Open Source Android Libraries

Presentación utilizada en XII Jornadas SLCENT de Actualización Informática y Electrónica. 28 de Octubre de 2015, Almería.

http://hacklabalmeria.net/actividades/2015/10/28/xii-jornadas-slcent.html

Esta charla trata de ofrecer una visión general sobre licencias Open Source y librerías Open Source para Android.

Transcript

1. Open Source Android Libraries XII Jornadas SLCENT de Actualización Informática y Electrónica
2. About me José Juan Sánchez Hernández Android Developer (In my spare time :) Member and collaborator of: - Android Almería Developer Group - HackLab Almería @josejuansanchez 2
3. Who are you? 3 • How many Android developers are there in the room? • How many of you have used open source libraries in your projects?
4. This talk is based on the next talks/slides: 1. Can you work without open source libraries?
 Gabriele Mariotti. Droidcon Italy 2015. slides video 2. Android Library Love.
 Andrew Watson. DevFestMN 2015. slides video 3. Don't reinvent the wheel, use libraries.
 Pavel Junak. Droidcon Berlin 2015. slides video 6. A few small useful libraries. Victor Cassone. link
 
 
 4 Advertisement Thanks!
5. Agenda 1. How to evaluate a library? 2. Android Libraries you should know about 3. Demo time 4. References 5
6. Agenda 1. How to evaluate a library? 2. Android Libraries you should know about 3. Demo time 4. References 6
7. • Never choose the first library. • Read the README. • Pay attention to some important points: • License • Maintenance • Support • Documentation • Quality code 7 Before using open source libraries Reference [1]
8. • Check if the license under which the library is released. • Check if the license is compatible with your project. • Pay attention to legal issues. 8 License Reference [1] Can I use it?
9. • Open Source does not mean you are free to do anything you want with the library. • You have to respect the license. 9 What is Open Source? Reference [1] Open Source != Free
10. What do you know about the types of license? 10 Reference [1] Wait a moment, please!
11. 11 http://choosealicense.com Demystified with <3 by GitHub, Inc.
12. 12 The Free-Libre / Open Source Software (FLOSS) License Slide Reference [5]
13. 13 http://protocoder.org
15. • Never choose the first library. • Read the README. • Pay attention to some important points: • License • Maintenance • Support • Documentation • Quality code 15 Before using open source libraries Reference [1]
16. • a company? • a community? • a single developer? 16 Maintenance Reference [1] Who is the author of this library?
17. • Checks the last commits in the repository. • Check how often the project is updated (or was updated). • If you use a library which is no longer maintained, you could have problems in the future. 17 Maintenance Reference [1] Is this library still alive?
18. 18 Example: https://github.com/square/picasso
19. • Never choose the first library. • Read the README. • Pay attention to some important points: • License • Maintenance • Support • Documentation • Quality code 19 Before using open source libraries Reference [1]
20. • Evaluate what kind of support you can find using it. • Popular libraries have a tag (and a lot of posts) on stackoverflow. • Popular libraries have a G+ community or a very good issues section where to find a lot of comments and posts. 20 Support Reference [1] Can someone help me?
21. • Check how many issues are open. • Check how many issues were closed. • If you find 300 issues open and 1 issue closed is not a good evidence. 21 Issues Reference [1] Is someone fixing the issues?
22. 22 Example: https://github.com/square/picasso
23. • Never choose the first library. • Read the README. • Pay attention to some important points: • License • Maintenance • Support • Documentation • Quality code 23 Before using open source libraries Reference [1]
24. Check if the library provides: • Doc / Wiki section. • A good README file. • Examples. • A demo in Google Play. 24 Documentation Reference [1] You can’t use the library without documentation!
25. 25 Example: https://github.com/ReactiveX/RxJava
26. 26 Example: https://github.com/ReactiveX/RxJava
27. • Never choose the first library. • Read the README. • Pay attention to some important points: • License • Maintenance • Support • Documentation • Quality code 27 Before using open source libraries Reference [1]
28. • The existence of Unit Tests is a good indicator of a serious project. • Check how it is written. • Check if the authors use comments, javadoc, 
