Android 1.6 Compatibility Definition

Android Compatibility Definition: Android 1.6
Android 1.6 r2
Google Inc.
compatibility@android.com

1. Introduction
This document enumerates the requirements that must be met in order for mobile phones to be
compatible with Android 1.6. This definition assumes familiarity with the Android Compatibility Program
[Resources, 1].
The use of "must", "must not", "required", "shall", "shall not", "should", "should not", "recommended",
"may" and "optional" is per the IETF standard defined in RFC2119 [Resources, 2].
As used in this document, a "device implementer" or "implementer" is a person or organization developing
a hardware/software solution running Android 1.6. A "device implementation" or "implementation" is the
hardware/software solution so developed.
To be considered compatible with Android 1.6, device implementations:
1. MUST meet the requirements presented in this Compatibility Definition, including any documents
incorporated via reference.
2. MUST pass the Android Compatibility Test Suite (CTS) available as part of the Android Open
Source Project [Resources, 3]. The CTS tests most, but not all, components outlined in this
document.
Where this definition or the CTS is silent, ambiguous, or incomplete, it is the responsibility of the device
implementer to ensure compatibility with existing implementations. For this reason, the Android Open
Source Project [Resources, 4] is both the reference and preferred implementation of Android. Device
implementers are strongly encouraged to base their implementations on the "upstream" source code
available from the Android Open Source Project. While some components can hypothetically be replaced
with alternate implementations this practice is strongly discouraged, as passing the CTS tests will become
substantially more difficult. It is the implementer's responsibility to ensure full behavioral compatibility with
the standard Android implementation, including and beyond the Compatibility Test Suite.
2. Resources
This Compatibility Definition makes reference to a number of resources that can be obtained here.
1. Android Compatibility Program Overview: https://sites.google.com/a/android.com/compatibility/
how-it-works
2. IETF RFC2119 Requirement Levels: http://www.ietf.org/rfc/rfc2119.txt
3. Compatibility Test Suite: http://sites.google.com/a/android.com/compatibility/compatibility-test-
suite--cts
4. Android Open Source Project: http://source.android.com/
5. API definitions and documentation: http://developer.android.com/reference/packages.html
6. Content Providers: http://code.google.com/android/reference/android/provider/package-
summary.html
7. Available Resources: http://code.google.com/android/reference/available-resources.html
8. Android Manifest files: http://code.google.com/android/devel/bblocks-manifest.html
9. Android Permissions reference: http://developer.android.com/reference/android/
Manifest.permission.html
10. Build Constants: http://developer.android.com/reference/android/os/Build.html
11. WebView: http://developer.android.com/reference/android/webkit/WebView.html
12. Gears Browser Extensions: http://code.google.com/apis/gears/

13. Dalvik Virtual Machine specification, found in the dalvik/docs directory of a source code
checkout; also available at http://android.git.kernel.org/?p=platform/
dalvik.git;a=tree;f=docs;h=3e2ddbcaf7f370246246f9f03620a7caccbfcb12;hb=HEAD
14. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
15. Notifications: http://developer.android.com/guide/topics/ui/notifiers/notifications.html
16. Status Bar icon style guide: http://developer.android.com/guide/practices/ui_guideline
/icon_design.html#statusbarstructure
17. Search Manager: http://developer.android.com/reference/android/app/SearchManager.html
18. Toast: http://developer.android.com/reference/android/widget/Toast.html
19. Apps For Android: http://code.google.com/p/apps-for-android
20. Android apk file description: http://developer.android.com/guide/topics/fundamentals.html
21. Android Debug Bridge (adb): http://code.google.com/android/reference/adb.html
22. Dalvik Debug Monitor Service (ddms): http://code.google.com/android/reference/ddms.html
23. Monkey: http://developer.android.com/guide/developing/tools/monkey.html
24. Display-Independence Documentation:
25. Configuration Constants: http://developer.android.com/reference/android/content/res/
Configuration.html
26. Display Metrics: http://developer.android.com/reference/android/util/DisplayMetrics.html
27. Camera: http://developer.android.com/reference/android/hardware/Camera.html
28. Sensor coordinate space: http://developer.android.com/reference/android/hardware/
SensorEvent.html
29. Android Security and Permissions reference: http://developer.android.com/guide/topics/security/
security.html
Many of these resources are derived directly or indirectly from the Android 1.6 SDK, and will be
functionally identical to the information in that SDK's documentation. In any cases where this
Compatibility Definition disagrees with the SDK documentation, the SDK documentation is considered
authoritative. Any technical details provided in the references included above are considered by inclusion
to be part of this Compatibility Definition.
3. Software
The Android platform includes both a set of managed ("hard") APIs, and a body of so-called "soft" APIs
such as the Intent system, native-code APIs, and web-application APIs. This section details the hard and
soft APIs that are integral to compatibility, as well as certain other relevant technical and user interface
behaviors. Device implementations MUST comply with all the requirements in this section.
3.1. Managed API Compatibility
The managed (Dalvik-based) execution environment is the primary vehicle for Android applications. The
Android application programming interface (API) is the set of Android platform interfaces exposed to
applications running in the managed VM environment. Device implementations MUST provide complete
implementations, including all documented behaviors, of any documented API exposed by the Android
1.6 SDK, such as:
1. Core Android Java-language APIs [Resources, 5].
2. Content Providers [Resources, 6].
3. Resources [Resources, 7].
4. AndroidManifest.xml attributes and elements [Resources, 8].

