Features of Android Kitkat 4.4.2

5/24/2018 Features of Android Kitkat 4.4.2

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www.android.com.

Making Android for everyone

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 thathave as little as 5!M" #AM.

$it$at streamlines every ma%or component to reduce memory use and introduces new A&'s

and tools to help you create innovative, responsive, memory-efficient applications.

()Ms building the ne*t generation of Android devices can take advantage of targeted

recommendations and options to run Android 4.4 efficiently, even on low-memory devices.

+alvik ' code cache tuning, kernel samepage merging $/M0, swap to 1#AM, and other

optimi1ations help manage memory. 2ew configuration options let ()Ms tune out-of-

memory levels for processes, set graphics cache si1es, control memory reclaim, and more.

'n Android itself, changes across the system improve memory management and reducememory footprint. 3ore system processes are trimmed to use less heap, and they now more

aggressively protect system memory from apps consuming large amounts of #AM. hen

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.

or developers, Android 4.4 helps you deliver apps that are efficient and responsive on all

devices. A new A&', ActivityManager.is6ow#am+evice0, lets you tune your app7s behavior

to match the device7s memory configuration. 8ou can modify or disable large-memory

features as needed, depending on the use-cases you want to support on entry-level devices.

6earn more about optimi1ing your apps for low-memory devices here.

2ew tools give also give you powerful insight into your app7s memory use. he procstats tooldetails 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. he

meminfo tool is enhanced to make it easier to spot memory trends and issues, and it reveals

additional memory overhead that hasn7t previously been visible.

2ew 23 capabilities through 9ost 3ard )mulation

Android 4.4 introduces new platform support for secure 23-based transactions through

9ost 3ard )mulation 93)0, for payments, loyalty programs, card access, transit passes,

and other custom services. ith 93), any app on an Android device can emulate an 23

smart card, letting users tap to initiate transactions with an app of their choice noprovisioned secure element /)0 in the device is needed. Apps can also use a new #eader

Mode to act as readers for 93) cards and other 23-based transactions.

Android 93) emulates '/(:')3 ;-4 '/(-+)&0 protocol for transmission. hese cards are used by many systems

today, including the e*isting )M?3( 23 payment infrastructure. Android uses Application
http://www.android.com/versions/kit-kat-4-4/http://developer.android.com/training/articles/memory.htmlhttp://developer.android.com/training/articles/memory.htmlhttp://www.android.com/versions/kit-kat-4-4/


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'dentifiers A'+s0 as defined in '/(:')3 ;


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3lient apps can use new A&'s to add printing capabilities to their apps with minimal code

changes. 'n most cases, you would add a print action to your Action "ar and a D' for

choosing items to print. 8ou would also implement A&'s to create print %obs, uery the print

manager for status, and cancel %obs. his lets you print nearly any type of content, from local

images and documents to network data or a view rendered to a canvas.

or broadest compatibility, Android uses &+ as its primary file format for printing. "efore

printing, your app needs to generate a properly paginated &+ version of your content. or

convenience, the printing A&' provides native and eb?iew helper classes to let you create

&+s using standard Android drawing A&'s. 'f your app knows how to draw the content, it

can uickly create a &+ for printing.

Most devices running Android 4.4 will include Coogle 3loud &rint pre-installed as a print

service, as well as several Coogle apps that support printing, including 3hrome, +rive,

Callery, and Euick(ffice.

/torage access framework

A new storage access framework makes it simple for users to browse and open documents,

images, and other files across all of their their preferred document storage providers. A

standard, easy-to-use D' lets users browse files and access recents in a consistent way

across apps and providers.

"o* and others have integrated their services into the storage access framework, giving

users easy access to their documents from apps across the system.


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3loud or local storage services can participate in this ecosystem by implementing a new

document provider class that encapsulates their services. he provider class includes all of

the A&'s needed to register the provider with the system and manage browsing, reading,

and writing documents in the provider. he document provider can give users access to any

remote or local data that can be represented as files from te*t, photos, and wallpapers to

video, audio, and more.

'f you build a document provider for a cloud or local service, you can deliver it to users as

part of your e*isting Android app. After downloading and installing the app, users will have

instant access to your service from any app that participates in the framework. his can help

you gain e*posure and user engagement, since users will find your services more easily.

