Besides a host of performance optimizations, improvements for utilizing sensors for low power usage, and memory optimization improvements, here are a few other features packed into KitKat.
Developers can now override the default blue provided in buttons, action bar, hyperlink text, and other UI elements to provide a consistent branding for your applications. Touch feedback now also blends well with the branding.
Support has been included to help apps use the entire real estate on the screen. The full screen functionality has two modes, leanback mode and immersive mode. In lean back mode, in order to return to the menus, the user simply touches anywhere on the screen. In immersive mode, the user needs to swipe from the edge of the device where the system bar is hidden. This is ideal for games, where the user wants to stay in full screen mode, and not accidentally be pulled out by touching the screen in the wrong place.
Two new gestures were added to Android KitKat: double touch and double touch drag. Double touch is exactly what it sounds like, a double tap to the screen in quick succession. Double touch drag, is a tap and then a drag in quick succession. Double touch is used by applications to zoom into an area in the view and double touch can also be used for text selection. Double touch drag is used to zoom centered around the tapped area, here dragging up zooms out and dragging down zooms in.
Step Detector and Step Counter Support
Android has added support for two new sensors: step detection and step counter. Step sensing support, assuming your device includes these sensors in the hardware, allows the device to track the amount of steps walked for a smartphone pedometer.
Android KitKat now gives the developer the ability to add printing from the Android Device, mostly through Wi-Fi. Google also has a service called Google Cloud Print, which will allow users to print documents easily through wifi. You can download a google cloud print app from the Google Play store to print from your KitKat device.
Storage access framework
The KitKat 4.4 Operating system provides a storage provider allowing developers to manipulate stored media in a standard way. The provider class allows developers a way to register a storage provider that utilizes the framework (e.g. a cloud storage system) with Android devices. Google Drive is an example of an application that supports the storage access framework.
Google has added support in KitKat to allow infrared transmission control. Now developers can create apps that communicate through infrared or control a television or vcr via remote control.
Host Card Emulation
Android now supports NFC transactions through Host Card Emulation (basically a smart card). This allows you to swipe bank transactions or other types of transactions supporting this protocol with your phone. This feature requires that an NFC controller be present in the Android device.
This provider gives developers easy access for developing messaging applications with the SMS protocol. It provides a standard mechanism to store and retrieve either SMS or MMS messages on your device.
Now developers can record videos of their application and play them on YouTube. Android KitKat provides a screen recording utility which saves the app recording as an MP4 video file. You can launch the screen recording utility if your USB is connected to your dev environment with the command line: adb shell screenrecord. (This requires that you have the Android SDK installed)