Device implementations MUST NOT omit any managed APIs, alter API interfaces or signatures, deviate
from the documented behavior, or include no-ops, except where specifically allowed by this Compatibility
Definition.
3.2. Soft API Compatibility
In addition to the managed APIs from Section 3.1, Android also includes a significant runtime-only "soft"
API, in the form of such things such as Intents, permissions, and similar aspects of Android applications
that cannot be enforced at application compile time. This section details the "soft" APIs and system
behaviors required for compatibility with Android 1.6. Device implementations MUST meet all the
requirements presented in this section.
3.2.1. Permissions
Device implementers MUST support and enforce all permission constants as documented by the
Permission reference page [Resources, 9]. Note that Section 10 lists addtional requirements related to
the Android security model.
3.2.2. Build Parameters
The Android APIs include a number of constants on the android.os.Build class [Resources, 10] that are
intended to describe the current device. To provide consistent, meaningful values across device
implementations, the table below includes additional restrictions on the formats of these values to which
device implementations MUST conform.
Parameter
Comments
The version of the currently-executing Android system, in human-
android.os.Build.VERSION.RELEASE
readable format. For Android 1.6, this field MUST have the string value
"1.6".
The version of the currently-executing Android system, in a format
android.os.Build.VERSION.SDK
accessible to third-party application code. For Android 1.6, this field
MUST have the integer value 4.
A value chosen by the device implementer designating the specific build
of the currently-executing Android system, in human-readable format.
This value MUST NOT be re-used for different builds shipped to end
android.os.Build.VERSION.INCREMENTAL users. A typical use of this field is to indicate which build number or
source-control change identifier was used to generate the build. There
are no requirements on the specific format of this field, except that it
MUST NOT be null or the empty string ("").
A value chosen by the device implementer identifying the specific internal
hardware used by the device, in human-readable format. A possible use
android.os.Build.BOARD
of this field is to indicate the specific revision of the board powering the
device. There are no requirements on the specific format of this field,
except that it MUST NOT be null or the empty string ("").
A value chosen by the device implementer identifying the name of the
android.os.Build.BRAND
company, organization, individual, etc. who produced the device, in
human-readable format. A possible use of this field is to indicate the OEM

and/or carrier who sold the device. There are no requirements on the
specific format of this field, except that it MUST NOT be null or the empty
string ("").
A value chosen by the device implementer identifying the specific
configuration or revision of the body (sometimes called "industrial
android.os.Build.DEVICE
design") of the device. There are no requirements on the specific format
of this field, except that it MUST NOT be null or the empty string ("").
A string that uniquely identifies this build. It SHOULD be reasonably
human-readable. It MUST follow this template:
$(PRODUCT_BRAND)/$(PRODUCT_NAME)/$(PRODUCT_DEVICE)/
$(TARGET_BOOTLOADER_BOARD_NAME):$(PLATFORM_VERSION)/
$(BUILD_ID)/$(BUILD_NUMBER):$(TARGET_BUILD_VARIANT)/
android.os.Build.FINGERPRINT
$(BUILD_VERSION_TAGS)
For example: acme/mydevicel/generic/generic:Donut/ERC77/
3359:userdebug/test-keys
The fingerprint MUST NOT include spaces. If other fields included in the
template above have spaces, they SHOULD be replaced with the ASCII
underscore ("_") character in the fingerprint.
A string that uniquely identifies the host the build was built on, in human
android.os.Build.HOST
readable format. There are no requirements on the specific format of this
field, except that it MUST NOT be null or the empty string ("").
An identifier chosen by the device implementer to refer to a specific
release, in human readable format. This field can by the same as
android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value
android.os.Build.ID
intended to be somewhat meaningful for end users. There are no
requirements on the specific format of this field, except that it MUST NOT
be null or the empty string ("").
A value chosen by the device implementer containing the name of the
device as known to the end user. This SHOULD be the same name
android.os.Build.MODEL
under which the device is marketed and sold to end users. There are no
requirements on the specific format of this field, except that it MUST NOT
be null or the empty string ("").
A value chosen by the device implementer containing the development
name or code name of the device. MUST be human-readable, but is not
android.os.Build.PRODUCT
necessarily intended for view by end users. There are no requirements
on the specific format of this field, except that it MUST NOT be null or the
empty string ("").
A comma-separated list of tags chosen by the device implementer that
further distinguish the build. For example, "unsigned,debug". This field
android.os.Build.TAGS
MUST NOT be null or the empty string (""), but a single tag (such as
"release") is fine.
android.os.Build.TIME
A value representing the timestamp of when the build occurred.
A value chosen by the device implementer specifying the runtime
configuration of the build. This field SHOULD have one of the values
android.os.Build.TYPE
corresponding to the three typical Android runtime configurations: "user",
"userdebug", or "eng".
A name or user ID of the user (or automated user) that generated the
android.os.Build.USER
build. There are no requirements on the specific format of this field,
except that it MUST NOT be null or the empty string ("").

3.2.3. Intent Compatibility
Android uses Intents to achieve loosely-coupled integration between applications. This section describes
requirements related to the Intent patterns that MUST be honored by device implementations. By
"honored", it is meant that the device implementer MUST provide an Android Activity, Service, or other
component that specifies a matching Intent filter and binds to and implements correct behavior for each
specified Intent pattern.
3.2.3.1. Core Application Intents
The Android upstream project defines a number of core applications, such as a phone dialer, calendar,
contacts book, music player, and so on. Device implementers MAY replace these applications with
alternative versions.
However, any such alternative versions MUST honor the same Intent patterns provided by the upstream
project. (For example, if a device contains an alternative music player, it must still honor the Intent pattern
issued by third-party applications to pick a song.) Device implementions MUST support all Intent patterns
listed in Appendix A.
3.2.3.2. Intent Overrides
As Android is an extensible platform, device implementers MUST allow each Intent pattern described in
Appendix A to be overridden by third-party applications. The upstream Android open source project
allows this by default; device implementers MUST NOT attach special privileges to system applications'
use of these Intent patterns, or prevent third-party applications from binding to and assuming control of
these patterns. This prohibition specifically includes disabling the "Chooser" user interface which allows
the user to select between multiple applications which all handle the same Intent pattern.
3.2.3.3. Intent Namespaces
Device implementers MUST NOT include any Android component that honors any new Intent or
Broadcast Intent patterns using an ACTION, CATEGORY, or other key string in the android.* namespace.
Device implementers MUST NOT include any Android components that honor any new Intent or
Broadcast Intent patterns using an ACTION, CATEGORY, or other key string in a package space
belonging to another organization. Device implementers MUST NOT alter or extend any of the Intent
patterns listed in Appendices A or B.
This prohibition is analogous to that specified for Java language classes in Section 3.6.

