Becoming an Android Librarian

Becoming an Android Librarian.

Transcript

1. G E T S T R E A M . I O
   Becoming an
   Android Librarian
   

   View Slide

2. G E T S T R E A M . I O
   skydoves
   @github_skydoves
   Android Developer Advocate @ Stream
   Jaewoong Eum
   

   View Slide

3. G E T S T R E A M . I O
   Open-Source Libraries
   

   View Slide

4. G E T S T R E A M . I O
   Open-Source Libraries
   

   View Slide

5. G E T S T R E A M . I O
   Open-Source Libraries
   

   View Slide

6. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   

   View Slide

7. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   

   View Slide

8. G E T S T R E A M . I O
   Library & SDK Lifecycles Design process
   1. Define the problem
   2. Research overall solutions
   3. Verify the feasibility of the solutions
   4. Define dependency relationships
   5. Draw blueprints of the final usage in real-world projects
   6. Design the interfaces
   

   View Slide

9. G E T S T R E A M . I O
   Library & SDK Lifecycles
   Design
   Develop
   Prepare
   Release
   

   View Slide

10. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    

    View Slide

11. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

12. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

13. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

14. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    

    View Slide

15. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

16. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

17. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    Client
    Client
    Client
    Client
    

    View Slide

18. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    private internal
    importance
    protected public
    

    View Slide

19. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    private internal
    importance
    protected public Client
    Client
    Client
    

    View Slide

20. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    class ApiResponseCallAdapter constructor(
    val resultType: Type
    ) : CallAdapter>> {
    override fun responseType(): Type {
    return resultType
    }
    override fun adapt(call: Call): Call> {
    return ApiResponseCallDelegate(call)
    }
    }
    

    View Slide

21. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal class ApiResponseCallAdapter constructor(
    private val resultType: Type
    ) : CallAdapter>> {
    override fun responseType(): Type {
    return resultType
    }
    override fun adapt(call: Call): Call> {
    return ApiResponseCallDelegate(call)
    }
    }
    

    View Slide

22. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    val px = context.dp2Px(dp = 22)
    val sp = context.px2Sp(px = 22)
    

    View Slide

23. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    val px = context.dp2Px(dp = 22) // Unresolved reference
    val sp = context.px2Sp(px = 22) // Unresolved reference
    

    View Slide

24. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    int px = ContextExtensionKt.dp2Px(context, 11);
    int sp = ContextExtensionKt.px2Sp(context, 11);
    

    View Slide

25. G E T S T R E A M . I O
    Development Strategies Minimize API surfaces
    @JvmSynthetic
    internal fun Context.dp2Px(dp: Int): Int {
    val scale = resources.displayMetrics.density
    return (dp * scale).toInt()
    }
    @JvmSynthetic
    internal fun Context.px2Sp(px: Int): Int {
    val scale = resources.displayMetrics.scaledDensity
    return (px / scale).toInt()
    }
    int px = ContextExtensionKt.dp2Px(context, 11); // Unresolved reference
    int sp = ContextExtensionKt.px2Sp(context, 11); // Unresolved reference
    

    View Slide

26. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

    View Slide

27. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

    View Slide

28. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

    View Slide

29. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

    View Slide

30. G E T S T R E A M . I O
    Development Strategies Explicit API mode
    

    View Slide

31. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    

    View Slide

32. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    build.gradle
    module.gradle
    On terminal
    

    View Slide

33. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    module.api
    

    View Slide

34. G E T S T R E A M . I O
    Development Strategies Binary Compatibility Validator
    

    View Slide

35. G E T S T R E A M . I O
    Development Strategies Metalava
    

    View Slide

36. G E T S T R E A M . I O
    Development Strategies Exposing resources
    /classes.jar
    /res/
    /R.txt
    /public.txt
    /assets/
    /libs/name.jar
    /jni/abi_name/name.so
    /proguard.txt
    /lint.jar
    /api.jar
    AAR file
    

