Android 2.1 (Eclair MR1) SDK is out

One week after releasing the Android Nexus One phone to the public, Google has released the software development kit (SDK) that allows third-party developers to write applications for the phone. Android 2.1 has several new features including:

• Live Wallpapers
• Support for HTML5 video, geolocation, and web storage in WebViews
• New APIs for determining cellular signal strength
• New methods for Android views such as automatic view flippers and opaque views
• Support for a voice recognition audio source and camera-facing microphone
• New features that an app can optionally require before installing, including a multi-touch screen

Version 2.1 is also referred to as Eclair Maintenance Release 1 (MR1), or API level 7 to programmers. In all, 2.1 has 118 API changes, which is approximately a 0.48% difference compared to the previous version.

Availability

Android 2.1 is currently shipping on the HTC Nexus One. The Motorola Droid (Sholes) sold by Verizon is currently at 2.0.1 but users should expect an over the air update "soon" (which could mean anything from 2 weeks to 2 months). As of this writing, all other Android devices (about 80% of the market, according to Google) are running version 1.5 or 1.6:

Source: Google market data collected during the two weeks ending on 1/4/2010

Eventually 2.0.1 will go away, replaced by 2.1 just as 2.0 was replaced by 2.0.1. If current trends continue, we predict that 2.0.1/2.1 will achieve a 25% market share by February, and 50% by the end of the year.

Note that all programs written using the 1.5/1.6 APIs should work on newer devices, but you should test your apps on all targeted versions and screen sizes just to make sure. Programs written to require the 2.0.1/2.1 APIs will not work on older devices.