3.2.3.4. Broadcast Intents
Third-party applications rely on the platform to broadcast certain Intents to notify them of changes in the
hardware or software environment. Android-compatible devices MUST broadcast the public broadcast
Intents in response to appropriate system events. A list of required Broadcast Intents is provided in
Appendix B; however, note that the SDK may define additional broadcast intents, which MUST also be
honored.
3.3. Native API Compatibility
Managed code running in Dalvik can call into native code provided in the application .apk file as an ELF
.so file compiled for the appropriate device hardware architecture. Device implementations MUST include
support for code running in the managed environment to call into native code, using the standard Java
Native Interface (JNI) semantics. The following APIs must be available to native code:
• libc (C library)
• libm (math library)
• JNI interface
• libz (Zlib compression)
• liblog (Android logging)
• Minimal support for C++
• OpenGL ES 1.1
These libraries MUST be source-compatible (i.e. header compatible) and binary-compatible (for a given
processor architecture) with the versions provided in Bionic by the Android Open Source project. Since
the Bionic implementations are not fully compatible with other implementations such as the GNU C
library, device implementers SHOULD use the Android implementation. If device implementers use a
different implementation of these libraries, they must ensure header and binary compatibility.
Native code compatibility is challenging. For this reason, we wish to repeat that device implementers are
VERY strongly encouraged to use the upstream implementations of the libraries listed above, to help
ensure compatibility.
3.4. Web API Compatibility
Many developers and applications rely on the behavior of the android.webkit.WebView class [Resources,
11] for their user interfaces, so the WebView implementation must be compatible across Android
implementations. The Android Open Source implementation uses the WebKit rendering engine version to
implement the WebView.
Because it is not feasible to develop a comprehensive test suite for a web browser, device implementers
MUST use the specific upstream build of WebKit in the WebView implementation. Specifically:
• WebView MUST use the 528.5+ WebKit build from the upstream Android Open Source tree for
Android 1.6. This build includes a specific set of functionality and security fixes for the WebView.
• The user agent string reported by the WebView MUST be in this format:
Mozilla/5.0 (Linux; U; Android 1.6; <language>-<country>; <device
name>; Build/<build ID>) AppleWebKit/528.5+ (KHTML, like Gecko)
Version/3.1.2 Mobile Safari/525.20.1

◦ The "<device name>" string MUST be the same as the value for
android.os.Build.MODEL
◦ The "<build ID>" string MUST be the same as the value for android.os.Build.ID.
◦ The "<language>" and "<country>" strings SHOULD follow the usual conventions for
country code and language, and SHOULD refer to the current locale of the device at the
time of the request.
Implementations MAY ship a custom user agent string in the standalone Browser application. What's
more, the standalone Browser MAY be based on an alternate browser technology (such as Firefox,
Opera, etc.) However, even if an alternate Browser application is shipped, the WebView component
provided to third-party applications MUST be based on WebKit, as above.
The standalone Browser application SHOULD include support for Gears [Resources, 12] and MAY
include support for some or all of HTML5.
3.5. API Behavioral Compatibility
The behaviors of each of the API types (managed, soft, native, and web) must be consistent with the
preferred implementation of Android available from the Android Open Source Project.
Some specific areas of compatibility are:
• Devices MUST NOT change the behavior or meaning of a standard Intent
• Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system
component (such as Service, Activity, ContentProvider, etc.)
• Devices MUST NOT change the semantics of a particular permission
The above list is not comprehensive, and the onus is on device implementers to ensure behavioral
compatibility. For this reason, device implementers SHOULD use the source code available via the
Android Open Source Project where possible, rather than re-implement significant parts of the system.
The Compatibility Test Suite (CTS) tests significant portions of the platform for behavioral compatibility,
but not all. It is the responsibility of the implementer to ensure behavioral compatibility with the Android
Open Source Project.
3.6. API Namespaces
Android follows the package and class namespace conventions defined by the Java programming
language. To ensure compatibility with third-party applications, device implementers MUST NOT make
any prohibited modifications (see below) to these package namespaces:
• java.*
• javax.*
• sun.*
• android.*
• com.android.*
Prohibited modifications include:
• Device implementations MUST NOT modify the publicly exposed APIs on the Android platform
by changing any method or class signatures, or by removing classes or class fields.

• Device implementers MAY modify the underlying implementation of the APIs, but such
modifications MUST NOT impact the stated behavior and Java-language signature of any
publicly exposed APIs.
• Device implementers MUST NOT add any publicly exposed elements (such as classes or
interfaces, or fields or methods to existing classes or interfaces) to the APIs above.
A "publicly exposed element" is any construct which is not decorated with the "@hide" marker in the
upstream Android source code. In other words, device implementers MUST NOT expose new APIs or
alter existing APIs in the namespaces noted above. Device implementers MAY make internal-only
modifications, but those modifications MUST NOT be advertised or otherwise exposed to developers.
Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a namespace owned
by or referring to another organization. For instance, device implementers MUST NOT add APIs to the
com.google.* or similar namespace; only Google may do so. Similarly, Google MUST NOT add APIs to
other companies' namespaces.
If a device implementer proposes to improve one of the package namespaces above (such as by adding
useful new functionality to an existing API, or adding a new API), the implementer SHOULD visit
source.android.com and begin the process for contributing changes and code, according to the
information on that site.
Note that the restrictions above correspond to standard conventions for naming APIs in the Java
programming language; this section simply aims to reinforce those conventions and make them binding
through inclusion in this compatibility definition.
3.7. Virtual Machine Compatibility
A compatible Android device must support the full Dalvik Executable (DEX) bytecode specification and
Dalvik Virtual Machine semantics [Resources, 13].
3.8. User Interface Compatibility
The Android platform includes some developer APIs that allow developers to hook into the system user
interface. Device implementations MUST incorporate these standard UI APIs into custom user interfaces
they develop, as explained below.
3.8.1. Widgets
Android defines a component type and corresponding API and lifecycle that allows applications to expose
an "AppWidget" to the end user [Resources, 14]. The Android Open Source reference release includes a
Launcher application that includes user interface elements allowing the user to add, view, and remove
AppWidgets from the home screen.
Device implementers MAY substitute an alternative to the reference Launcher (i.e. home screen).
Alternative Launchers SHOULD include built-in support for AppWidgets, and expose user interface
elements to add, view, and remove AppWidgets directly within the Launcher. Alternative Launchers MAY
omit these user interface elements; however, if they are omitted, the device implementer MUST provide a
separate application accessible from the Launcher that allows users to add, view, and remove
AppWidgets.

