Developing for Android

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