'f you develop a client app that manages files or documents, you can integrate with the

storage access framework %ust by using new 3#)A)F+(3DM)2 or (&)2F+(3DM)2

intents to open or create files the system automatically displays the standard D' for

browsing documents, including all available document providers.

8ou can integrate your client app one time, for all providers, without any vendor-specificcode. As users add or remove providers, theyGll continue to have access to their preferred

services from your app, without changes or updates needed in your code.

he storage access framework is integrated with the e*isting C)F3(2)2 intent, so

users also have access to all of their previous content and data sources from the new

system D' for browsing. Apps can continue using C)F3(2)2 as a way to let users

import data. he storage access framework and system D' for browsing make it easier for

users to find and import their data from a wider range of sources.

Most devices running Android 4.4 will include Coogle +rive and local storage pre-integrated

as document providers, and Coogle apps that work with files also use the new framework.

6ow-power sensors

/ensor batching

Android 4.4 introduces platform support for hardware sensor batching, a new optimi1ation

that can dramatically reduce power consumed by ongoing sensor activities.

ith sensor batching, Android works with the device hardware to collect and deliver sensor

events efficiently in batches, rather than individually as they are detected. his lets the

device7s application processor remain in a low-power idle state until batches are delivered.

8ou can reuest batched events from any sensor using a standard event listener, and you

can control the interval at which you receive batches. 8ou can also reuest immediatedelivery of events between batch cycles.

/ensor batching is ideal for low-power, long-running use-cases such as fitness, location

tracking, monitoring, and more. 't can makes your app more efficient and it lets you track

sensor events continuously even while the screen is off and the system is asleep.

/ensor batching is currently available on 2e*us 5, and we7re working with our chipset

partners to bring it to more devices as soon as possible.


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Moves and #untastic &edometer are using the hardware step-detector to offer long-running,low-power services.

/tep +etector and /tep 3ounter

Android 4.4 also adds platform support for two new composite sensors step detector and

step counter that let your app track steps when the user is walking, running, or climbing

stairs. hese new sensors are implemented in hardware for low power consumption.

he step detector analy1es accelerometer input to recogni1e when the user has taken a

step, then triggers an event with each step. he step counter tracks the total number of

steps since the last device reboot and triggers an event with each change in the step count.

"ecause the logic and sensor management is built into the platform and underlying

hardware, you don7t need to maintain your own detection algorithms in your app.

/tep detector and counter sensors are available on 2e*us 5, and we7re working with our

chipset partners to bring them to new devices as soon as possible.

/M/ provider

'f you develop a messaging app that uses /M/ or MM/, you can now use a shared /M/

provider and new A&'s to manage your app7s message storage and retrieval. he new /M/

provider and A&'s define a standardi1ed interaction model for all apps that handle /M/ or

MM/ messages.

Along with the new provider and A&'s, Android 4.4 introduces new semantics for receiving

messages and writing to the provider. hen a message is received, the system routes it


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directly to the user7s default messaging app using the new /M/F+)6'?)# intent. (ther

apps can still listen for incoming messages using the /M/F#)3)'?)+ intent. Also, the

system now allows only the default app to write message data to the provider, although other

apps can read at any time. Apps that are not the user7s default can still send messages

the system handles writing those messages to the provider on behalf of the app, so that

users can see them in the default app.

he new provider and semantics help to improve the user7s e*perience when multiple

messaging apps are installed, and they help you to build new messaging features with fully-

supported, forward-compatible A&'s.

2ew ways to build beautiful apps

A new immersive mode lets apps use every pi*el on the screen to show content and capture

touch events.

ull-screen 'mmersive mode

2ow your apps can use every pi*el on the device screen to showcase your content and

capture touch events. Android 4.4 adds a new full-screen immersive mode that lets you

create full-bleed D's reaching from edge to edge on phones and tablets, hiding all system D'

such as the status bar and navigation bar. 't7s ideal for rich visual content such as photos,

videos, maps, books, and games.

