iOSDev UK: Design Considerations for Educational Apps

Fraser Speirs, Head of Computing & IT, Cedars School of Excellence, @fraserspeirs

http://speirs.org

• last year gave every child an iPad
  • only 100 pupils
  • had 220 people come to visit the school…
• when you give people the internet the whole time, you sometimes get unexpected results
  • Fraser showed a slide of coursework on cell nuclei, decorated with a background showing the Statue of Darth Liberty
• sitting around iPads — everybody faces each other rather than all facing the screen at the front
• avoiding the ceremonial computer lab — moving to casual computing
• beautiful artwork created by kids on iPads, within a month of receiving them
• it’s not just the iPads, it’s the 1:1 — the 1:1 is more important
• Fraser’s daughter is 4.5 — just started school
  • will graduate from university in Summer 2029
  • “we are already teaching the citizens of the 22nd century”
• looking at investment as kids’ chairs & tables
  • not as a guarantee that scores will go up

Do’s and Don’ts for apps in schools

• don’t assume the internet works correctly
  • schools change what internet is available through frequent policy changes
  • youtube is often turned off
• teaching fashions come and go regularly
• in-app purchase doesn’t work in schools
  • central purchasing or gifting
  • e.g. PCalc has a full version that can be purchased at once
• don’t assume your users can (will) read
  • use conventions wisely (keep the back button in top left corner)
• use push notifications sparingly
  • no good advertising to kids in school — they don’t have the app store password anyway
• watch out for number of devices nearby
  • could be 20-30 devices around
  • infrastructure may cope, but leave room in your UI
• limit or prevent app store interactions
  • no good in schools
  • confuses kids; annoying for teachers
  • that goes for “review me now” too
• teachers need access to content
  • support the photos app
• don’t promote facebook
  • facebook can be a major source of anxiety for many children
• watch out for shaking gestures — not good for
• don’t use bad language (and try to avoid double-entendres and local slang too). Some examples:
  • Rasterbator
  • Procreate
  • Little Snapper
  • hardware growler
  • mental case
  • FlashToPass
  • http://gojobby.com
• be very careful with user data — especially with location
• talk to teachers and test with actual children
  • Fraser’s school does not have the scale to be a beta tester…
• watch out for different curricula in different countries
• walk through guide in the app
  • see toontastic
• kids can use loads of apps to edit graphics, passing the image through the photos app
• use sharing effectively
  • use “Open In…”
  • avoid huge sharing option lists
• show proof of completion
• avoid (penalise) random hits
• structure + headroom = creativity
  • app idea: make toontastic for creative writing
• show user activity
  • e.g. Brushes lets you record all your strokes and play them back as a quicktime video
• localisation is useful even if your app is UK-specific
  • e.g. Iraqi boy with a 1:1 iPod touch switched it to Farsi and used Google Image Search to show pictures of what he wanted to the teacher
• support projectors & AirPlay
  • don’t offer resolutions for external display — just pick one and do it well
• there is a control to turn off Game Center at a policy level
  • so go ahead and put it in the app but make the rest of the app work without it
• gap in the middle for 7-10 year olds
  • need more apps like toontastic — structure provided, but space for creation
  • older kids can use general content apps
  • younger kids don’t need so much freedom
  • using iThoughts HD for mindmap, then writing in Pages

example apps

• preschool memory match
• the history of jazz
• slice it — but gets too hard too quickly
• DrawRace 2
• Real Racing 2 HD — but uses up huge amounts of battery
• toca tea party — not a game but a digital toy
  • have a virtual tea party around the iPad
  • lots of other other toca “games” available — see http://toca.com
• math bingo
  • gather “bingo bugs” and then use them in a breakout game
  • 15 year-olds were saying “why do we not have math bingo?”
• penultimate
  • write on a project as you walk around

Q&A

• research?
  • study with university of western scotland
  • two lessons back to back: one with iPad, one with paper & pencil
  • same teacher, same children
  • with paper & pencil, boys and some girls had less emotional engagement
  • with iPad emotional engagement of all pupils was brought up to same level as best kids
  • being submitted to BJET, but may not be published yet
• separate educational version of an app?
  • kids want the real thing
  • universal design is best
  • Fraser tries to buy things off the shelf rather than waiting for educational specific versions
• damages?
  • only had one — parent ran it over with Land Cruiser!
  • kids are careful — the iPad has their name on it
• teachers adapting to technology?
  • about half of the teachers had iPhones/iPod Touches before the programme started
  • the iPad is significantly more approachable than other computers
• how do you find apps?
  • school subscribes to Tap! magazine…
  • more popular than the TES :-)

