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
   

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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
   

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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?
   

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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!
   

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5. Agenda
   1. How to evaluate a library?
   2. Android Libraries you should know about
   3. Demo time
   4. References
   5
   

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6. Agenda
   1. How to evaluate a library?
   2. Android Libraries you should know about
   3. Demo time
   4. References
   6
   

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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]
   

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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?
   

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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
   

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10. What do you know about the
    types of license?
    10
    Reference [1]
    Wait a moment, please!
    

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11. 11
    http://choosealicense.com
    Demystified with <3 by GitHub, Inc.
    

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12. 12
    The Free-Libre / Open Source
    Software (FLOSS) License Slide
    Reference [5]
    

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13. 13
    http://protocoder.org
    

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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]
    

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16. • a company?
    • a community?
    • a single developer?
    16
    Maintenance
    Reference [1]
    Who is the author of this library?
    

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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?
    

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18. 18
    Example:
    https://github.com/square/picasso
    

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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]
    

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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?
    

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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?
    

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22. 22
    Example:
    https://github.com/square/picasso
    

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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]
    

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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!
    

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25. 25
    Example:
    https://github.com/ReactiveX/RxJava
    

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26. 26
    Example:
    https://github.com/ReactiveX/RxJava
    

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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]
    

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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?
    

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30. 30
    Integration
    jCenter or Maven Central?
    

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31. 31
    Example:
    

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32. Agenda
    1. How to evaluate a library?
    2. Android Libraries you should know about
    3. Demo time
    4. References
    32
    

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33. 33
    Butter Knife
    Author Jake Wharton
    License Apache 2.0
    View "injection" library for Android
    https://github.com/JakeWharton/butterknife
    

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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]
    

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35. Binding Views To Activities
    35
    

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36. 36
    Before
    Reference [6]
    

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37. 37
    After
    Reference [6]
    

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38. 38
    The issue
    Reference [6]
    

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39. 39
    The ButterKnife way
    Reference [6]
    

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40. Binding Listeners
    40
    

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41. 41
    Before
    Reference [6]
    

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42. 42
    After
    Reference [6]
    

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43. 43
    Using clicked view
    Reference [6]
    

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44. 44
    Reference [6]
    Other listeners callbacks
    • @OnLongClick
    • @OnItemClick
    • @OnItemLongClick
    • @OnCheckedChanged
    • @OnFocusChange
    • @OnPageChange
    • @OnTextChange
    • @OnTouch
    

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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
    

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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]
    

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47. 47
    EventBus in 4 steps
    1. Define an event.
    2. Register subscribers.
    3. Post event.
    4. Receive event.
    Reference [6]
    

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48. 48
    1. Define an event
    Reference [6]
    • Event: the object that will be delivered.
    • POJO: Plain Old Java Object
    

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49. 49
    2. Register subscribers
    Reference [6]
    Any object can receive events.
    

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50. 50
    3. Post events
    Reference [6]
    

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51. 51
    4. Receive events
    Reference [6]
    • Must have onEvent method or else crash.
    • Params must be something posted.
    

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52. 52
    Picasso
    Author Square
    License Apache 2.0
    A powerful image downloading and caching library for Android.
    https://github.com/square/picasso
    

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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]
    

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54. 54
    With Picasso
    Reference [3]
    Picasso
    .with(context)
    .load(url)
    .into(imageView);
    

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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.
    

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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.
    

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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/
    

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58. 58
    LeakCanary
    Author Square
    License Apache 2.0
    A memory leak detection library for Android and Java.
    https://github.com/square/leakcanary
    

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59. 59
    Other useful libraries…
    • RxAndroid
    • RxJava
    • Retrolambda
    • GSON
    • Timber
    • ion
    • okHttp
    • Dagger
    • SQLBrite
    • Sugar ORM
    • Realm
    • …
    

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60. Agenda
    1. How to evaluate a library?
    2. Android Libraries you should know about
    3. Demo time
    4. References
    60
    

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61. Agenda
    1. How to evaluate a library?
    2. Android Libraries you should know about
    3. Demo time
    4. References
    61
    

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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
    

    

    62
    

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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
    

    

    63
    

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64. Open Source
    Android Libraries
    XII Jornadas SLCENT de Actualización
    Informática y Electrónica
    

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