3.8.2. Notifications
Android includes APIs that allow developers to notify users of notable events [Resources, 15]. Device
implementers MUST provide support for each class of notification so defined; specifically: sounds,
vibration, light and status bar.
Additionally, the implementation MUST correctly render and all resources (icons, sound files, etc.)
provided for in the APIs [Resources, 7], or in the Status Bar icon style guide [Resources, 16]. Device
implementers MAY provide an alternative user experience for notifications than that provided by the
reference Android Open Source implementation; however, such alternative notification systems MUST
support existing notification resources, as above.
3.8.3. Search
Android includes APIs [Resources, 17] that allow developers to incorporate search into their applications,
and expose their application's data into the global system search. Generally speaking, this functionality
consists of a single, system-wide user interface that allows users to enter queries, displays suggestions
as users type, and displays results. The Android APIs allow developers to reuse this interface to provide
search within their own apps, and allow developers to supply results to the common global search user
interface.
Device implementations MUST include a single, shared, system-wide search user interface capable of
real-time suggestions in response to user input. Device implementations MUST implement the APIs that
allow developers to reuse this user interface to provide search within their own applications.
Device implementations MUST implement the APIs that allow third-party applications to add suggestions
to the search box when it is run in global search mode. If no third-party applications are installed that
make use of this functionality, the default behavior SHOULD be to display web search engine results and
suggestions.
Device implementations MAY ship alternate search user interfaces, but SHOULD include a hard or soft
dedicated search button, that can be used at any time within any app to invoke the search framework,
with the behavior provided for in the API documentation.
3.8.4. Toasts
Applications can use the "Toast" API (defined in [Resources, 18]) to display short non-modal strings to the
end user, that disappear after a brief period of time. Device implementations MUST display Toasts from
applications to end users in some high-visibility manner.
4. Reference Software Compatibility
Device implementers MUST test implementation compatibility using the following open-source
applications:
• Calculator (included in SDK)
• Lunar Lander (included in SDK)
• ApiDemos (included in SDK)
• The "Apps for Android" applications [Resources, 19]
Each app above MUST launch and behave correctly on the implementation, for the implementation to be

considered compatible.
5. Application Packaging Compatibility
Device implementations MUST install and run Android ".apk" files as generated by the "aapt" tool
included in the official Android SDK [Resources, 20].
Devices implementations MUST NOT extend either the .apk, Android Manifest, or Dalvik bytecode
formats in such a way that would prevent those files from installing and running correctly on other
compatible devices. Device implementers SHOULD use the reference upstream implementation of Dalvik,
and the reference implementation's package management system.
6. Multimedia Compatibility
A compatible Android device must support the following multimedia codecs. All of these codecs are
provided as software implementations in the preferred Android implementation from the Android Open
Source Project [Resources, 4].
Please note that neither Google nor the Open Handset Alliance make any representation that these
codecs are unencumbered by third-party patents. Those intending to use this source code in hardware or
software products are advised that implementations of this code, including in open source software or
shareware, may require patent licenses from the relevant patent holders.
Audio
Name
Encoder Decoder Details
Files Supported
Mono/Stereo content in any
3GPP (.3gp) and
combination of standard bit rates
MPEG-4 (.mp4, .m4a)
AAC LC/LTP
X
up to 160 kbps and sampling rates files. No support for raw
between 8 to 48kHz
AAC (.aac)
Mono/Stereo content in any
3GPP (.3gp) and
HE-AACv1
combination of standard bit rates
MPEG-4 (.mp4, .m4a)
X
(AAC+)
up to 96 kbps and sampling rates files. No support for raw
between 8 to 48kHz
AAC (.aac)
Mono/Stereo content in any
HE-AACv2
3GPP (.3gp) and
combination of standard bit rates
(enhanced
MPEG-4 (.mp4, .m4a)
X
up to 96 kbps and sampling rates
AAC+)
files. No support for raw
between 8 to 48kHz
AAC (.aac)
AMR-NB
4.75 to 12.2 kbps sampled @
3GPP (.3gp) files
X
X
8kHz
AMR-WB
9 rates from 6.60 kbit/s to 23.85
-3GPP (.3gp) files
X
kbit/s sampled @ 16kHz
MP3
Mono/Stereo 8-320Kbps constant MP3 (.mp3) files
X
(CBR) or variable bit-rate (VBR)
Type 0 and 1 (.mid, .xmf,
MIDI Type 0 and 1. DLS Version 1
MIDI
X
.mxmf). Also RTTTL/RTX
and 2. XMF and Mobile XMF.
(.rtttl, .rtx), OTA (.ota),

Support for ringtone formats
and iMelody (.imy)
RTTTL/RTX, OTA, and iMelody
Ogg Vorbis
.ogg
X
8- and 16-bit linear PCM (rates up
PCM
X
WAVE
to limit of hardware)
Image
Files
Name
Encoder Decoder Details
Supported
JPEG
X
X
base+progressive
GIF
X
PNG
X
X
BMP
X
Video
Files
Name
Encoder Decoder Details
Supported
3GPP (.3gp)
H.263
X
X
files
3GPP (.3gp)
H.264
X
and MPEG-4
(.mp4) files
MPEG4
X
3GPP (.3gp) file
SP
7. Developer Tool Compatibility
Device implementations MUST support the Android Developer Tools provided in the Android SDK.
Specifically, Android-compatible devices MUST be compatible with:
• Android Debug Bridge or adb [Resources, 21]
Device implementations MUST support all adb functions as documented in the Android
SDK. The device-side adb daemon SHOULD be inactive by default, but there MUST be a user-
accessible mechanism to turn on the Android Debug Bridge.
• Dalvik Debug Monitor Service or ddms [Resources, 22]
Device implementations MUST support all ddms features as documented in the Android SDK.
As ddms uses adb, support for ddms SHOULD be inactive by default, but MUST be supported
whenever the user has activated the Android Debug Bridge, as above.