'n the new mode, the system D' stays hidden, even while users are interacting with your appor game you can capture touch events from anywhere across the screen, even areas that


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would otherwise be occupied by the system bars. his gives you a great way to create a

larger, richer, more immersive D' in your app or game and also reduce visual distraction.

o make sure that users always have easy, consistent access to system D' from full-screen

immersive mode, Android 4.4 supports a new gesture in immersive mode, an edge swipe

from the top or bottom of the screen now reveals the system D'.

o return to immersive mode, users can touch the screen outside of the bar bounds or wait

for a short period for the bars to auto-hide. or a consistent user e*perience, the new

gesture also works with previous methods of hiding the status bar.

ransitions framework for animating scenes

Most apps structure their flows around several key D' states that e*pose different actions.

Many apps also use animation to help users understand their progress through those states

and the actions available in each. o make it easier to create high-uality animations in your

app, Android 4.4 introduces a new transitions framework.

he transitions framework lets you define scenes, typically view hierarchies, and transitions,which describe how to animate or transform the scenes when the user enters or e*its them.

8ou can use several predefined transition types to animate your scenes based on specific

properties, such as layout bounds, or visibility. here7s also an auto-transition type that

automatically fades, moves, and resi1es views during a scene change. 'n addition, you can

define custom transitions that animate the properties that matter most to your app, and you

can plug in your own animation styles if needed.

ith the transitions framework you can also animate changes to your D' on the fly, without

needing to define scenes. or e*ample, you can make a series of changes to a view

hierarchy and then have the ransitionManager automatically run a delayed transition on

those changes.

(nce you7ve set up transitions, it7s straightforward to invoke them from your app. or

e*ample, you can call a single method to begin a transition, make various changes in your

view hierarchy, and on the ne*t frame animations will automatically begin that animate the

changes you specified.


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Apps can use new window styles to reuest translucent system bars.

or custom control over the transitions that run between specific scenes in your application

flow, you can use the ransitionManager. he ransitionManager lets you define the

relationship between scenes and the transitions that run for specific scene changes.

ranslucent system D' styling

o get the most impact out of your content, you can now use new window styles and themes

to reuest translucent system D', including both the status bar and navigation bar. o ensure

the legibility of navigation bar buttons or status bar information, subtle gradients is shown

behind the system bars. A typical use-case would be an app that needs to show through to a

wallpaper.

)nhanced notification access

2otification listener services can now see more information about incoming notifications that

were constructed using the notification builder A&'s. 6istener services can access a

notification7s actions as well as new e*tras fields te*t, icon, picture, progress,

chronometer, and many others to e*tract cleaner information about the notification and

present the information in a different way.


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3hromium eb?iew

Android 4.4 includes a completely new implementation of eb?iew that7s based on

3hromium. he new 3hromium eb?iew gives you the latest in standards support,

performance, and compatibility to build and display your web-based content.

3hromium eb?iew provides broad support for 9M65, 3//>, and ava/cript. 't supports

most of the 9M65 features available in 3hrome for Android >H. 't also brings an updatedversion of the ava/cript )ngine ?


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Android 4.4 brings formal support for adaptive playback into the Android media framework.

Adaptive playback is an optional feature of video decoders for M&)C-+A/9 and other

formats that enables seamless change in resolution during playback. he client can start to

feed the decoder input video frames of a new resolution and the resolution of the output

buffers change automatically, and without a significant gap.

#esolution switching in Android 4.4 lets media apps offer a significantly better streaming

video e*perience. Apps can check for adaptive playback support at runtime using e*isting

A&'s and implement resolution-switching using new A&'s introduced in Android 4.4.

3ommon )ncryption for +A/9

Android now supports the 3ommon )ncryption 3)230 for M&)C-+A/9, providing a

standard, multiplatform +#M scheme for managing protecting content. Apps can take

advantage of 3)23 through Android7s modular +#M framework and platform A&'s for

supporting +A/9.

9& 6ive /treaming

Android 4.4 updates the platform7s 9& 6ive /treaming 96/0 support to a superset of

version ; of the 96/ specification version 4 of the protocol0. /ee the ') draftfor details.