iOSDev UK: Adapting Content for Apps

Dave Addey & Alyson Fielding, Agant Ltd, @daveaddey & @alysonf

• Why an app?
  • Can you do something with it in dead time?
  • It’s always there when you need it
  • Would you use it yourself?
• Preparing content
  • content definition lets you split up content into small pieces
• iPhone vs iPad
  • use cases are different
  • e.g. full page illustrations just don’t work on an iPhone — universal app just doesn’t show them
• network content:
  • assume no network and make as many things possible as you can
  • then download & cache what you need when network becomes available
  • same goes for submitting stuff — add it to a queue and submit it when a network becomes available
  • e.g. QI app submit a fact
  • provide the app bundle with some initial content to get started
  • if you have information always show it — but show how old it is

content formats

• HTML
• Property list
• Custom XML
• NSAttributedString
• Core Data store
• SQLite database
• bundled media files
• text files — e.g. QI facts to rate
• PDF
• e.g. QI app
  • books came as ePub (HTML)
  • needed tidying, but was very useful
  • errors could be spotted & fixed directly
  • however, not the right format to put in the app
  • used script to transfer into NSAttributedString
  • better presentation
  • better layout for images & text
  • better pagination
  • content definition really helped
• e.g. Malcolm Tucker
  • email views driven from plist
  • Aly edited directly in XCode and rebuild to check
  • email content in HTML
  • attachments in PDF
• e.g. Arsenal app
  • already had a CMS for the website
  • beginning of project — defined an API
  • tweaked the API throughout development, but had something to work from right at the beginning

Helping content experts

• work hand in hand with them from the beginning
• make sure they have a real device that they’re using every day
• try to let the content expert able to make their own build of the app as they change the content
  • anyone working on the content has XCode installed and knows how to build it
  • they also have access to check stuff back in
• let them play with your toys — it’s fun!
• put the content in with the development

stats

• 2.7 million stations are picked from UK Trains picker every month (~88k per day)

Q&A

• testing
  • looking to do more
  • UI testing is a bit of a faff, but is possible

iOSDev UK: Real-World Data (or There and Back Again)

Hamish Allan, Olive Toast

The story of writing Files Pro — an app to take files with you on an iOS device.

• Used Deusty’s CocoaHTTPServer
  • but starting now, would use Matt Gallagher’s simple HTTP server code
• Dropbox has a nice API
  • operations are aynchronous
• Gamekit makes device to device connection over bluetooth easy
• Could use HTML5 to make a PC-based interface to an iOS app
  • Visit a web page served from the device from your PC and see a flexible app within your browser
• iCloud
  • NSFilePresenter tells you when a file transfer has completed
  • iCloud syncs the meta-data about files first, using NSMetadataQuery
• “Your market is not power users”
• Apple is moving towards a flat list of files with search, rather than a hierarchical system

Q&A

• No hooks in iOS for AirDrop (yet?)
• Nor any GameKit APIs which talk to desktop

Apple iPhone Tech Talk London 2009: Networking: From Sockets to GameKit

Paul Danbold danbold@apple.com — Evangelist

This was another really fast presentation with loads of detail. I look forward to grabbing the presentation from the iPhone dev site.

• don’t want to use CFSocket or BSD Socket
  • don’t let you bring up wireless, or involve security
• service discovery:
  • NSNetServices, CFNetServices, dns-sd, BSD Sockets
  • dns-sd is Bonjour or Zeroconf

URL Loading system

• NSURLRequest, NSURLConnection & about 10 other classes (also mutable ones)
• there’s sample code for validating URLs
• recommend to use asynchronous API style:
  • use delegate mechanism — calls connection:didReceiveResponse:
• also connection:didReceiveAuthenticationChallenge:
• finally connectionDidFinishLoading:
• default behaviours should work fine

Local area networking — service discovery

• kick off NSNetServiceBrowser in asynchronous mode, w/delegation
• browser searchForServicesOfType:inDomain:
  • e.g. type _http._tcp in domain local. — don’t go beyond any routers
  • can look for your own types too such as _foo._tcp
• then get myServiceBrowser:didFindService:moreComing:
• call NSNetworkService getInputStream:outputStream to resolve
  • this takes time (many seconds)
  • wait for the user to choose before resolving
  • and let the user decide when to cancel
  • resolveWithTimeout:0.0
• must release input & output stream objects returned by NSNetService
  • bug in Apple’s code — doesn’t obey normal Cocoa behaviour