• Monkey [Resources, 23]
Device implementations MUST include the Monkey framework, and make it available for
applications to use.
8. Hardware Compatibility
Android is intended to support device implementers creating innovative form factors and configurations.
At the same time Android developers expect certain hardware, sensors and APIs across all Android
device. This section lists the hardware features that all Android 1.6 compatible devices must support. In
Android 1.6, the majority of hardware features (such as WiFi, compass, and accelerometer) are required.
If a device includes a particular hardware component that has a corresponding API for third-party
developers, the device implementation MUST implement that API as defined in the Android SDK
documentation.
8.1. Display
Android 1.6 includes facilities that perform certain automatic scaling and transformation operations under
some circumstances, to ensure that third-party applications run reasonably well on hardware
configurations for which they were not necessarily explicitly designed [Resources, 24]. Devices MUST
properly implement these behaviors, as detailed in this section.
8.1.1. Standard Display Configurations
This table lists the standard screen configurations considered compatible with Android:
Diagonal
Screen Size
Screen Density
Screen Type
Width (Pixels)
Height (Pixels)
Length Range
Group
Group
(inches)
QVGA
240
320
2.6 - 3.0
Small
Low
WQVGA
240
400
3.2 - 3.5
Normal
Low
FWQVGA
240
432
3.5 - 3.8
Normal
Low
HVGA
320
480
3.0 - 3.5
Normal
Medium
WVGA
480
800
3.3 - 4.0
Normal
High
FWVGA
480
854
3.5 - 4.0
Normal
High
WVGA
480
800
4.8 - 5.5
Large
Medium
FWVGA
480
854
5.0 - 5.8
Large
Medium
Device implementations corresponding to one of the standard configurations above MUST be configured
to report the indicated screen size to applications via the android.content.res.Configuration [Resources,
25] class.
Some .apk packages have manifests that do not identify them as supporting a specific density range.
When running such applications, the following constraints apply:

• Device implementations MUST interpret any resources that are present as defaulting to
"medium" (known as "mdpi" in the SDK documentation.)
• When operating on a "low" density screen, device implementations MUST scale down medium/
mdpi assets by a factor of 0.75.
• When operating on a "high" density screen, device implementations MUST scale up medium/
mdpi assets by a factor of 1.5.
• Device implementations MUST NOT scale assets within a density range, and MUST scale
assets by exactly these factors between density ranges.
8.1.2. Non-Standard Display Configurations
Display configurations that do not match one of the standard configurations listed in Section 8.2.1 require
additional consideration and work to be compatible. Device implementers MUST contact Android
Compatibility Team as provided for in Section 12 to obtain classifications for screen-size bucket, density,
and scaling factor. When provided with this information, device implementations MUST implement them
as specified.
Note that some display configurations (such as very large or very small screens, and some aspect ratios)
are fundamentally incompatible with Android 1.6; therefore device implementers are encouraged to
contact Android Compatibility Team as early as possible in the development process.
8.1.3. Display Metrics
Device implementations MUST report correct values for all display metrics defined in
android.util.DisplayMetrics [Resources, 26].
8.2. Keyboard
Device implementations:
• MUST include support for the Input Management Framework (which allows third party
developers to create Input Management Engines -- i.e. soft keyboard) as detailed at
developer.android.com
• MUST provide at least one soft keyboard implementation (regardless of whether a hard
keyboard is present)
• MAY include additional soft keyboard implementations
• MAY include a hardware keyboard
• MUST NOT include a hardware keyboard that does not match one of the formats specified
in android.content.res.Configuration [Resources, 25] (that is, QWERTY, or 12-key)
8.3. Non-touch Navigation
Device implementations:
• MAY omit non-touch navigation options (that is, may omit a trackball, 5-way directional pad, or
wheel)
• MUST report via android.content.res.Configuration [Resources, 25] the correct value for the
device's hardware

8.4. Screen Orientation
Compatible devices MUST support dynamic orientation by applications to either portrait or landscape
screen orientation. That is, the device must respect the application's request for a specific screen
orientation. Device implementations MAY select either portrait or landscape orientation as the default.
Devices MUST report the correct value for the device's current orientation, whenever queried via the
android.content.res.Configuration.orientation, android.view.Display.getOrientation(), or other APIs.
8.5. Touchscreen input
Device implementations:
• MUST have a touchscreen
• MAY have either capacative or resistive touchscreen
• MUST report the value of android.content.res.Configuration [Resources, 25] reflecting
corresponding to the type of the specific touchscreen on the device
8.6. USB
Device implementations:
• MUST implement a USB client, connectable to a USB host with a standard USB-A port
• MUST implement the Android Debug Bridge over USB (as described in Section 7)
• MUST implement a USB mass storage client for the removable/media storage is present in the
device
• SHOULD use the micro USB form factor on the device side
• SHOULD implement support for the USB Mass Storage specification (so that either removable
or fixed storage on the device can be accessed from a host PC)
• MAY include a non-standard port on the device side, but if so MUST ship with a cable capable of
connecting the custom pinout to standard USB-A port
8.7. Navigation keys
The Home, Menu and Back functions are essential to the Android navigation paradigm. Device
implementations MUST make these functions available to the user at all times, regardless of application
state. These functions SHOULD be implemented via dedicated buttons. They MAY be implemented
using software, gestures, touch panel, etc., but if so they MUST be always accessible and not obscure or
interfere with the available application display area.
Device implementers SHOULD also provide a dedicated search key. Device implementers MAY also
provide send and end keys for phone calls.
8.8. WiFi
Device implementations MUST support 802.11b and 802.11g, and MAY support 802.11a.

