Android 4.2 Compatibility Definition

Revision 2
Last updated: Feb 17, 2013

Copyright © 2012, Google Inc. All rights reserved.
[email protected]

Table of Contents

1. Introduction

This document enumerates the requirements that must be met in order for devices to be compatible with Android 4.2.

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, 1].

As used in this document, a "device implementer" or "implementer" is a person or organization developing a hardware/software solution running Android 4.2. A "device implementation" or "implementation" is the hardware/software solution so developed.

To be considered compatible with Android 4.2, device implementations MUST meet the requirements presented in this Compatibility Definition, including any documents incorporated via reference.

Where this definition or the software tests described in Section 10 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, 3] is both the reference and preferred implementation of Android. Device implementers are strongly encouraged to base their implementations to the greatest extent possible 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 software 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. Finally, note that certain component substitutions and modifications are explicitly forbidden by this document.

2. Resources

1. IETF RFC2119 Requirement Levels: http://www.ietf.org/rfc/rfc2119.txt
2. Android Compatibility Program Overview: http://source.android.com/docs/compatibility/index.html
3. Android Open Source Project: http://source.android.com/
4. API definitions and documentation: http://developer.android.com/reference/packages.html
5. Android Permissions reference: http://developer.android.com/reference/android/Manifest.permission.html
6. android.os.Build reference: http://developer.android.com/reference/android/os/Build.html
7. Android 4.2 allowed version strings: http://source.android.com/docs/compatibility/4.2/versions.html
8. Renderscript: http://developer.android.com/guide/topics/graphics/renderscript.html
9. Hardware Acceleration: http://developer.android.com/guide/topics/graphics/hardware-accel.html
10. android.webkit.WebView class: http://developer.android.com/reference/android/webkit/WebView.html
11. HTML5: http://www.whatwg.org/specs/web-apps/current-work/multipage/
12. HTML5 offline capabilities: http://dev.w3.org/html5/spec/Overview.html#offline
13. HTML5 video tag: http://dev.w3.org/html5/spec/Overview.html#video
14. HTML5/W3C geolocation API: http://www.w3.org/TR/geolocation-API/
15. HTML5/W3C webdatabase API: http://www.w3.org/TR/webdatabase/
16. HTML5/W3C IndexedDB API: http://www.w3.org/TR/IndexedDB/
17. Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs
18. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
19. Notifications: http://developer.android.com/guide/topics/ui/notifiers/notifications.html
20. Application Resources: http://code.google.com/android/reference/available-resources.html
21. Status Bar icon style guide: http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html
22. Search Manager: http://developer.android.com/reference/android/app/SearchManager.html
23. Toasts: http://developer.android.com/reference/android/widget/Toast.html
24. Themes: http://developer.android.com/guide/topics/ui/themes.html
25. R.style class: http://developer.android.com/reference/android/R.style.html
26. Live Wallpapers: https://android-developers.googleblog.com/2010/02/live-wallpapers.html
27. Android Device Administration: http://developer.android.com/guide/topics/admin/device-admin.html
28. DevicePolicyManager reference: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html
29. Android Accessibility Service APIs: http://developer.android.com/reference/android/accessibilityservice/package-summary.html
30. Android Accessibility APIs: http://developer.android.com/reference/android/view/accessibility/package-summary.html
31. Eyes Free project: http://code.google.com/p/eyes-free
32. Text-To-Speech APIs: http://developer.android.com/reference/android/speech/tts/package-summary.html
33. Reference tool documentation (for adb, aapt, ddms, systrace): http://developer.android.com/guide/developing/tools/index.html
34. Android apk file description: http://developer.android.com/guide/topics/fundamentals.html
35. Manifest files: http://developer.android.com/guide/topics/manifest/manifest-intro.html
36. Monkey testing tool: https://developer.android.com/studio/test/other-testing-tools/monkey
37. Android android.content.pm.PackageManager class and Hardware Features List: http://developer.android.com/reference/android/content/pm/PackageManager.html
38. Supporting Multiple Screens: http://developer.android.com/guide/practices/screens_support.html
39. android.util.DisplayMetrics: http://developer.android.com/reference/android/util/DisplayMetrics.html
40. android.content.res.Configuration: http://developer.android.com/reference/android/content/res/Configuration.html
41. android.hardware.SensorEvent: http://developer.android.com/reference/android/hardware/SensorEvent.html
42. Bluetooth API: http://developer.android.com/reference/android/bluetooth/package-summary.html
43. NDEF Push Protocol: http://source.android.com/docs/compatibility/ndef-push-protocol.pdf
44. MIFARE MF1S503X: http://www.nxp.com/documents/data_sheet/MF1S503x.pdf
45. MIFARE MF1S703X: http://www.nxp.com/documents/data_sheet/MF1S703x.pdf
46. MIFARE MF0ICU1: http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf
47. MIFARE MF0ICU2: http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf
48. MIFARE AN130511: http://www.nxp.com/documents/application_note/AN130511.pdf
49. MIFARE AN130411: http://www.nxp.com/documents/application_note/AN130411.pdf
50. Camera orientation API: http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)
51. Camera: http://developer.android.com/reference/android/hardware/Camera.html
52. Android Open Accessories: http://developer.android.com/guide/topics/usb/accessory.html
53. USB Host API: http://developer.android.com/guide/topics/usb/host.html
54. Android Security and Permissions reference: http://developer.android.com/guide/topics/security/security.html
55. Apps for Android: http://code.google.com/p/apps-for-android
56. Android DownloadManager: http://developer.android.com/reference/android/app/DownloadManager.html
57. Android File Transfer: http://www.android.com/filetransfer
58. Android Media Formats: http://developer.android.com/guide/appendix/media-formats.html
59. HTTP Live Streaming Draft Protocol: http://tools.ietf.org/html/draft-pantos-http-live-streaming-03
60. NFC Connection Handover: http://www.nfc-forum.org/specs/spec_list/#conn_handover
61. Bluetooth Secure Simple Pairing Using NFC: http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf
62. Wifi Multicast API: http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html
63. Action Assist: http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST
64. USB Charging Specification: http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf
65. Android Beam: http://developer.android.com/guide/topics/nfc/nfc.html
66. Android USB Audio: http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO
67. Android NFC Sharing Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS
68. Wifi Direct (Wifi P2P): http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html
69. Lock and Home Screen Widget: http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html
70. UserManager reference: http://developer.android.com/reference/android/os/UserManager.html
71. External Storage reference: https://source.android.com/docs/core/storage
72. External Storage APIs: http://developer.android.com/reference/android/os/Environment.html
73. SMS Short Code: http://en.wikipedia.org/wiki/Short_code
74. Media Remote Control Client: http://developer.android.com/reference/android/media/RemoteControlClient.html
75. Display Manager: http://developer.android.com/reference/android/hardware/display/DisplayManager.html
76. Dreams: http://developer.android.com/reference/android/service/dreams/DreamService.html
77. Android Application Development-Related Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS

Many of these resources are derived directly or indirectly from the Android 4.2 SDK, and will be functionally identical to the information in that SDK's documentation. In any cases where this Compatibility Definition or the Compatibility Test Suite 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

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 4.2 SDK [Resources, 4].

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.

This Compatibility Definition permits some types of hardware for which Android includes APIs to be omitted by device implementations. In such cases, the APIs MUST still be present and behave in a reasonable way. See Section 7 for specific requirements for this scenario.

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.

3.2.1. Permissions

Device implementers MUST support and enforce all permission constants as documented by the Permission reference page [Resources, 5]. Note that Section 10 lists additional 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, 6] 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.