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Becoming an Android Librarian (Android World Wi...

Jaewoong
February 01, 2023

Becoming an Android Librarian (Android World Wide 2023 Jan)

Becoming an Android Librarian (Android World Wide 2023 Jan)

Jaewoong

February 01, 2023
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  1. G E T S T R E A M .

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

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

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

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

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

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

    I O Library & SDK Lifecycles Design process 1. Define a problem 2. Research overall ideas 3. Verify the feasibility of your ideas 4. Investigate dependencies 5. Draw blueprints of application interfaces 6. Design the application interfaces
  8. G E T S T R E A M .

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

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

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

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

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

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

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

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

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

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

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

    I O Development Strategies Minimize API surfaces class ApiResponseCallAdapter constructor( val resultType: Type ) : CallAdapter<Type, Call<ApiResponse<Type>>> { override fun responseType(): Type { return resultType } override fun adapt(call: Call<Type>): Call<ApiResponse<Type>> { return ApiResponseCallDelegate(call) } } Client
  20. 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<Type, Call<ApiResponse<Type>>> { override fun responseType(): Type { return resultType } override fun adapt(call: Call<Type>): Call<ApiResponse<Type>> { return ApiResponseCallDelegate(call) } } Client
  21. 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)
  22. 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
  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() } int px = ContextExtensionKt.dp2Px(context, 11); int sp = ContextExtensionKt.px2Sp(context, 11);
  24. 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
  25. G E T S T R E A M .

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

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

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

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

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

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

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

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

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

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

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

    I O Development Strategies Exposing resources <resources> <color name="white">#FFFFFF</color> <color name="black">#000000</color> <color name="blue">#57A8D8</color> <color name="yellow">#FBC02D</color> </resources> Library (colors.xml) val whiteColor = ContextCompat.getColor(this, R.color.white) binding.myView.setBackgroundColor(whiteColor) <TextView 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!
  39. G E T S T R E A M .

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

    I O Development Strategies Exposing resources <?xml version="1.0" encoding="utf-8"?> <resources xmlns:tools="http://schemas.android.com/tools"> <!-- Definitions of layouts to be exposed as public ⟶ <public name="balloon_layout_body" type="layout" /> <public name="balloon_layout_overlay" type="layout" /> <!-- Definitions of attributes to be exposed as public ⟶ <public name="balloon_drawableStart" type="attr" /> <public name="balloon_drawableEnd" type="attr" /> <public name="balloon_drawableTop" type="attr" /> <public name="balloon_drawableBottom" type="attr" /> <public name="balloon_drawablePadding" type="attr" /> <public name="balloon_drawableTintColor" type="attr" /> <public name="balloon_drawableWidth" type="attr" /> <public name="balloon_drawableHeight" type="attr" /> <public name="balloon_drawableSquareSize" type="attr" /> Library (/res/values/public.xml)
  41. G E T S T R E A M .

    I O Development Strategies Exposing resources <?xml version="1.0" encoding="utf-8"?> <resources xmlns:tools="http://schemas.android.com/tools"> <!-- Definitions of layouts to be exposed as public ⟶ <public name="balloon_layout_body" type="layout" /> <public name="balloon_layout_overlay" type="layout" /> <!-- Definitions of attributes to be exposed as public ⟶ <public name="balloon_drawableStart" type="attr" /> <public name="balloon_drawableEnd" type="attr" /> <public name="balloon_drawableTop" type="attr" /> <public name="balloon_drawableBottom" type="attr" /> <public name="balloon_drawablePadding" type="attr" /> <public name="balloon_drawableTintColor" type="attr" /> <public name="balloon_drawableWidth" type="attr" /> <public name="balloon_drawableHeight" type="attr" /> <public name="balloon_drawableSquareSize" type="attr" /> Library (/res/values/public.xml) res/drawable res/layout res/menu res/values res/xml res/raw res/anim res/animator res/mipmap res/font String.xml attrs.xml colors.xml styles.xml dimens.xml arrays.xml /res/ /res/values/
  42. G E T S T R E A M .

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

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

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

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

    I O Development Strategies Exposing resources Library (layout_balloon.xml) Library (Balloon.Builder.kt)
  47. 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.
  48. G E T S T R E A M .

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

    I O Development Strategies Exposing resources <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="center" android:clipChildren="false" android:clipToPadding="false" android:padding="10dp"> <com.skydoves.balloon.vectortext.VectorTextView 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) <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="center" android:clipChildren="false" android:clipToPadding="false" android:padding="10dp"> <TextView 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" /> ...
  50. G E T S T R E A M .

    I O Development Strategies Exposing resources <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="center" android:clipChildren="false" android:clipToPadding="false" android:padding="10dp"> <com.skydoves.balloon.vectortext.VectorTextView 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! <FrameLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="center" android:clipChildren="false" android:clipToPadding="false" android:padding="10dp"> <TextView 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" /> ...
  51. G E T S T R E A M .

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    I O Development Strategies Non transitive R class
  66. 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!
  67. 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))
  68. G E T S T R E A M .

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

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

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

    I O Development Strategies Non transitive R class Before After (enabled non transitive R class)
  72. 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 end-users 2260540000 bytes -> 2145380000 bytes (≈115 MB reduced) 100,000 end-users 22605400000 bytes -> 21453800000 bytes (≈1.1 GB reduced) 1,000,000 end-users 226054000000 bytes -> 214538000000 bytes (≈10 GB reduced) 100,000,000 end-users 22605400000000 bytes -> 21453800000000 bytes (≈1 TB reduced)
  73. 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
  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) full name package import with namespacing
  75. G E T S T R E A M .

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

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

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

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

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

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

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

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

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

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

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

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

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

    I O Blog Post 🔗 https://bit.ly/3Qim5ZB
  90. G E T S T R E A M .

    I O https://github.com/skydoves [email protected] https://twitter.com/github_skydoves https://medium.com/@skydoves Contact
  91. G E T S T R E A M .

    I O Thank you.