8.9. Camera
Device implementations MUST include a camera. The included camera:
• MUST have a resolution of at least 2 megapixels
• SHOULD have either hardware auto-focus, or software auto-focus implemented in the camera
driver (transparent to application software)
• MAY have fixed-focus or EDOF (extended depth of field) hardware
• MAY include a flash. If the Camera includes a flash, the flash lamp MUST NOT be lit while an
android.hardware.Camera.PreviewCallback instance has been registered on a Camera preview
surface.
Device implementations MUST implement the following behaviors for the camera-related APIs
[Resources, 27]:
1. If an application has never called android.hardware.Camera.Parameters.setPreviewFormat(int),
then the device MUST use android.hardware.PixelFormat.YCbCr_420_SP for preview data
provided to application callbacks.
2. If an application registers an android.hardware.Camera.PreviewCallback instance and the
system calls the onPreviewFrame() method when the preview format is YCbCr_420_SP, the
data in the byte[] passed into onPreviewFrame() must further be in the NV21 encoding format.
(This is the format used natively by the 7k hardware family.) That is, NV21 MUST be the default.
8.9.1. Non-Autofocus Cameras
If a device lacks an autofocus camera, the device implementer MUST meet the additional requirements in
this section. Device implementations MUST implement the full Camera API included in the Android 1.6
SDK documentation in some reasonable way, regardless of actual camera hardware's capabilities.
For Android 1.6, if the camera lacks auto-focus, the device implementation MUST adhere to the following:
1. The system MUST include a read-only system property named "ro.workaround.noautofocus"
with the value of "1". This value is intended to be used by applications such as Android Market to
selectively identify device capabilities, and will be replaced in a future version of Android with a
robust API.
2. If an application calls android.hardware.Camera.autoFocus(), the system MUST call the
onAutoFocus() callback method on any registered
android.hardware.Camera.AutoFocusCallback instances, even though no focusing actually
happened. This is to avoid having existing applications break by waiting forever for an autofocus
callback that will never come.
3. The call to the AutoFocusCallback.onAutoFocus() method MUST be triggered by the driver or
framework in a new event on the main framework Looper thread. That is, Camera.autoFocus()
MUST NOT directly call AutoFocusCallback.onAutoFocus() since this violates the Android
framework threading model and will break apps.
8.10. Accelerometer
Device implementations MUST include a 3-axis accelerometer and MUST be able to deliver events at at
least 50 Hz. The coordinate system used by the accelerometer MUST comply with the Android sensor
coordinate system as detailed in the Android APIs [Resources, 28].

8.11. Compass
Device implementations MUST include a 3-axis compass and MUST be able to deliver events at at least
10 Hz. The coordinate system used by the compass MUST comply with the Android sensor coordinate
system as defined in the Android API [Resources, 28].
8.12. GPS
Device implementations MUST include a GPS, and SHOULD include some form of "assisted GPS"
technique to minimize GPS lock-on time.
8.13. Telephony
Device implementations:
• MUST include either GSM or CDMA telephony
• MUST implement the appropriate APIs as detailed in the Android SDK documentation at
developer.android.com
Note that this requirement implies that non-phone devices are not compatible with Android 1.6; Android
1.6 devices MUST include telephony hardware. Please see Appendix C for information on non-phone
devices.
8.14. Volume controls
Android-compatible devices MUST include a mechanism to allow the user to increase and decrease the
audio volume. Device implementations MUST make these functions available to the user at all times,
regardless of application state. These functions MAY be implemented using physical hardware keys,
software, gestures, touch panel, etc., but they MUST be always accessible and not obscure or interfere
with the available application display area (see Display above).
When these buttons are used, the corresponding key events MUST be generated and sent to the
foreground application. If the event is not intercepted and sunk by the application then device
implementation MUST handle the event as a system volume control.
9. Performance Compatibility
One of the goals of the Android Compatibility Program is to ensure a consistent application experience for
consumers. Compatible implementations must ensure not only that applications simply run correctly on
the device, but that they do so with reasonable performance and overall good user experience.
Device implementations MUST meet the key performance metrics of an Android 1.6 compatible device,
as in the table below:
Metric
Performance Threshold
Comments

This is tested by CTS.
The following applications
The launch time is measured as the total time to
should launch within the
complete loading the default activity for the
Application
specified time.
application, including the time it takes to start the
Launch Time
Browser: less than 1300ms
Linux process, load the Android package into the
MMS/SMS: less than 700ms
Dalvik VM, and call onCreate.
AlarmClock: less than 650ms
Multiple applications will be
This is tested by CTS.
launched. Re-launching the
Simultaneous first application should
Applications
complete taking less than the
original launch time.
10. Security Model Compatibility
Device implementations MUST implement a security model consistent with the Android platform security
model as defined in Security and Permissions reference document in the APIs [Resources, 29] in the
Android developer documentation. Device implementations MUST support installation of self-signed
applications without requiring any additional permissions/certificates from any third parties/authorities.
Specifically, compatible devices MUST support the following security mechanisms:
10.1. Permissions
Device implementations MUST support the Android permissions model as defined in the Android
developer documentation [Resources, 9]. Specifically, implementations MUST enforce each permission
defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored.
Implementations MAY add additional permissions, provided the new permission ID strings are not in the
android.* namespace.
10.2. User and Process Isolation
Device implementations MUST support the Android application sandbox model, in which each application
runs as a unique Unix-style UID and in a separate process.
Device implementations MUST support running multiple applications as the same Linux user ID, provided
that the applications are properly signed and constructed, as defined in the Security and Permissions
reference [Resources, 29].

10.3. Filesystem Permissions
Device implementations MUST support the Android file access permissions model as defined in as
defined in the Security and Permissions reference [Resources, 29].
11. Compatibility Test Suite
Device implementations MUST pass the Android Compatibility Test Suite (CTS) [Resources, 3] available
from the Android Open Source Project, using the final shipping software on the device. Additionally,
device implementers SHOULD use the reference implementation in the Android Open Source tree as
much as possible, and MUST ensure compatibility in cases of ambiguity in CTS and for any
reimplementations of parts of the reference source code.
The CTS is designed to be run on an actual device. Like any software, the CTS may itself contain bugs.
The CTS will be versioned independently of this Compatibility Definition, and multiple revisions of the
CTS may be released for Android 1.6. However, such releases will only fix behavioral bugs in the CTS
tests and will not impose any new tests, behaviors or APIs for a given platform release.
12. Contact Us
You can contact the Android Compatibility Team at compatibility@android.com for clarifications related to
this Compatibiltiy Definition and to provide feedback on this Definition.

