The Android 4.2 (Jelly Bean) SDK platform (API level 17) brings the following key improvements:
Performance – Renderscript computation can be run directly in the GPU on the Nexus 10. This is a first since Exynos 5250 is the first ARM processor capable of supporting GPGPU (via Mali-T604 GPU). See the chart of the right showing results between CPU and CPU+GPU computation of some multimedia benchmarks.
- Lock screen widgets – Users can now place interactive lock screen widgets directly on their device lock screens. This only requires a small update to adapt existing widgets to run on the lock screen.
- Daydream – An interactive screensaver mode that can be used when the device is charging or docked to a desk dock.
- Better external displays support – Android 4.2 introduces platform support for multiple displays attached to an Android device.
- Native RTL Support – Android 4.2 includes native RTL support for bi-directional languages such as Arabic, Hebrew, and Persian, including layout mirroring.
- Font and character optimizations – There is a number of font and character optimizations for Korean, Japanese, Indic, Thai, Arabic and Hebrew writing systems.
You can download the Android 4.2 Platform SDK from the Android SDK Manager. For more details, you can check out the Android 4.2 platform and read the API overview. If you are more interested in the user perspective, check out “New Features in Android 4.2 Jelly Bean“.
Android 4.2 source is also available in AOSP. Assuming your build environment is already setup, and repo already installed. If not:
curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo
chmod a+x ~/bin/repo
repo init -u https://android.googlesource.com/platform/manifest -b android-4.2_r1
Jean-Baptiste Query explains that “Nexus 10 is now the best platform for AOSP work on 4.2, as everything except the GPU code is open source, and the only proprietary binaries besides the GPU libraries are firmware files that get loaded into the various peripheral chips. No flagship device so far has been so open, and no flagship device so far has had that level of AOSP support at launch. ”
Android 4.2 (JOP40C) factory images for Nexus 10, Nexus 7 (Wi-Fi & 3G), Nexus 4 and Galaxy Nexus can be downloaded from https://developers.google.com/android/nexus/images
Android 4.2 binary drivers for Nexus 10, Nexus 7 (Wi-Fi only) and Galaxy Nexus are available for download at https://developers.google.com/android/nexus/drivers. Please note that there is nothing for LG Nexus 4 in the source code, or the binary drivers download section.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.