    View Slide

37. G E T S T R E A M . I O
    Development Strategies Exposing resources
    /classes.jar
    /res/
    /R.txt
    /public.txt
    /assets/
    /libs/name.jar
    /jni/abi_name/name.so
    /proguard.txt
    /lint.jar
    /api.jar
    AAR file
    res/drawable
    res/layout
    res/menu
    res/values
    res/xml
    res/raw
    res/anim
    res/animator
    res/mipmap
    res/font
    string.xml
    colors.xml
    styles.xml
    dimens.xml
    arrays.xml
    …
    /res/
    /res/values/
    

    View Slide

38. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    #FFFFFF
    #000000
    #57A8D8
    #FBC02D
    
    Library (colors.xml) Project
    val whiteColor = ContextCompat.getColor(this, R.color.white)
    binding.myView.setBackgroundColor(whiteColor)
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="skydoves"
    android:textColor="@color/yellow" />
    

    View Slide

39. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    #FFFFFF
    #000000
    #57A8D8
    #FBC02D
    
    Library (colors.xml)
    val whiteColor = ContextCompat.getColor(this, R.color.white)
    binding.myView.setBackgroundColor(whiteColor)
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="skydoves"
    android:textColor="@color/yellow" />
    Project compile error!
    

    View Slide

40. G E T S T R E A M . I O
    Development Strategies Exposing resources
    public.xml
    

    View Slide

41. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    
    

    View Slide

42. G E T S T R E A M . I O
    Development Strategies Exposing resources
    
    
    

    View Slide

43. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Project (XML) Project (code)
    

    View Slide

44. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Project (XML) Project (code)
    

    View Slide

45. G E T S T R E A M . I O
    Development Strategies Exposing resources
    

    View Slide

46. G E T S T R E A M . I O
    Development Strategies Exposing resources
    

    View Slide

47. G E T S T R E A M . I O
    Development Strategies Exposing resources
    

    View Slide

48. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Library (layout_balloon.xml) Library (Balloon.Builder.kt)
    

    View Slide

49. G E T S T R E A M . I O
    Development Strategies Exposing resources
    ● Some issues have been reported in Crashlytics.
    ● But the reports were not helpful at all.
    ● Occasionally the library behaves very weirdly.
    ● Also it’s really difficult to reproduce.
    

    View Slide

50. G E T S T R E A M . I O
    Development Strategies Exposing resources
    Perhaps..?
    

    View Slide

51. G E T S T R E A M . I O
    Development Strategies Exposing resources
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_vertical"
    android:textColor="@android:color/white" />
    …
    Library (layout_balloon.xml) Project (layout_balloon.xml)
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="skydoves"
    android:textSize="16sp"
    android:textStyle="bold" />
    ...
    

    View Slide

52. G E T S T R E A M . I O
    Development Strategies Exposing resources
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center_vertical"
    android:textColor="@android:color/white" />
    …
    Library (layout_balloon.xml)
    // wrong behaviors
    Project (layout_balloon.xml) // runtime error!
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipChildren="false"
    android:clipToPadding="false"
    android:padding="10dp">
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="skydoves"
    android:textSize="16sp"
    android:textStyle="bold" />
    ...
    

    View Slide

53. G E T S T R E A M . I O
    Development Strategies Resource prefix
    resourcePrefix
    

    View Slide

54. G E T S T R E A M . I O
    Development Strategies Resource prefix
    build.gradle
    

    View Slide

55. G E T S T R E A M . I O
    Development Strategies Resource prefix
    layout_balloon.xml attrs.xml
    

    View Slide

56. G E T S T R E A M . I O
    Development Strategies Resource prefix
    

    View Slide

57. G E T S T R E A M . I O
    Development Strategies
    R class
    Non transitive R class
    

    View Slide

58. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

    View Slide

59. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

    View Slide

60. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    

    View Slide

61. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    com.google.android.material.R
    (:material)
    

    View Slide

62. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    

    View Slide

63. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    

    View Slide

64. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    Transitive dependency
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    

    View Slide

65. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    com.my.library.R
    (:material)
    (:library)
    

    View Slide

66. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

    View Slide

67. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library :material (MDC)
    implementation implementation
    com.my.library.R
    (:material)
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:material)
    (:library)
    (:app)
    Wow, a million of LoC in R classes in a minute!
    