OutputStream & InputStream

• NSStreamEventHasSpaceAvailable is probably the interesting one
• though you want to handle the errors too…

advertising & publishing

• advertise service with NSNetService initWithDomain:type:name:port
  • domain can be empty — means local
  • name can be blank too — will use device’s iTunes name
• then call publish on service

stop when you’re done

• browsing is fairly lightweight on the network, but you should stop anyway
• the same goes for publishing, when you’ve got all your connected clients

register types & ports

• to register a service type:
  • http://www.dns-sd.org/ServiceTypes.html
  • send them an email, no money changes hands
  • and http://www.iana.org/assignments/port-numbers for one further

game kit — peer to peer

• 3.1 adds WiFi support as well as Bluetooth
• GKSession initWithSessionID:displayName:sessionMode
  • session ID is your Bonjour service type — how you advertise yourself
  • again, can leave displayName as nil for iTunes name
  • sessionMode can be peer to peer (1 to 1) or client/server (multiple clients)
• can’t physically go over 10-20 clients with Bluetooth
  • 3.1 and later is a lot better, but still no more than 3-4 clients
  • Bluetooth also has low bandwidth
• set up delegate and set available to YES
• check other peers with peersWithConnectionState:
  • can be available, already connected, in the process of getting connected
• connectToPeer:withTimeout:
  • generally set timeout to zero to let user cancel if they want
• actual connection made with session:didReceiveConnectionRequestFromPeer: and acceptConnectionFromPeer:error:
• must monitor the network using session:peer:didChangeState:
  • other players can drop out, so you’d have to tear down your session
• send data with sendDataToAllPeers:withDataMode:error: and sendDataToPeers:...
  • can choose unreliable (UDP) or reliable (TCP) data modes
  • as always TCP imposes a performance cost so use sparingly
• receive data with setDataReceiveHandler:withContext: and receiveData:fromPeer:inSession:context:
• always check for errors — buffers fill up on low bandwidth networks
  • check it by using a slow network
• when you’re finished, tear down with disconnectFromAllPeers:
• there’s a GKPeerPickerController for setting up Bluetooth peers
  • doesn’t work for client/server or WiFi
• the only way to find out if Bluetooth is turned on is to use the GKPeerPickerController (it uses private APIs…)
• all data sent & received is NSData-wrapped — design your packaging for network efficiency first and coding efficiency second

Voice chat

• GKVoiceChatClient and ~Service
• sets up socket interface
• handles microphone, echo suppression, etc

network challenges

scoped routing and reachability

• iphone 3.0 and later provides scoped routing
  • keeps both cellular and wifi up at the same time — so cellular connections keep going when you enter a wifi hotspot
  • but this puts a toll on the battery, so you should behave and check for networking changes
• use SystemConfiguration APIs to monitor network state
  • Am I on the network and what kind of network is it?
  • cannot tell you that packets will arrive…
  • if network changes, finish what you’re doing, close connection and start a new one
• use SCNetworkReachabilityRef and check for flags
  • but again use callback APIs since the calls take about 30 seconds
• no point using this to pre-flight as things may change
  • just use to monitor
• can set UIRequiresPersistentWiFi key
  • keeps WiFi live while your app is live
  • shows up UI elements automatically (like offering to turn off Airplane mode)
  • but if the device sleeps, you still lose your WiFi connection

battery use

• listening is cheap, transmitting is expensive
• 3GS sending leaves the antenna in high powered state for 5 seconds
  • so don’t send every 5 seconds — it will leave it in high power continuously
• compress data, send large chunks
• tear down connections when reachability changes

other tips

• try to use the cache as much as possible
• try to resume downloads rather than restart
• use pipelining if poss.
  • ask for lots of things at once and be careful about return order
  • some web proxies and apache configs just break pipelining
• also use multiple connections
• but different network conditions and different servers require different tuning
• test in areas where you know the network is flaky!
• use a packet analyzer — see QA1176
• try to isolate the user from network problems
  • often there’s a transient glitch — try again before alerting the user
• see also Technote TN2152
• look for developer forum postings by eskimo1 :-)

there’s some new sample code available:

• SimpleNetworkStreams
• SimpleURLConnection
• SimpleFTPSample
• Reachability — there’s a new version! The old version had bad code :-)
• BonjourWeb
• WiTap — peer to peer, but doesn’t use GameKit
• GKTank
• GKRocket — work in progress, with voice chat too