On October 23rd, 2014, we updated our
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Mobiles are not computers• CPU power on par with Intel P4• HD screens coming• But: itit‘‘ss NOT A PCNOT A PC
Short sessionsPalmSource, The Zen of Palm
Bursty usagePalmSource, The Zen of Palm
Features / Satisfaction• Adding new features gets PR boost• On a PC, more features = better app• In mobile, things are different
Satisfaction / Features
Satisfaction / Features - II• Increased power widens sweet spot• Faster CPU– Complex features less of an issue• More memory– App can be larger
What to do?
Best practices• GUI design is not fixed science– Sometimes, bad is good• Like a design pattern– Feel free to adapt
Dont waste screen space• Screen real estate is severely limited– 800x480 is common baseline• HD resolution in mobile is NOT PC-like– Screen is MUCH SMALLER• Users dont have 10:10 eyes
Clicks are evil• Mobile sessions are short– Whiney wife wants to know where she‘ll eat• Clicks require dexterity
Clicks are evil - II• Solution: minimize clicks• Dumb users are more affected– „Simple flow“ – few clicks– „Complex flow“ – more clicks
Clicks are evil - III• What do they doright?
Clicks are evil - IV• Quick access tocommon functions!• Less quick access torarely needed ones!
Clicks are evil - V• Good approach: paper prototypes•• EXERCISEEXERCISE– Cell phone– Paper– Pen– Scissor/Knife/Dagger/fingernail– Comrade
Input is evil• Data input on a PC is no issue– QWERTY keyboard• On mobile, it‘s less funny
Input is evil - II• Hardware keyboards– Somewhat fast– Still tedious• Swype/Graffiti/whatever– Slow– Take up screen real estate (!)
Input is evil - III• Cache common input• „App thinks ahead“– Palm Pre style
In Rome, like the Romans• Consistency is everything– Inconsistent behavior => unhappyness• Humans are animals of habit– Rote learning is effective– E.g. arms disassembly drill
In Rome, like the Romans - II• OS vendors set strong standards• Users are accustomed to them•• BetterBetter blend inblend in
In Rome, like the Romans - III
Swift like the devil• Mobile phones are used in high pressure• Delays are unacceptable and annoying• Make the GUI respond swiftly
Swift like the devil - II• Not always possible– Show progress indicator– Show „spin ball“
Boom-shake-a-lake!• Desktop users have high accuracy input– Mice are accurate as hell– Trackpads are decent, too– Position and Activation are two steps• On mobile, things are different– Hello, touchscreen
Boom-shake-a-lake! - II• Resistive screen– With stylus: 05cm x 0.5cm– Without stylus: see below• Capacitive screen– Very inaccurate (even with stylus)– 1cm x 1cm is reasonable
Boom-shake-a-lake - III• The world is not an ideal place• Users use cell phones on the run– Trains– Cars– Walking== Vibration== Vibration
Boom-shake-a-lake - IV• Misclicks are really evil on touchscreens– No Select/Confirm-Pattern• Misclicks cause unhappy users– They fucked up– but your app gave them the opportunity
Boom-shake-a-lake V• Avoid Misclicks– LARGE controls– Group controls sensibly• Mitigate Misclicks– Ask before wreaking havoc
Boom-shake-a-lake VI• What is bad?
Boom-shake-a-lake VI• Up and Delete• Ouch
Save power• Power usage is critical– Apps which drain power are unpopular• Problems:– Reconnection loops– Network keepalive– Screen colors (OLED)
Colors count• In direct sunlight, screen contrast suffers
Colors count - II• Black causes more reflections than white– But: OLED power issue
Don‘t be annoying• Push messages are useful– Inform users– Can increase retention (see studies)• IF the notification area does not overflow
Test on humans• „Betriebsblindheit“– Blindness of operator• Developer of app understands his GUI– Developer is not user– User does not know your design specs
Test on humans - II
Test on humans - III• Testers „burn“– They get accustomed• The world is full of testers– Check forums or ask on the road– Not being able to find testers: ouch!!!
Further reading• [SPOL]http://www.joelonsoftware.com/uibook/fog0000000249.html• [GUI]http://shop.oreilly.com/product/9780596008031.do• [ZEN]http://www.cs.uml.edu/~fredm/courses/91.308-fall05/palm/zenofpalm.pdf