    View Slide

68. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    Dex format has 64K limit for methods and fields references!
    64K (65,536 = 64 x 1024 (2^10))
    

    View Slide

69. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    

    View Slide

70. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    android.nonTransitiveRClass=true
    gradle.properties
    

    View Slide

71. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app :library
    :material
    (MDC)
    implementation implementation
    com.my.library.R
    (:library)
    com.google.android.material.R
    (:material)
    com.my.app.R
    (:app)
    Refer to its own resources without pulling resources from
    dependencies.
    

    View Slide

72. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    Before After
    

    View Slide

73. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    aar size diff
    226054 bytes -> 214538 bytes (11516 bytes reduced)
    10,000 projects
    2260540000 bytes -> 2145380000 bytes (≈115 MB reduced)
    100,000 projects
    22605400000 bytes -> 21453800000 bytes (≈1.1 GB reduced)
    1,000,000 projects
    226054000000 bytes -> 214538000000 bytes (≈10 GB reduced)
    100,000,000 end-users
    22605400000000 bytes -> 21453800000000 bytes (≈1 TB reduced)
    

    View Slide

74. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app
    :feature1
    :feature2
    :feature3
    com.my.app.R
    (:feature1)
    (:feature2)
    (:feature3)
    (:app)
    Unresolved reference
    

    View Slide

75. G E T S T R E A M . I O
    Development Strategies Non transitive R class
    :app
    :feature1
    :feature2
    :feature3
    com.my.app.R
    (:feature1)
    (:feature2)
    (:feature3)
    (:app)
    full name package
    import with namespacing
    

    View Slide

76. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    

    View Slide

77. G E T S T R E A M . I O
    Preparation Documentation (KDoc)
    

    View Slide

78. G E T S T R E A M . I O
    Preparation Documentation (Dokka)
    ./gradlew dokkaHtml
    ./gradlew dokkaHtmlMultiModule
    ./gradlew dokkaJavadoc
    

    View Slide

79. G E T S T R E A M . I O
    Preparation Documentation (README)
    

    View Slide

80. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    

    View Slide

81. G E T S T R E A M . I O
    Release Maven
    

    View Slide

82. G E T S T R E A M . I O
    Release Maven repositories
    mavenCentral()
    google()
    jcenter()
    

    View Slide

83. G E T S T R E A M . I O
    Release Maven central repository
    mavenCentral()
    

    View Slide

84. G E T S T R E A M . I O
    Release Maven central repository
    1. Registering a Sonatype account
    2. Generating a GPG key pair
    3. Setting up publication in your project
    a. Maven publishing setup with Gradle
    b. Signing artifacts with GPG key
    c. Configure pom files
    d. Per-module Gradle setup
    4. Publish to sonatype repository
    5. Evaluate and close the ticket on staging
    repositories
    

    View Slide

85. G E T S T R E A M . I O
    Release Maven central repository
    🔗 https://bit.ly/386yJt1 🔗 https://bit.ly/3KU3Xk4
    

    View Slide

86. G E T S T R E A M . I O
    Release Jitpack
    maven { url 'https://jitpack.io' }
    

    View Slide

87. G E T S T R E A M . I O
    Library & SDK Lifecycles
    Design
    Develop
    Prepare
    Release
    Management
    

    View Slide

88. G E T S T R E A M . I O
    Management Code formatting
    

    View Slide

89. G E T S T R E A M . I O
    Management Code formatting
    

    View Slide

90. G E T S T R E A M . I O
    Verifying and Marketing Community
    

    View Slide

91. G E T S T R E A M . I O
    Verifying and Marketing Technical contents
    

    View Slide

92. G E T S T R E A M . I O
    Verifying and Marketing Example projects
    Codes speak louder than words!
    

    View Slide

93. G E T S T R E A M . I O
    https://github.com/skydoves
    jaewoong.eum@getstream.io
    https://twitter.com/github_skydoves
    https://medium.com/@skydoves
    Contact
    

    View Slide

94. G E T S T R E A M . I O
    Thank you.
    

    View Slide