What's New in Jelly Bean

Big Android BBQ 2012

What's New in
Jelly Bean
Copyright © 2012CommonsWare, LLC

Project Butter
● UI Updates @ 60 frames/second
● Objective: smoother UI updates
– Especially animations
● Transparent to developers
– No code changes to “opt into” Butter effects
● Google I/O 2012: “For Butter or Worse”


Project Butter Ramifications
● Only ~16ms Per Frame
– Your code on the main application thread
– Framework code
– Other interruptions (e.g., background process)
● Net: Get Off the Main Application Thread!
– Anything taking more than a few milliseconds
needs to move to background thread or be
executed incrementally

Project Butter & Choreographer
06-29 23:11:17.796: I/Choreographer(691): Skipped 647 frames!
The application may be doing too much work on its main thread.

● Information Message in LogCat
– “Skipped N frames” * 16ms = amount of time
you took on main application thread
– The more frames skipped, the more likely it is
the user will notice
● UI frozen and not responsive
● Animation/scrolling hiccups

Expandable Notifications
● Alternative Visual Representation
– Taller, room for more text or image
– Optional action buttons
● When Appears
– When at top of drawer
– User expansion via
two-finger swipe gesture


● Styles
– BigTextStyle: larger amount of prose
– BigListStyle: subject lines, news headlines,
etc.
– BigPictureStyle: shared photos, etc.
● Actions
– Up to three
– Immediate operations with fewer clicks

● Creating Them
– Use Notification.Builder or
NotificationCompat.Builder
– Create regular Notification
– Wrap in a “big” style Notification
● Wrapper “inherits” values from wrapped one (e.g.,
timestamp)
● Android uses one or the other based upon
circumstances

READ_LOGS Regression
● Before
– No API for reading LogCat contents
– SDK apps could hold READ_LOGS and use
undocumented means instead
● Now
– No API for reading LogCat contents
– Only firmware apps can hold READ_LOGS
– Default: can only read own messages

READ_LOGS Regression
● Effects
– Cannot report system error messages via ACRA
and kin
– Limits native IDEs (AIDE, etc.), as they cannot
show messages from apps they create
● Reasons
– Privacy: too much crap getting logged
– Security: reduce blocking attacks

READ_EXTERNAL_STORAGE
● New Permission
– Required if you are reading from external
storage and do not already hold
WRITE_EXTERNAL_STORAGE
● Not Enforced By Default
– Jelly Bean: enabled in Developer Options
– K+: possibly enabled by default


READ_EXTERNAL_STORAGE
● Reason: Privacy
– Addressing the “any app has access to our
photos” complaint
● Warning: No Grandfathering
– No indication that apps with low
targetSdkVersion will be granted this
permission by default
– Users can toggle this on now

Other Notable Changes
● Full Bi-Directional Text Support
(no, really, honest, we got it this time!)
– Also custom keymaps, to surface other
characters more easily
● Fully-Resizable App Widgets
– And your code gets to find out, too!
– Also get GridLayout and ViewStub support
● Improved Accessibility

● Android Beam
– Bulk content transfer, kicked off by NFC,
completed by Bluetooth
● Google Cloud Messaging
– Permanent replacement for Labs' C2DM
– Various improvements, still free


● More Changes for Task Navigation
● More Options for Lights Out/Full Screen
● Service Discovery (WiFi, WiFi Direct)
● Audio Improvements (e.g., codec
enumeration)
● Better WebView
● Etc.

Jelly Bean/API Level 16 Uptake
● Presently: 1.8% (as of October 1, 2012)
● Short-Term Growth
– Upgrades from manufacturers
– Gingerbread contract expirations
– Holiday season sales
● Predictions
– 10% by February 1, 2013
– 25% by June 1, 2013

What's New in Jelly Bean

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