An Android 4.3 build for the Samsung Galaxy S4 leaked a few days ago and it was found to contain some hidden enhancements that point the way to some new features in the future. They have to do with notifications.
The first is a Notifications screen, which acts as history of all your recent notifications, even the ones you’ve dismissed (those are the grayed out ones, the others are notifications still visible in the notification area).
Android 4.3 will also allow apps to read what notifications are displayed through an additional permission. These apps will also be able to dismiss notifications and interact with them (e.g. hit the Reply or Delete buttons on an email notification).
<string name=”notification_listener_security_warning_summary”>%1$s will be able to read all notifications posted by the system or any installed app, which may include personal information such as contact names and the text of messages sent to you. It will also be able to dismiss these notifications or touch action buttons within them.</string>
That will be great for smartwatches and the likes, which display notifications from your phone (and are currently doing it through the unrelated Accessibility API). But this will also enable other applications, like sending notifications to your desktop. Apps like Tasker and others also need to read notifications to perform some action and currently do it with the Accessibility API, but they’ll be able to move to the new, more appropriate API.
Such apps are called Notification listeners and there’s a Notification access screen that shows you which apps have access to your notification (which could be a privacy concern, after all notifications often contain messages to you).
Another enticing possibility is replacement notification areas – currently you can change the launcher and the lockscreen, but not the notification. However, the needed permissions (to hide the stock notification area) have not been found (yet!).