The second day of Droidcon London — and they kept us going from 9am until 7pm with a full programme! As with the previous day, the keynotes were focussed on how Android is being used in non-phone devices — extending the rule of configurable software over fixed hardware.
I’d really like to add the slides to these notes — the Flurry presentation especially has loads of useful information that I didn’t catch. If any of the authors read this — please get in touch via twitter or leave a comment and I’ll add a link!
Future of Android - Vendscreen
Paresh Patel
- touchscreen device that fits as an extension on any vending machine
- accepts credit cards via swipe + tap to pay
- chip & pin coming later
- network connected — makes the machine smarter
- can cluster machines
- e.g. lots of machines in a hotel
- customers can get inventory from their phone
- energy management — can turn off some
- example: sold small artwork pieces in a vending machine
- people weren’t surprised
- prices didn’t have to be low
- people paid up to $99 by swiping their card
- right now running Android 2.3.4
- minor modifications:
- got rid of desktop
- added a recovery screen
Future of Android - Parrot Asteroid
Frederic Albinet
http://www.parrot.com/uk/products/hands-free-car-kits/parrot-asteroid
- parrot asteroid Android car radio
- classic & mini using Android 1.5(!!?!)
- tablet and smart devices using Android 2.3 (still old…)
- does voice recognition search for contacts and music
- music searches across connected device and also the internet radio stations and other sources
- parrot app market
- will be live from november
- can browse from PC or from device
- looking to extend to dynamic network between vehicles
- though this would depend on other cars having devices with the same protocol…
ADzero phone launch
- world’s first bamboo smartphone
- quad core device
- full HD screen
- bamboo feels really good to hold
- flash innovation: circle around the camera — works much better for macro
building songkick
Akshay Dashrath and Jamie McDonald, Novoda
- took 2 devs 3 months to build initial version
- agile process, two week iterations
- tools used:
- pivotal tracker
- github
- maven
- third party libs:
- ActionBarSherlock
- ViewPagerIndicator
- Novoda ImageLoader & Novocation
- NovodaTime — dealing with Joda Time problems
user experience design
- spent a lot of time finding pain points in initial install process using paper prototypes
- found out that putting buttons in the action bar were not found by users
- mocked up on an actual device to see how it felt
- can set a custom notification light colour (works well with branding!)
- styled login web view to look like rest of app
- first launch experience:
- had a scan screen with an OpenGL animation to keep the user entertained while the initial artist information is found
- used external apps that expose content providers
- google music — got artist names using a projection and flexjson to push it to songkick server
- last.fm
caching & location
- used novoda’s novocation location library
- used Jackson mixture of streaming & tree model to avoid memory issues
- data from web calls loaded into database, then database loaded into views with cursor loaders
- detachable result receiver — google IO 2011 app
- lets you deal with rotating views and re-attaching the new activity to the old cursor loader
- all visited content cached using Reto Meier’s Big Cookie approach (see Making Good Apps Great)
- “Just Added” concerts sync in the background
- if offline, then shows a transparent banner at the bottom of the page
- send out a sticky broadcast if an online query fails
- broadcast cleared if the app gets a good response
- Big Cookie caching can build up too much data
- data removed on a daily basis by removing old data — e.g. past concerts, etc
testing
- manual QA for most stuff
- automated tests were more for stress testing
- also did observational user testing (one-way mirror room)
- put UI options in a debug menu so could easily do A/B testing
- build machine runs instrumentation tests on however many devices are plugged into it
- used Eclipse Memory Analysis Tool to check memory allocation
- used to fix large back stack activity
- enabled StrictMode to deal with issues with Google Analytics & Joda Time
- Joda Time used the UI thread for DST settings (can be fixed — see Stack Overflow)
featured!
- got featured in Play
- installs went 400 / day -> 20,000 / day!
soundcloud audio in Android
Jan Berkel and Jon Schmidt, SoundCloud
playback
- Java MediaPlayer talks to C layer MediaPlayerService
- check out the C source code to see what’s going on
- underneath this uses PacketVideo OpenCore up to 2.2, then Google Stagefright
- shouldn’t have to care about underlying implementation but if you’re doing something complicated you do…
- OpenCore
- mature, stable but limited
- seekTo doesn’t work in streams
- Stagefright (default from 2.2 and beyond)
- fixes seeking
- but not available in all devices…
- when launched shortly after 2.3 released decided to support 2.1+ so that could cover 75-80% of devices
- to find out which mediaplayer, tried to read
/system/build.prop - however, some phones had both frameworks!
