|A version of the Android operating system|
Android 4.4.2 KitKat running on a Nexus 5.
|October 31, 2013|
|Latest release||4.4.4 (KTU84P) / June 19, 2014|
|Preceded by||Android 4.3.1 "Jelly Bean"|
|Succeeded by||Android 5.x "Lollipop"|
|Official website||Official website|
Android 4.4–4.4.4 "KitKat" is a version of the Android mobile operating system developed by Google, spanning versions between 4.4 and 4.4.4. Unveiled on September 3, 2013, KitKat focused primarily on optimizing the operating system for improved performance on entry-level devices with limited resources.
Android 4.4 "KitKat" was officially announced on September 3, 2013. The release was internally codenamed "Key Lime Pie"; John Lagerling, director of Android global partnerships, and his team, decided to drop the name, arguing that "very few people actually know the taste of a key lime pie". Aiming for a codename that was "fun and unexpected", his team pursued the possibility of naming the release "KitKat" instead. Lagerling phoned a representative of Nestlé, who owns the Kit Kat brand and produces the confectionery outside the United States (where it is produced by The Hershey Company under license), and quickly reached a preliminary deal for a promotional collaboration between the two companies, later finalized in a meeting at Mobile World Congress in February 2013. The partnership was not revealed publicly, or even to other Google employees and Android developers (who otherwise continued to internally refer to the OS as "KLP"), until its official announcement in September.
As part of the promotional efforts, Kit Kat bars in the shape of the Android robot logo were produced, while Hershey ran a contest in the United States with prizes of Nexus 7 tablets and Google Play Store credit.
As of July 2016, security vulnerabilities identified in Android 4.4.4 continue to have patches published to the Android Open Source Project.
Continuing on from the focus on improving visual performance and responsiveness on Android 4.1 "Jelly Bean", the main objective of Android 4.4 was to optimize the platform for better performance on low-end devices, without compromising its overall capabilities and functionality. The initiative was codenamed "Project Svelte", which Android head of engineering Dave Burke joked was a weight loss plan after Jelly Bean's "Project Butter" added "weight" to the OS. To simulate lower-spec devices, Android developers used Nexus 4 devices underclocked to run at a reduced CPU speed with only a single core active, 512 MB memory, and at 960×540 display resolution—specifications meant to represent a common low-end Android device.
A development tool known as proctools was developed in order to analyze the memory usage of apps over time, especially those that run background services. This data was used to optimize and decouple Google apps and services found to be inefficient, thus helping to reduce the overall memory usage of Android. Additionally, 4.4 was designed to be more aggressive in managing memory, helping to guard against apps wasting too much memory.
The overall interface of KitKat further downplays the "Holo" interface appearance introduced on 4.0, replacing remaining instances of blue accenting with greys and white (such as the status bar icons). Apps may trigger a translucent status and navigation bar appearance, or trigger a full screen mode ("Immersive mode") to hide them entirely. The launcher also received a refreshed appearance, with the implementation of the translucent navigation bars, and the replacement of the black backdrop in the application drawer with a translucent backdrop. Additionally, action overflow menu buttons in apps are always visible, even on devices with the deprecated "Menu" navigation key. In the Settings menu, users can now specify a default Home (launcher) and text messaging app.
On stock devices, the Messaging and Movie Studio apps were removed; the former was replaced by Google Hangouts, which supports SMS. The AOSP Gallery app was also deprecated in favor of Google+ Photos. In certain apps, a new "Documents" file picker is available.
A new runtime environment known as the Android Runtime (ART), intended to replace the Dalvik virtual machine, was introduced as a technology preview in KitKat. ART is a cross-platform runtime which supports the x86, ARM, and MIPS architectures in both 32-bit and 64-bit environments. Unlike Dalvik, which uses just-in-time compilation (JIT), ART compiles apps upon installation, which are then run exclusively from the compiled version from then on. This technique removes the processing overhead associated with the JIT process, improving system performance.
Devices with 512 MB of RAM or less report themselves as "low RAM" devices. Using an API, apps may detect low RAM devices and modify their functionality accordingly. KitKat also supports zram. WebView components were updated to utilize a version of the Google Chrome rendering engine. A new Storage Access Framework API allows apps to retrieve files in a consistent manner; as part of the framework, a new system file picker allows users to access files from various sources (including those exposed by apps, such as online storage services).
A public API was introduced for developing and managing text messaging clients Sensor batching, step detection and counter APIs were also added. KitKat supports "host card emulation" for near-field communications, which allows apps to emulate a smart card for activities such as mobile payments.
- "Android 4.4 KitKat: What's the point of co-branding?". CNET. CBS Interactive. Retrieved 2 November 2015.
- Kelion, Leo (September 3, 2013). "Android KitKat announced". BBC News. Retrieved September 3, 2013.
- "Kit Kat contest up and running, win one of a 1000 Google Nexus 7 (2013) slates being given away". PhoneArena. Retrieved 2 November 2015.
- "Google Unveils Nexus 5 With Android 4.4 KitKat". PC Magazine. Ziff Davis Media. Retrieved 29 December 2015.
- "Security updates and resources". Android.com. Android Open Source Project. Retrieved 28 July 2016.
- "How Google Shrank Android For Version 4.4 KitKat". ReadWrite. Retrieved 2 November 2015.
- "Android 4.4 KitKat to run "comfortably" on 512MB RAM devices, here's how". PhoneArena. Retrieved 2 November 2015.
- Amadeo, Ron (16 June 2014). "The history of Android: The endless iterations of Google's mobile OS". Ars Technica. Condé Nast. Retrieved 6 July 2014.
- Molen, Brad (November 5, 2013). "Nexus 5 review". Engadget. Retrieved November 11, 2013.
- "Android menu button now on by default on all device with KitKat". PhoneArena. December 9, 2013. Retrieved February 9, 2014.
- "How to remove Hangouts and more Android 4.4 KitKat apps". CNET. CBS Interactive. Retrieved 2 November 2015.
- Ho, Joshua. "Examining MicroSD changes in Android 4.4". Anandtech. Retrieved March 28, 2014.
- "'ART' experiment in Android KitKat improves battery life and speeds up apps". Engadget. Retrieved June 26, 2014.
- Andrei Frumusanu (July 1, 2014). "A Closer Look at Android RunTime (ART) in Android L". AnandTech. Retrieved July 5, 2014.
- "KitKat's WebView is powered by Chromium, enabling Android app developers to use new HTML5 and CSS features". The Next Web. Retrieved 2 November 2015.
- "Getting Your SMS Apps Ready for KitKat". Android Developers Blog. Retrieved October 14, 2013.
- "Google gets around the carriers with Host Card Emulation for NFC payments". NFCWorld.com. Retrieved 2 November 2015.