Appendix A: Required Application Intents
NOTE: this list is provisional, and will be updated in the future.
Application Actions
Schemes MIME Types
(none)
text/plain
http
text/html
Browser
android.intent.action.VIEW
https
application/xhtml+xml
application/
vnd.wap.xhtml+xml
(none)
android.intent.action.WEB_SEARCH
http
(none)
https
android.media.action.IMAGE_CAPTURE
android.media.action.STILL_IMAGE_CAMERA
Camera
android.media.action.VIDEO_CAMERA
android.media.action.VIDEO_CAPTURE
vnd.android.cursor.dir/
android.intent.action.VIEW
image
android.intent.action.GET_CONTENT
vnd.android.cursor.dir/
android.intent.action.PICK
video
android.intent.action.ATTACH_DATA
image/*
video/*
android.intent.action.VIEW
rtsp
video/mp4
video/3gp
android.intent.action.VIEW
http
video/3gpp
video/3gpp2
android.intent.action.DIAL
Phone /
android.intent.action.VIEW
tel
Contacts
android.intent.action.CALL
android.intent.action.DIAL
vnd.android.cursor.dir/
android.intent.action.VIEW
person

vnd.android.cursor.dir/
person
vnd.android.cursor.dir/
android.intent.action.PICK
phone
vnd.android.cursor.dir/
postal-address
vnd.android.cursor.item/
person
vnd.android.cursor.item/
android.intent.action.GET_CONTENT
phone
vnd.android.cursor.item/
postal-address
text/plain
Email
android.intent.action.SEND
image/*
video/*
android.intent.action.VIEW
mailto
android.intent.action.SENDTO
sms
android.intent.action.VIEW
smsto
SMS / MMS android.intent.action.SENDTO
mms
mmsto
audio/*
application/ogg
Music
android.intent.action.VIEW
file
application/x-ogg
application/itunes
audio/mp3
audio/x-mp3
android.intent.action.VIEW
http
audio/mpeg
audio/mp4
audio/mp4a-latm
vnd.android.cursor.dir/
artistalbum
vnd.android.cursor.dir/
album
vnd.android.cursor.dir/
android.intent.action.PICK
nowplaying
vnd.android.cursor.dir/
track
nd.android.cursor.dir/
playlist
vnd.android.cursor.dir/
video
media/*
audio/*
android.intent.action.GET_CONTENT
application/ogg
application/x-ogg
video/*

content
Package
android.intent.action.VIEW
file
Installer
package
file
android.intent.action.PACKAGE_INSTALL
http
https
android.intent.action.ALL_APPS
android.settings.SETTINGS
android.settings.WIRELESS_SETTINGS
android.settings.AIRPLANE_MODE_SETTINGS
android.settings.WIFI_SETTINGS
android.settings.APN_SETTINGS
android.settings.BLUETOOTH_SETTINGS
android.settings.DATE_SETTINGS
android.settings.LOCALE_SETTINGS
Settings
android.settings.INPUT_METHOD_SETTINGS
com.android.settings.SOUND_SETTINGS
com.android.settings.DISPLAY_SETTINGS
android.settings.SECURITY_SETTING
android.settings.LOCATION_SOURCE_SETTINGS
android.settings.INTERNAL_STORAGE_SETTINGS
android.settings.MEMORY_CARD_SETTINGS
android.intent.action.SET_WALLPAPER
Search
android.intent.action.SEARCH
query
android.intent.action.SEARCH_LONG_PRESS
Voice
android.intent.action.VOICE_COMMAND
Contacts Management
Intent Action
Description
Starts an Activity that lets the user pick
ATTACH_IMAGE
a contact to attach an image to.
Used
EXTRA_CREATE_DESCRIPTION
with SHOW_OR_CREATE_CONTACT to
specify an exact description to be

shown when prompting user about
creating a new contact.
Used
with SHOW_OR_CREATE_CONTACT to
EXTRA_FORCE_CREATE
force creating a new contact if no
matching contact found.
This is the intent that is fired when a
SEARCH_SUGGESTION_CLICKED
search suggestion is clicked on.
This is the intent that is fired when a
SEARCH_SUGGESTION_CREATE_CONTACT_CLICKED search suggestion for creating a
contact is clicked on.
This is the intent that is fired when a
SEARCH_SUGGESTION_DIAL_NUMBER_CLICKED
search suggestion for dialing a number
is clicked on.
Takes as input a data URI with a mailto:
SHOW_OR_CREATE_CONTACT
or tel: scheme.

Appendix B: Required Broadcast IntentsNOTE: this list is provisional, and will be
updated in the future.
Intent Action
Description
Broadcast Action: This is broadcast once, after the
ACTION_BOOT_COMPLETED
system has finished booting.
Broadcast Action: This is broadcast once, when a
ACTION_CALL_BUTTON
call is received.
Broadcast Action: The "Camera Button" was
ACTION_CAMERA_BUTTON
pressed.
Broadcast Action: The current
ACTION_CONFIGURATION_CHANGED
device Configuration (orientation, locale, etc) has
changed.
ACTION_DATE_CHANGED
Broadcast Action: The date has changed.
Broadcast Action: Indicates low memory condition
ACTION_DEVICE_STORAGE_LOW
on the device
Broadcast Action: Indicates low memory condition
ACTION_DEVICE_STORAGE_OK
on the device no longer exists
Broadcast Action: Wired Headset plugged in or
ACTION_HEADSET_PLUG
unplugged.
Broadcast Action: An input method has been
ACTION_INPUT_METHOD_CHANGED
changed.
Broadcast Action: External media was removed
ACTION_MEDIA_BAD_REMOVAL
from SD card slot, but mount point was not
unmounted.
Broadcast Action: The "Media Button" was
ACTION_MEDIA_BUTTON
pressed.
Broadcast Action: External media is present, and
being disk-checked The path to the mount point for
ACTION_MEDIA_CHECKING
the checking media is contained in the
Intent.mData field.
Broadcast Action: User has expressed the desire to
ACTION_MEDIA_EJECT
remove the external storage media.
Broadcast Action: External media is present and
ACTION_MEDIA_MOUNTED
mounted at its mount point.
Broadcast Action: External media is present, but is
using an incompatible fs (or is blank) The path to
ACTION_MEDIA_NOFS
the mount point for the checking media is
contained in the Intent.mData field.
Broadcast Action: External media has been
ACTION_MEDIA_REMOVED
removed.
Broadcast Action: The media scanner has finished
ACTION_MEDIA_SCANNER_FINISHED
scanning a directory.
Broadcast Action: Request the media scanner to
ACTION_MEDIA_SCANNER_SCAN_FILE
scan a file and add it to the media database.