- one for streaming and one for encoding…
- playing locally would behave differently than streaming from a server
- so to actually find out, connect the MediaPlayer to a local socket and read the user agent on the other end…
- built a StreamProxy local server
- could cache and fetch chunks from CDN
- MediaPlayer then talks to proxy
- inspired by NPR android app
- but still no control over buffering (may want to alter it depending on network conditions)
- different versions of Android behave differently
- ICS has a huge buffer so takes ages before it starts playing…
- bundled Android HttpClient is broken (it’s an old snapshot, not a proper release)
- have to catch NPE from execute!
- recommended to use standard Java URLConnection
- bundled HttpClient has now been deprecated
recording
- live encoding options on earlier Android versions — just AMR AB
- only good for voice
- narrow range, low quality — sounds like a phone call
- instead recorded in PCM and used 3rd party lib to encode it before uploading
- chose ogg vorbis
- good for licenses
- java port is slow (and incomplete)
- would take 4x length of audio to encode!!
- from 2.3.3 Android introduced AAC encoding
- new requirements involved getting at the actual audio data — simple editing, resuming record
- had to write own native layer for codecs and audio processing (Java too slow)
- used C-based Vorbis Encoder & Decoder with a thin wrapper
- also added a native amplitude analyzer
- tried to avoid sending data back and forth too often
- but… now had to deal with CPU flavours
- armv5 on older devices has no floating point support
- have to build native pieces for various architectures (armv7, mips, x86)
- older devices fall back to old-style encode later style
- Jelly Bean has new media encoding APIs
- will be useful in the future…
- some sony devices have a patched media framework that behaves differently…
bug detection
- robolectric
- bugsense crash reports
- get a load of devices and get people to use them
The fly-in app menu for designer and developer
Cyril Mottier @cyrilmottier
- watch out for activity back stack
- recommended to only use fly-in menu at root level
- but still want the back button to exit the app without going via the fly-in menu
- libraries (all on github)
- android-undergarment
- slidingmenu
- android-menudrawer
- don’t slide the actionbar
- you’d need a custom actionbar…
- or create your own: need a custom view group & view
- see “making of prixing”
- make the slid out activity inactive
- click on it to make it visible again
- may need to think about right-to-left languages having right-sliding menus
Who needs thumbs? Android Instrumentation and Reverse Engineering
David Teitelbaum http://blog.apkudo.com/
I only caught the very end of this, but it looked like it could be a really useful talk — worth chasing down the slides
Android and Arduino
Fei Manheche, Robobo
- 3 steps:
- build basic circuit & test it from PC (use serial monitor via direct connection or Bluetooth)
- build basic arduino software to set it up to be controlled from Android
- build Android app to talk to Arduino
- bluetooth modules available for £6-10
- use amarino library to simplify bluetooth between android and arduino
- can also use amarino app to test basic bluetooth connection
- don’t send too much data to the arduino at once (unless you write buffering serial code on the arduino…)
Memory Analyzer: avoiding memory leaks
Felipe Ferraz, CESAR
- each process on Android has its own Dalvik VM
- the Zygote process is forked for each app
- it already has common libraries mapped into it, so they’re shared as read-only between all apps
- use adb to make a heap dump (
kill -10 <pid>)
- or use Eclipse…
- useful to create multiple heap snapshots to tell story of memory leak
- http://www.eclipse.org/mat/
- make sure to null Callables inside Images
Using Ubuntu to develop cloud-connected android apps
Victor Palau, Ubuntu
- juju: https://juju.ubuntu.com/
- orchestrates groups of servers deployed to cloud systems
- can deploy a local instance or to Amazon ECS (or any other OpenStack compatible service)
- local deployment uses zookeeper to set up containers on a single machine
Mobile Analytics - taking your Android app to the next level
Simon Podd, Director of Sales, Flurry EMEA
- according to EMF there are 2Bn “affluent adults” in the world
- 17% of time spent in Android apps is in Europe
- time spent in apps is increasing month by month (94mins/day in Dec 2011)
- social networking category is growing fast (equal to games in Q1 2012)
- Flurry tracking 220K apps across 660m devices
- iPad makes up 88% of top 3 tablet sessions
- of the top 20 Android devices by worldwide sessions (May 2012), the top 3 are:
- Galaxy SII
- Galaxy Ace
- Moto Defy
- worldwide 2011 app revenue (iOS & Android):
- 52% in-app purchases
- 24% mobile advertising
- 25% app sales
- advertising revenue (from Flurry’s ad slots):
- iOS $6-10 eCPM
- Android $20-30 eCPM
gaming category stats
- ages 13-34 spend most time in apps
- 18-24 & 25-34 about even
- fairly even gender split
- more money spent by 25-34yo men (29%)
- average transaction sizes fairly constant across ages, and higher than you might think:
- M: $15.60
- F: $11.90
- customers download on average 50-85 apps during a device lifetime
- but they only use 5-10 apps a day
- there’s an app discovery issue on the device
flurry tracking
- can use ranges for event parameters…
Applying lean principles to enterprise mobile development
Dave Slocombe @daveslocombe — Head of Mobile Channel, lastminute.com
- product scorecards
- 5 or 6 key goals for the year
- see Marty Cagan, SVG
- keep time to release short
- don’t miss the opportunity to innovate
- avoid big bang releases
- essentials: co-location & cross-functional
generating and managing ideas
- ideas should come from all sides of the business
- need to have a massive bucket of ideas
- make them visible so you can choose amongst them
- great for managing HiPPos (highest paid persons)
- they can see that their idea is on the board
- doesn’t mean that you have to work on them!
