Welcome to Android 4.4 KitKat!
Android KitKat brings all of Android's most innovative, most beautiful, and most useful features to more devices everywhere.
This document provides a glimpse of what's new for developers.
Find out more about KitKat for consumers at www.android.com.
Android 4.4 is designed to run fast, smooth, and responsively on a much broader range of devices than ever before — including on millions of entry-level devices around the world that have as little as 512MB RAM.
KitKat streamlines every major component to reduce memory use and introduces new APIs and tools to help you create innovative, responsive, memory-efficient applications.
OEMs building the next generation of Android devices can take advantage of targeted recommendations and options to run Android 4.4 efficiently, even on low-memory devices. Dalvik JIT code cache tuning, kernel samepage merging (KSM), swap to zRAM, and other optimizations help manage memory. New configuration options let OEMs tune out-of-memory levels for processes, set graphics cache sizes, control memory reclaim, and more.
In Android itself, changes across the system improve memory management and reduce memory footprint. Core system processes are trimmed to use less heap, and they now more aggressively protect system memory from apps consuming large amounts of RAM. When multiple services start at once — such as when network connectivity changes — Android now launches the services serially, in small groups, to avoid peak memory demands.
For developers, Android 4.4 helps you deliver apps that are efficient and responsive on all devices. A new API, ActivityManager.isLowRamDevice(), lets you tune your app's behavior to match the device's memory configuration. You can modify or disable large-memory features as needed, depending on the use-cases you want to support on entry-level devices. Learn more about optimizing your apps for low-memory devices here.
New tools give also give you powerful insight into your app's memory use. The procstats tool details memory use over time, with run times and memory footprint for foreground apps and background services. An on-device view is also available as a new developer option. The meminfo tool is enhanced to make it easier to spot memory trends and issues, and it reveals additional memory overhead that hasn't previously been visible.
New NFC capabilities through Host Card Emulation
Android 4.4 introduces new platform support for secure NFC-based transactions through Host Card Emulation (HCE), for payments, loyalty programs, card access, transit passes, and other custom services. With HCE, any app on an Android device can emulate an NFC smart card, letting users tap to initiate transactions with an app of their choice — no provisioned secure element (SE) in the device is needed. Apps can also use a new Reader Mode to act as readers for HCE cards and other NFC-based transactions.
Android HCE emulates ISO/IEC 7816 based smart cards that use the contactless ISO/IEC 14443-4 (ISO-DEP) protocol for transmission. These cards are used by many systems today, including the existing EMVCO NFC payment infrastructure. Android uses Application Identifiers (AIDs) as defined in ISO/IEC 7816-4 as the basis for routing transactions to the correct Android applications.
Apps declare the AIDs they support in their manifest files, along with a category identifier that indicates the type of support available (for example, "payments"). In cases where multiple apps support the same AID in the same category, Android displays a dialog that lets the user choose which app to use.
When the user taps to pay at a point-of-sale terminal, the system extracts the preferred AID and routes the transaction to the correct application. The app reads the transaction data and can use any local or network-based services to verify and then complete the transaction.
Android HCE requires an NFC controller to be present in the device. Support for HCE is already widely available on most NFC controllers, which offer dynamic support for both HCE and SE transactions. Android 4.4 devices that support NFC will include Tap & Pay for easy payments using HCE.
More at : https://developer.android.com/about/versions/kitkat.html
Image Courtesy : Android.com