Broadcast Action: The media scanner has started
ACTION_MEDIA_SCANNER_STARTED
scanning a directory.
Broadcast Action: External media is unmounted
ACTION_MEDIA_SHARED
because it is being shared via USB mass storage.
Broadcast Action: External media is present but
ACTION_MEDIA_UNMOUNTABLE
cannot be mounted.
Broadcast Action: External media is present, but
ACTION_MEDIA_UNMOUNTED
not mounted at its mount point.
Broadcast Action: An outgoing call is about to be
ACTION_NEW_OUTGOING_CALL
placed.
Broadcast Action: A new application package has
ACTION_PACKAGE_ADDED
been installed on the device.
Broadcast Action: An existing application package
ACTION_PACKAGE_CHANGED
has been changed (e.g. a component has been
enabled or disabled.
Broadcast Action: The user has cleared the data of
a package. This should be preceded
by ACTION_PACKAGE_RESTARTED, after which
ACTION_PACKAGE_DATA_CLEARED
all of its persistent data is erased and this
broadcast sent. Note that the cleared package
does not receive this broadcast. The data contains
the name of the package.
Broadcast Action: An existing application package
has been removed from the device. The data
ACTION_PACKAGE_REMOVED
contains the name of the package. The package
that is being installed does not receive this Intent.
Broadcast Action: A new version of an application
ACTION_PACKAGE_REPLACED
package has been installed, replacing an existing
version that was previously installed.
Broadcast Action: The user has restarted a
package, and all of its processes have been killed.
All runtime state associated with it (processes,
ACTION_PACKAGE_RESTARTED
alarms, notifications, etc) should be removed. Note
that the restarted package does not receive this
broadcast. The data contains the name of the
package.
Broadcast Action: Some content providers have
parts of their namespace where they publish new
ACTION_PROVIDER_CHANGED
events or items that the user may be especially
interested in.
ACTION_SCREEN_OFF
Broadcast Action: Sent after the screen turns off.
ACTION_SCREEN_ON
Broadcast Action: Sent after the screen turns on.
Broadcast Action: A user ID has been removed
ACTION_UID_REMOVED
from the system.
Broadcast Action: The device has entered USB
ACTION_UMS_CONNECTED
Mass Storage mode.

Broadcast Action: The device has exited USB
ACTION_UMS_DISCONNECTED
Mass Storage mode.
Broadcast Action: Sent when the user is present
ACTION_USER_PRESENT
after device wakes up (e.g when the keyguard is
gone).
Broadcast Action: The current system wallpaper
ACTION_WALLPAPER_CHANGED
has changed.
ACTION_TIME_CHANGED
Broadcast Action: The time was set.
ACTION_TIME_TICK
Broadcast Action: The current time has changed.
ACTION_TIMEZONE_CHANGED
Broadcast Action: The timezone has changed.
Broadcast Action: The charging state, or charge
ACTION_BATTERY_CHANGED
level of the battery has changed.
Broadcast Action: Indicates low battery condition
ACTION_BATTERY_LOW
on the device. This broadcast corresponds to the
"Low battery warning" system dialog.
Broadcast Action: Indicates the battery is now okay
after being low. This will be sent
ACTION_BATTERY_OKAY
after ACTION_BATTERY_LOW once the battery
has gone back up to an okay state.
Network State
Intent Action
Description
Broadcast intent action indicating that the
NETWORK_STATE_CHANGED_ACTION
state of Wi-Fi connectivity has changed.
Broadcast intent action indicating that the
RSSI_CHANGED_ACTION
RSSI (signal strength) has changed.
Broadcast intent action indicating that a
SUPPLICANT_STATE_CHANGED_ACTION
connection to the supplicant has been
established or lost.
Broadcast intent action indicating that Wi-Fi
WIFI_STATE_CHANGED_ACTION
has been enabled, disabled, enabling,
disabling, or unknown.
The network IDs of the configured networks
NETWORK_IDS_CHANGED_ACTION
could have changed.
Broadcast intent action indicating that the
ACTION_BACKGROUND_DATA_SETTING_CHANGED setting for background data usage has
changed values.
Broadcast intent indicating that a change in
CONNECTIVITY_ACTION
network connectivity has occurred.
Broadcast Action: The user has switched the
ACTION_AIRPLANE_MODE_CHANGED
phone into or out of Airplane Mode.

Appendix C: Future Considerations This appendix clarifies certain portions of this Android
1.6 Compatibility Definition, and in some cases discusses anticipated or planned changes intended for a
future version of the Android platform. This appendix is for informational and planning purposes only, and
is not part of the Compatibility Definition for Android 1.6.
1. Non-telephone Devices
Android 1.6 is intended exclusively for telephones; telephony functionality is not optional. Future versions
of the Android platform are expected to make telephony optional (and thus allow for non-phone Android
devices), but only phones are compatible with Android 1.6.
2. Bluetooth Compatibility
The Android 1.6 release of Android does not support Bluetooth APIs, so from a compatibility perspective
Bluetooth does not impose any considerations for this version of the platform. However, a future version
of Android will introduce Bluetooth APIs. At that point, supporting Bluetooth will become mandatory for
compatibility.
Consequently, we strongly recommend that Android 1.6 devices include Bluetooth, so that they will be
compatible with future versions of Android that require Bluetooth.
3. Required Hardware Components
All hardware components in Section 8 (including WiFi, magnetometer/compass, accelerometer, etc.) are
required and may not be omitted. Future versions of Android are expected to make some (but not all) of
these components optional, in tandem with corresponding tools for third-party developers to handle these
changes.
4. Sample Applications
The Compatibility Definition Document for a future version of Android will include a more extensive and
representative list of applications than the ones listed in Section 4, above. For Android 1.6, the
applications listed in Section 4 must be tested.
5. Touch Screens
Future versions of the Compatibility Definition may or may not allow for devices to omit touchscreens.
However, currently much of the Android framework implementation assumes the existence of a
touchscreen; omitting a touchscreen would break substantially all current third-party Android applications,
so in Android 1.6 a touchscreen is required for compatibility.

6. Performance
Future versions of CTS will also measure the CPU utilization and performance of the following
components of an implementation:
• 2D graphics
• 3D graphics
• Video playback
• Audio playback
• Bluetooth A2DP playback

Android 1.6 Compatibility Definition

Document Outline