- prioritise ideas
- use the product scorecard
selecting ideas for development
- UX team does customer insights
- qualitative: what problems are we solving? is there a market?
- quantitative: talking to data analysts
- looking for strong signals
- product owner reviews customer insights
- UX team create designs in iterations, increasing fidelity as they go
- want to be able to ditch bad ideas before spending too much time on them
- try guerilla testing: take it to someone in a coffee shop and ask them what they think
- get marketing and devs involved as well
- get UX ideas out without using developer time
- use axure or similar
- have an internal site of proposed designs
- available to exec team
- play back early stage designs to other teams, like finance and supply
- surface problems and feedback early
- if ideas are generated, they can go back onto the ideas board (don’t deal with them right now)
development processes
- retrospectives
- done every two weeks
- if you leave it longer, the issues get bigger and harder to solve
- more frequent = smaller, easier to fix issues
- e.g. found that they needed a “design issues” wall
- edge cases found missing by the designer, not captured
- introduced “creative coding” — designer + developer pairing, making a first pass of the UI
- brings designers into what’s possible on mobile
- helps devs understand value of brand & aims of user experience
- Dave was originally a skeptic of pairing, but converted:
- sharing knowledge
- repeatability, consistency
- drives out “hero developer” mentality
testing & releasing
- “release process is the metronome that drives progress”
- continuous deployment
- every check-in should be deployable
- repeatable consistent environments
- currently 12mins to deploy to production
- devices are tiered for testing:
- automated tests, max experience, manual test
- automated tests, optimum, limited manual
- observe trending, monthly testing, graceful fallback
- just pushed iOS 3 down a level
- looking at webdriver to generate PDFs for visual check
tying it together
- showcase every two weeks
- include other departments
- no roadmap items, just value added in the last two weeks
- focus on what your customers say, not what the industry says is cool
- apps vs web — choose from your own analytics
- e.g. for travel, 3x more likely to book on web
- stats:
- seen 10% month on month growth in Android, compared to iOS
- ensure product always gives tech team 20% tech debt time
Replacing the Android emulator
Daniel Fages, Genymobile
- built on top of android-x86
- has an emulated WiredSSID wi-fi connection
- can use OpenGL 2.0 using hardware
- works really well - can emulate Angry Birds
- just added injecting sensors from attached Android device (accelerometer, etc)
- currently working on management tool and other features
- looking for feedback on next features
- network
- also can install VM on other people’s machines without having to worry about SDK
- will be working to integrate with Jenkins
- could be great for creating a snapshot when something goes wrong
- not working:
- multitouch
- NFC, Bluetooth
- GSM pieces: SMS & voice
Developing accessible apps for Android
Gary Readfern-Grey, RNIB
- many people are relying on apps as the only way to do crucial things in life
- talkback comes with Jelly Bean
- problem:
- icon-based buttons don’t have proper audio labels (“icon 39”, “icon 19”) so can’t find what is on the screen
- watch out for “jump back button button”
- accessibility came in on Donut 1.6
- relied on physical keyboard and trackball
- touching the screen behaved as normal and gave no feedback
- Talkback and Eyes-free-keyboard added more recently
- eyes-free added in Gingerbread
- ICS brought in explore-by-touch
- Jelly Bean brings in gestures:
- moving focus
- back, home, recent apps
- notification shade
- WebView is harder
- Jelly Bean & ICS have an additional “allow web accessibility” checkbox
testing your app
- download talkback from google play
- Jelly Bean has it installed (at least on Nexus 7)
- settings / accessibility / turn on Talkback
- check that views are focusable and have content descriptions
- custom views need hover events
documentation
- Google I/O 2012 making android apps accessible on youtube
- developer.android.com: making applications accessible
- android 4.1 accessibility APIs
top things to do:
- add content descriptions to your widget
- can do in XML layout using android:contentDescription attribute
- or use setContentDescription
- latest linter should check for this
- make sure you can get to all elements of the app through a keyboard
- will also help for Google TV
- don’t depend on colour alone…
- e.g. “correct the field that’s coloured red”
- test it! try out Talkback
- RNIB Innovation can help you
- RNIB offer paid consultancy
- if they’re doing something that RNIB really want and aren’t in a position to pay, then they could offer free help too
- innovation@rnib.org.uk
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