Building Wunderlist. Lessons Learned.

In this talk I cover the lessons we learned during the creation of Wunderlist 2, things that many people don't know until they face the specific problem, useful things that we sometimes forget, useful tips, advices, experiences, etc.

1. Building Wunderlist. Lessons learned. Cesar Valiente
2. 6Wunderkinder and Wunderlist 2
3. Me :-) Cesar Valiente https://twitter.com/CesarValiente https://plus.google.com/u/0/+CesarValiente/ https://github.com/CesarValiente 3
4. 1. Databases
5. 1.1 Opening modes • getReadableDatabase vs getWritableDatabase. • Just getWritableDatabase mode will call onCreate, onOpen, onUpgrade, etc. • Both methods may takes long time —> avoid main thread. 5
6. 1.2 Transactions • onUpgrade executes its own transaction. • Be careful with the exceptions, if something happens, your changes won’t be committed!! 6
7. 1.2.1 Transactions 7
8. 1.2.2 Transactions 8
9. 1.3 Simple queries • Use simpleQueryFor”Xxx” instead making a rawQuery to get simple stuff. 9
10. 2. Android internals
11. 2.1 AsyncTasks and multithreading • Different ways to work on different Android versions: • < 1.6 executed serially. • 1.6 < 3.0 uses a pool of threads allowing tasks in parallel. • Since 3.0, again, back to execution on a single thread. 11
12. • Try to update the UI as soon as possible. • Use AsyncTasks just for short time operations. • For longer operations use java.util.concurrent package such as Executor, ThreadPoolExecutor and FutureTask. • Concurrency management —> JavaRX, Spotify Trickle, etc. 2.1.1 AsyncTasks and multithreading 12
13. 2.2 Broadcast receivers • BroadcastReceiver just valid for the duration of the call onReceive. • Use LocalBroadcastManager (support Lib v4), or setPackage (ics onwards). 13
14. 2.2.1 Broadcast receivers 14
15. 2.2.2 Broadcast receivers 15
16. 2.3 Services • Services run in the main thread of its hosting process. • When the service has finished it should stop itself. • Multiple components can bind to the service at once, but when all of them unbind, the service is destroyed. 16
17. • IntentServices are handled on a single worker thread. 2.4 IntentServices 17
18. 2.5 Notifications • Different notifications styles. • Respect versions styles. • Be careful updating the notification, it can give you problems, delays, etc. 18
19. 2.6 Keyboard issues • Try to use “send” as “a way to accept the text”. • Try to offer, always you can, a way to accept the text using the UI. • Avoid to use EditText in ListViews. 19
20. 2.7 Widgets • Different widget versions. • Try to offer the “same experience” as much as you can. • Several widget instances is something useful. • Use widget ids and save some data in a persistent storage. 20
21. 3. Android and… Java! 21
22. 3.1 Caches • Try to cache your data as much as you can. • Use Lists and Maps. • Avoid “infinite sizes”, follow some strategy. • Keep it updated. 22
23. 3.2 For loops • Two different “for loop types”, conventional (old school) and enhanced. • Think carefully which one are you going to use. Performance differences. 23
24. 4. UI and Ux
25. • You can create a lot of different stuff by code/xml, so if you can,… do it!! :-) • Some examples: 25 4.1 Graphics, assets,…
26. 4.2 Make your own views! • SlidingLayerLib on Github: released under Apache License v2. • Forked and starred hundred of times. • Improved since we released it by the community. 26
27. 5. Android mix
28. 5.1 DashClock Widget extension • Useful to show info. • If you don’t have anything to show, then don’t show it, save space for other notifications. • Thanks to Jake Wharton for the comment/tip :-). 28
29. 5.2 Rating dialog • Fact: people usually just rate to give you a bad one. • Much more good ratings with a rating dialog than without it. • Don’t force the user to vote. 29
30. 5.3 Open Source • Try to keep up to date about the “Android Open Source world”. • Don’t reinvent the wheel. • Collaborate if you want/can. 30
31. • Be careful with licenses —> Really important! —> Law problems! • Privative Licenses. • Open Source Licenses: • Reciprocal licenses (strong copyleft): • GNU GPL, Eclipse Public License, Affero License, etc. • Partially closable licenses (weak copyleft): • LGPL, Mozilla License, etc. • Permissive licenses: • BSD, MIT, Apache License v2, etc. • Public domain. 5.3.1 Open Source 31
32. 5.4 Managing several apps • Several apps to manage, Google Play, Google For Education, Amazon App store, Samsung, etc. • Gradle is your friend! ;-) • Use flavors. 32
33. 5.4.1 Managing several apps 33
34. 5.5 Testing and Continuous Integration • UI testing: Robotium, UIAutomator, Espresso, Calabash, etc. • Others: JUnit, Robolectric, etc. • Really important/useful —> C.I. software like Jenkins, Hudson, Travis, etc. 34
35. 5.6 Tools we use 35
36. Questions?
37. Thank you!! :-)
38. License • Content: (cc) 2014 Cesar Valiente Gordo. Some rights reserved. This document is distributed under the Creative Commons Attribution-ShareAlike 3.0 license, available in http:// creativecommons.org/licenses/by-sa/3.0/ • All images used in this presentation belong to their owners.