Audio unneling to +/&

or high-performance, lower-power audio playback, Android 4.4 adds platform support for

audio tunneling to a digital signal processor +/&0 in the device chipset. ith tunneling,

audio decoding and output effects are off-loaded to the +/&, waking the application

processor less often and using less battery.

Audio tunneling can dramatically improve battery life for use-cases such as listening to

music over a headset with the screen off. or e*ample, with audio tunneling, 2e*us 5 offersa total off-network audio playback time of up to =H hours, an increase of over 5HI over non-

tunneled audio.

Media applications can take advantage of audio tunneling on supported devices without

needing to modify code. he system applies tunneling to optimi1e audio playback whenever

it7s available on the device.

?isuali1ation of how the 6oudness)nhancer effect can make speech content more audible.
http://tools.ietf.org/html/draft-pantos-http-live-streaming-07http://tools.ietf.org/html/draft-pantos-http-live-streaming-07


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Audio tunneling reuires support in the device hardware. 3urrently audio tunneling is

available on 2e*us 5 and we7re working with our chipset partners to make it available on

more devices as soon as possible.

Audio monitoring

Apps can use new monitoring tools in the ?isuali1er effect to get updates on the peak and#M/ levels of any currently playing audio on the device. or e*ample, you could use this

creatively in music visuali1ers or to implement playback metering in a media player.

6oudness enhancer

Media playback applications can increase the loudness of spoken content by using the new

6oudness)nhancer effect, which acts as compressor with time constants that are specifically

tuned for speech.

Audio timestamps for improved A? sync

he audio framework can now report presentation timestamps from the audio output 9A6 to

applications, for better audio-video synchroni1ation. Audio timestamps let your app

determine when a specific audio frame will be or was0 presented off-device to the userJ you

can use the timestamp information to more accurately synchroni1e audio with video frames.

i-i 3)#'')+ MiracastK

Android 4.4 devices can now be certified to the i-i Alliance i-i +isplay /pecification as

Miracast compatible. o help with testing, a new ireless +isplay developer option e*poses

advanced configuration controls and settings for ireless +isplay certification. 8ou can

access the option at /ettings L +eveloper options L ireless display certification. 2e*us 5 is

a Miracast certified wireless display device.

#ender/cript 3ompute

&erformance benchmarks for Android 4.4 relative to Android 4.>, run on the same devices

2e*us ;, 2e*us H0.

(ngoing performance improvements

hen your apps use #ender/cript, they7ll benefit from ongoing performance tuning in the

#ender/cript runtime itself, without the need for recompilation. he chart at right shows

performance gains in Android 4.4 on two popular chipsets.


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C&D acceleration

Any app using #ender/cript on a supported device benefits from C&D acceleration, without

code changes or recompiling. /ince the 2e*us H first debuted #ender/cript C&D

acceleration, various other hardware partners have added support.

2ow with Android 4.4, C&D acceleration is available on the 2e*us 5, as well as the 2e*us 4,2e*us ; !H>0, and 2e*us H, and we7re working with our partners to bring it to more

devices as soon as possible.

#ender/cript in the Android 2+$

2ow you can take advantage of #ender/cript directly from your native code. A new 3 A&'

in the Android 2ative +evelopment $it 2+$0 lets you access the same #ender/cript

functionality available through the framework A&'s, including script intrinsics, custom

kernels, and more.

'f you have large, performance-intensive tasks to handle in native code, you can perform

those tasks using #ender/cript and integrate them with your native code. #ender/criptoffers great performance across a wide range of devices, with automatic support for multi-

core 3&Ds, C&Ds, and other processors.

hen you build an app that uses the #ender/cript through the 2+$, you can distribute it to

any device running Android !.! or or higher, %ust like with the #ender/cript support library

available for framework A&'s.

Craphics

C6)/!.H /urfacelinger

Android 4.4 upgrades its /urfacelinger from (penC6 )/ .H to (penC6 )/ !.H.

2ew 9ardware 3omposer support for virtual displays

he latest version of Android 9ardware 3omposer, 93omposer .>, supports hardware

composition of one virtual display in addition to the primary, e*ternal e.g. 9+M'0 display,

and has improved (penC6 )/ interoperability.