 Clean Code, SOLID principles. 28 Quality code Reference [1] Is it good?
30. 30 Integration jCenter or Maven Central?
31. 31 Example:
32. Agenda 1. How to evaluate a library? 2. Android Libraries you should know about 3. Demo time 4. References 32
33. 33 Butter Knife Author Jake Wharton License Apache 2.0 View "injection" library for Android https://github.com/JakeWharton/butterknife
34. • Uses annotation for code generation (no reflection). • Reduces boilerplate for view assignment. • Removes anonymous inner classes for listeners associated with views. • Simplifies resource lookups. 34 What does ButterKnife do? Reference [6]
35. Binding Views To Activities 35
36. 36 Before Reference [6]
37. 37 After Reference [6]
38. 38 The issue Reference [6]
39. 39 The ButterKnife way Reference [6]
40. Binding Listeners 40
41. 41 Before Reference [6]
42. 42 After Reference [6]
43. 43 Using clicked view Reference [6]
44. 44 Reference [6] Other listeners callbacks • @OnLongClick • @OnItemClick • @OnItemLongClick • @OnCheckedChanged • @OnFocusChange • @OnPageChange • @OnTextChange • @OnTouch
45. 45 EventBus Author Greenrobot License Apache 2.0 Android optimized event bus that simplifies communication between Activities, Fragments, Threads, Services, etc. https://github.com/greenrobot/EventBus
46. • Developed by greenRobot. • Inspired by Guava’s EventBus. • Android optimized way to simplify communication in application. • Claims to have best performance. • There are other options (Otto, TinyBus, … etc). 46 About EventBus Reference [6]
47. 47 EventBus in 4 steps 1. Define an event. 2. Register subscribers. 3. Post event. 4. Receive event. Reference [6]
48. 48 1. Define an event Reference [6] • Event: the object that will be delivered. • POJO: Plain Old Java Object
49. 49 2. Register subscribers Reference [6] Any object can receive events.
50. 50 3. Post events Reference [6]
51. 51 4. Receive events Reference [6] • Must have onEvent method or else crash. • Params must be something posted.
52. 52 Picasso Author Square License Apache 2.0 A powerful image downloading and caching library for Android. https://github.com/square/picasso
53. • Developed by Square. • Never again: AsyncTask with HttpConnection downloading image. • Picasso allows image loading in your application, often in one line of code! 53 About Picasso Reference [3]
54. 54 With Picasso Reference [3] Picasso .with(context) .load(url) .into(imageView);
55. 55 Place Holders Reference [3] Picasso.with(context) .load(url) .placeholder(R.drawable.placeholder) .error(R.drawable.placeholder_error) .into(imageView); • Supports both download and error placeholders as optional features. • A request will be retried 3 times before the error placeholder is shown.
56. 56 Image Transformations Reference [3] Picasso.with(context) .load(url) .resize(50, 50) .centerCrop() .into(imageView) • Transform images to better fit into layouts and to reduce memory size.
57. 57 Retrofit Author Square License Apache 2.0 A type-safe REST client for Android which intelligently maps an API into a client interface using annotations. http://square.github.io/retrofit/
58. 58 LeakCanary Author Square License Apache 2.0 A memory leak detection library for Android and Java. https://github.com/square/leakcanary
59. 59 Other useful libraries… • RxAndroid • RxJava • Retrolambda • GSON • Timber • ion • okHttp • Dagger • SQLBrite • Sugar ORM • Realm • …
60. Agenda 1. How to evaluate a library? 2. Android Libraries you should know about 3. Demo time 4. References 60
61. Agenda 1. How to evaluate a library? 2. Android Libraries you should know about 3. Demo time 4. References 61
62. References / Talks 1. Can you work without open source libraries?
 Gabriele Mariotti. Droidcon Italy 2015. slides video 2. Android Library Love.
 Andrew Watson. DevFestMN 2015. slides video 3. Don't reinvent the wheel, use libraries.
 Pavel Junak. Droidcon Berlin 2015. slides video 
 
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63. References / Links 4. Choosing an open source license doesn’t need to be scary. GitHub, Inc. link 5. The Free-Libre / Open Source Software (FLOSS) License Slide. David A. Wheeler. 2007. link 6. A few small useful libraries. Victor Cassone. link 
 
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64. Open Source Android Libraries XII Jornadas SLCENT de Actualización Informática y Electrónica