Developing for Android

Presented by Chet Haase and Romain Guy at Bay Area Android Developer Group on November 30, 2015

Transcript

1. Romain Guy Chet Haase Developing for Android +RomainGuy, @romainguy +ChetHaase, @chethaase Development for Developers by Developers Managers
2. Developing for Android medium.com @chethaase
3. Why is Mobile Development So Difficult?
4. • Limited • Shared Memory
5. • Slower than desktop & server • Throttled CPU Much
6. • [See previous slide] • Texture uploads are expensive • Fill rate vs. density GPU
7. • Larger application heaps lead to • More task thrashing • Slower allocations • Slower collections • More garbage collector activity Memory == Performance
8. Allocate Enumerate Mark Collect
9. Allocate Enumerate Mark Collect Pause Pause Dalvik
10. Allocate Enumerate Mark Collect Pause ART
11. Slot Available Slot Freed
12. Slot Available Oh Noze! Slot Freed Pause GC_FOR_ALLOC
13. ART
14. • Your device is faster than your users’ • And has more memory • Moore’s Law does not always apply Low-End Devices
15. • You have 16ms per frame • To do everything • Consistency is good Smooth Frame Rate
16. • Dalvik vs. ART • Language != runtime != hardware Runtime
17. Language != Platform Java programming language Runtime Hardware
18. Server-Land Moving, compacting collector CPU: Memory: very very fast Basically ∞ Java programming language Server runtime Server
19. Android No compaction Idle compaction CPU: wayyyy slower Memory: 512MB - 2GB Java programming language ART Mobile Dalvik
20. • Android is single-threaded UI system • (mostly) • Eliminate unnecessary work on UI thread UI Thread
21. • Storage performance varies • Storage size varies • So apk size matters Storage
22. • Your network is faster than your users’ • And maybe cheaper, too Network
23. • Every Device is a Village • Tragedy of the Commons And Finally
24. Language & libraries
25. • Don’t use serialization • Use Android data structures • Be mindful of XML and JSON usage • Avoid JNI • Primitives vs boxed primitives • Avoid reflection • Be careful with finalizers Know Your Language
26. Networking
27. • Don’t over-sync • Allow delayed downloading • Google Cloud Messaging • GCM Network Manager (Job Scheduler) • Don’t poll • Only sync what you need to Syncing
28. • Don’t assume anything about the network • Develop for low-end networks • And test for them, too Network quality
29. • Design back-end APIs for mobile usage patterns • Minimize and compress data Data & protocols
30. Storage
31. • Don’t hard-code file paths • Persist relative paths only • Use storage cache for temp files • Avoid SQLite for simple needs • Avoid using too many databases • Let user choose content storage location Random stuff about storage
32. Romain Guy Chet Haase Developing for Android +RomainGuy, @romainguy +ChetHaase, @chethaase Development for Developers by Developers Q & A