2ew ypes of 3onnectivity

2ew "luetooth profiles

Android 4.4 support for two new "luetooth profiles to let apps support a broader range oflow-power and media interactions. "luetooth 9'+ over CA 9(C&0 gives apps a low-

latency link with low-power peripheral devices such as mice, %oysticks, and keyboards.

"luetooth MA& lets your apps e*change messages with a nearby device, for e*ample an

automotive terminal for handsfree use or another mobile device. As an e*tension to

"luetooth A?#3& .>, users can now set absolute volume on the system from their

"luetooth devices.

&latform support for 9(C&, MA&, and A?#3& is built on the "luedroid "luetooth stack

introduced by Coogle and "roadcom in Android 4.!. /upport is available right away on

2e*us devices and other Android-compatible devices that offer compatible "luetooth

capabilities.

'# "lasters


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Android 4.4 introduces platform support for built-in '# blasters, along with a new A&' and

system service that let you create apps to take advantage them.

Dsing the new A&', you can build apps that let users remotely control nearby ?s, tuners,

switches, and other electronic devices. he A&' lets your app check whether the phone or

tablet has an infrared emitter, uery it7s carrier freuencies, and then send infrared signals.

"ecause the A&' is standard across Android devices running Android 4.4 or higher, your app

can support the broadest possible range of vendors without writing custom integration code.

i-i +6/ support

Android 4.4 introduces a seamless way to stream media and other data faster between

devices already on the same i-i network by supporting i-i unneled +irect 6ink /etup

+6/0.

Accessibility

/ystem-wide settings for closed captioning

Android 4.4 now supports a better accessibility e*perience across apps by adding system-

wide preferences for 3losed 3aptioning. Dsers can go to /ettings L Accessibility L 3aptions

to set global captioning preferences, such as whether to show captions and what language,

te*t si1e, and te*t style to use.

Apps that use video can now access the user7s captioning settings and ad%ust presentation

to meet the user7s preferences. A new captioning manager A&' lets you check and monitor

the user7s captioning preferences. he captioning manager provides you with the user7s

preferred captioning state as well as preferred locale, scaling factor, and te*t style. he te*t

style includes foreground and background colors, edge properties, and typeface.

Apps can now refer to the user7s system-wide captions preferences. An e*ample of the

e*pected display style is shown right in the settings.

'n addition, apps that use ?ideo?iew can use a new A&' to pass a captioning stream along

with a video stream for rendering. he system automatically handles the display of the

captions on video frames according to the user7s systemwide settings. 3urrently, ?ideo?iew

supports auto-display of captions in eb? format only.

All apps that show captions should make sure to check the user7s systemwide captioningpreferences and render captions as closely as possible to those preferences. or more


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insight into how specific combinations of settings should look, you can look at a preview of

captions in different languages, si1es, and styles right in the /ettings app.

)nhanced Accessibility A&'s

Android 4.4 e*tends the accessibility A&'s to support more precise structural and semantic

description and observation of onscreen elements. ith the new A&'s, developers canimprove the uality of accessible feedback by providing accessibility services with more

information about on-screen elements.

'n accessibility nodes, developers can now determine whether a node is a popup, get its

input type, and more. 8ou can also use new A&'s to work with nodes that contain grid-like

information, such as lists and tables. or e*ample, you can now specify new supported

actions, collection information, live region modes, and more.

2ew accessibility events let developers more closely follow the changes that are taking

place in window content, and they can now listen for changes in the touch e*ploration mode

on the device.

/upport for international Dsers

+rawable mirroring for #6 locales

'f your app is targeting users who use #6 scripts, you can use a new A&' to declare that a

drawable should be auto-mirrored when the user7s locale setting includes an #6 language.

+eclaring a drawable as auto-mirrored helps you prevent duplication of assets in your app

and reduces the the si1e of your A&$. hen you have drawables that are the reusable for

both 6# and #6 presentations, you can declare the default versions as auto-mirrored and

then omit those +rawables from your #6 resources.

he orce #6 layout option makes it easier to test your app7s locali1ation.

