what is "workspace" (and therefore is perceived as part of the "system" and separate from the application). This separation allows the user to focus with clarity on the task at hand while allowing the workspace to both communicate with and provide opportunity for interaction in a clear fashion.
Having device announcements happen as part of the workspace user interface was therefore a natural decision, and Alexis made that idea a reality with the first version of the notifier. It was decided that device notifications have some similar but mostly different usage requirements than other system notifications, so a separate Plasmoid was created along with a couple of DataEngines (hotplug and soliddevices) for easy of re-use by other Plasmoids that may come along.
Although there were some nice improvements over time to the device notifier widget, there were several areas of potential improvement. For one, it never looked as visually continuous with other Plasmoids due to using a standard Qt list view rather than something on the canvas. For another, it fell back to using a pop-up dialog when there were multiple available actions for a given device.
The device notifier saw one full rewrite attempt but that effort didn't achieved a final production state. Recently, it saw another, this time thanks to the combined efforts of Giulio Camuffo and Jacopo De Simoi, with Marco Martin and I helping out with feedback and some patches. The new Plasmoid is in kdereview and will be a part of KDE 4.4. There are still a few areas of polish left (biggest remaining TODO is keyboard navigation) but given Johan's blog I figured it might be nice to share what we have now.
As you can see in the screencast (which has no audio) below, the new widget rather nicely addresses both of the major outstanding issues with the current device notifier. It also adds two new features: the ability to hide certain items and the ability to also display fixed devices. Both are optional and don't interfere with the primary interface and only one new item appears in the configuration dialog.
You can grab the OGG file here or watch the screencast via blip.tv below (though it is inexplicably enlarged; very odd):