8ou can declare various types of drawables as auto-mirrored in your application code, such

as bitmap, nine-patch, layer, state list, and other drawables. 8ou can also declare a

drawable as auto-mirrored in your resource files by using a new attribute.

orce #6 6ayout

o make it easier to test and debug layout mirroring issues without switching to an #6

language, Android includes a new developer option to force #6 layout direction in all apps.


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he orce #6 layout option switches the device to #6 layout for all locales and displays

te*t in your current language. his can help you find layout issues across your app, without

having to display the app in an #6 language. 8ou can access the option in /ettings L

+eveloper options L orce #6 layout direction.

/ecurity enhancements

/)6inu* enforcing mode0

Android 4.4 updates its /)6inu* configuration from @permissive@ to @enforcing.@ his means

potential policy violations within a /)6inu* domain that has an enforcing policy will be

blocked.

'mproved cryptographic algorithms

Android has improved its security further by adding support for two more cryptographic

algorithms. )lliptic 3urve +igital /ignature Algorithm )3+/A0 support has been added to

the keystore provider improving security of digital signing, applicable to scenarios such assigning of an application or a data connection. he /crypt key derivation function is

implemented to protect the cryptographic keys used for full-disk encryption.

(ther enhancements

(n multiuser devices, ?&2s are now applied per user. his can allow a user to route all

network traffic through a ?&2 without affecting other users on the device. Also, Android now

supports (#'8F/(D#3) level !, and all code is compiled with those protections.

(#'8F/(D#3) has been enhanced to work with clang.

ools for analy1ing memory use

&rocstats

A new tool called procstats helps you analy1e the memory resources your app uses, as well

as the resources used by other apps and services running on the system.

&rocstats keeps track of how apps are running over time, providing data about their

e*ecution durations and memory use to help determine how efficiently they are performing.

his is most important for apps that start services that run in the background, since it lets

you monitor how long they are running and how much #AM they are using while doing so.

&rocstats will also collect data for foreground applications about memory use over time to

determine the overall memory profile of the app.

&rocstats can help you identify background services started by your app. 8ou can keep track

of how long those services continue running and how much #AM they use while doing so.

&rocstats also lets you profile your app while it7s in the foreground, using its memory use

over time to determine its overall memory profile.


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he new procstats tool lets you check the memory use of apps and services over time.

he enhanced meminfo tool lets you see details of memory use for an app.

8ou can access procstats from the adb tool included in the Android /+$, adb shell dumpsys

procstats. Also, for on-device profiling, see the &rocess /tats developer option, below.

(n-device memory status and profiling

Android 4.4 includes a new developer option to make it easier to analy1e your app7s memory

profile while it7s running on any device or emulator. 't7s especially useful to get a view of how

your app uses memory and performs on devices with low #AM. 8ou can access the option

at /ettings L +eveloper options L &rocess stats


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&rocess stats is a convenient way to check your app7s memory use. 8ou can see how yourapp compares to other apps and 1oom in on specific data about your app or it7s background

services.

he &rocess /tats option shows you a variety of high-level metrics on your app7s memory

use, based on data collected using the new procstats service. (n the main screen you can

see a summary of system memory status. Creen indicates relative amount of time spent with

low #AM usage, yellow indicates moderate #AM usage, and red indicates high critical0

#AM usage

"elow the summary is a list summari1ing each app7s memory load on the system. or each

app, a blue bar indicates the relative computed memory load runtime * avgFpss0 of its

process, and a percentage number indicates the relative amount of time spent in thebackground. 8ou can filter the list to show only foreground, background, or cached

processes, and you can include or e*clude system processes. 8ou can also change the

duration of the data collected to >, =, !, or !4 hours, and you can include or e*clude uss

memory.

o take a closer look at a specific app7s memory usage in isolation, tap the app. or each

app, you can now see a summary of the memory consumed and the percentage of the

collection interval that the app has been running. 8ou can also see the average and

ma*imum usage over the collection period, and below the app7s services and the percentage

of time they7ve been running.

Analy1ing your app using the data in &rocess /tats can reveal issues and suggest possibleoptimi1ations for your app. or e*ample, if your app is running longer than it should or using


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too much memory over a period of time, there could be bugs in your code that you can

resolve to improve your app7s performance, especially when running on a device with low

#AM.

Features of Android Kitkat 4.4.2

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