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[AppdevCon '19] Demystifying Android Libraries

[AppdevCon '19] Demystifying Android Libraries

Building an Android library in the current times is way different than what it used to be earlier. Things have changed considerably and keeping up to date with them is now a necessity rather than just some acquirable knowledge.

In this session, you will dive deeper into best practices and ways of architecting Android libraries. You will get to learn about the common pitfalls and how to overcome them by using the right approach such as leveraging architecture components and making your Android libraries lifecycle-aware. You will also understand how one can leverage Kotlin language when developing Android libraries as well as information around API design and exploring the path to becoming a better Android Library Developer.

By the end of this session, you will be all set to build Android libraries that scale and have API which contributes to the developer's happiness.

Event Link: https://web.archive.org/web/20190315154423/https://appdevcon.nl/session/demystifying-android-libraries/

Ab4fa54bccd8073d0c0b4d4a2dd4193f?s=128

Nishant Srivastava

March 15, 2019
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  1. 1

  2. OSS Android libraries developed 2

  3. How does Gradle process Android Libraries @nisrulz 3

  4. How does Gradle process Android Libraries repositories { jCenter() }

    dependencies { implementation 'com.github.nisrulz:awesomelib:1.0' ... } 4 @nisrulz
  5. How does Gradle process Android Libraries repositories { jCenter() }

    dependencies { implementation 'com.github.nisrulz:awesomelib:1.0' ... } 5 @nisrulz // Dependency Notation
  6. How does Gradle process Android Libraries repositories { jCenter() }

    dependencies { implementation 'com/github/nisrulz/awesomelib/1.0' ... } 6 @nisrulz
  7. How does Gradle process Android Libraries implementation 'com.github.nisrulz:awesomelib:1.0' 7 @nisrulz

  8. How does Gradle process Android Libraries implementation 'com/github/nisrulz/awesomelib/1.0' 8 @nisrulz

  9. How does Gradle process Android Libraries implementation 'com/github/nisrulz/awesomelib/1.0' 9 @nisrulz

  10. How does Gradle process Android Libraries implementation 'com/github/nisrulz/awesomelib/1.0' 10 @nisrulz

  11. How does Gradle process Android Libraries implementation 'com.github.nisrulz:awesomelib:1.0' 11 @nisrulz

  12. Android ARchive(AAR) @nisrulz 12

  13. 13 @nisrulz

  14. 14 @nisrulz

  15. AAR = Java ARchive(JAR) + Resources 15 @nisrulz

  16. AAR = Java ARchive(JAR) + Resources Sensey: https://github.com/nisrulz/sensey 16 @nisrulz

  17. AAR = Java ARchive(JAR) + Resources @nisrulz 17

  18. Sensey’s build.gradle dependencies { ... // Other testing dependencies //

    Transitive dependency: Support Compat library implementation "com.android.support:support-compat:27.0.2" } 18 @nisrulz
  19. Using AAR as dependency @nisrulz 19

  20. Using an AAR as dependency repositories{ flatDir{ dirs 'libs' }

    } dependencies { implementation(name:'nameOfYourAARFileWithoutExtension', ext:'aar') } @nisrulz 20
  21. Using an AAR as dependency repositories{ flatDir{ dirs 'libs' }

    } dependencies { implementation(name:'nameOfYourAARFileWithoutExtension', ext:'aar') } // No transitive dependencies of the library are downloaded 21 @nisrulz
  22. Why doesn’t my AAR download transitive dependencies? @nisrulz 22

  23. Sensey’s AAR 23 @nisrulz

  24. Sensey’s AAR No build.gradle file 24 @nisrulz

  25. Maven Artifact 25 @nisrulz

  26. Maven Artifact 26 @nisrulz

  27. POM? 27 @nisrulz

  28. POM • Project Object Model • XML file • Configuration

    details used by Maven to build the project 28 @nisrulz
  29. POM POM of Sensey Android Library <?xml version="1.0" encoding="UTF-8"?> <project

    xsi:schemaLocation="..." xmlns="..."xmlns:xsi="..."> <modelVersion>4.0.0</modelVersion> <groupId>com.github.nisrulz</groupId><artifactId>sensey</artifactId><version>1.8.0</version> <packaging>aar</packaging><name>sensey</name> <description>Android library which makes playing with sensor events &amp; detecting gestures a breeze.</description> <url>https://github.com/nisrulz/sensey</url> <licenses> <license> <name>The Apache Software License, Version 2.0</name><url>http://www.apache.org/licenses/LICENSE-2.0.txt</url> </license> </licenses> <developers> <developer><id>nisrulz</id><name>Nishant Srivastava</name><email>nisrulz@gmail.com</email></developer> </developers> <scm> <connection>https://github.com/nisrulz/sensey.git</connection> <developerConnection>https://github.com/nisrulz/sensey.git</developerConnection> <url>https://github.com/nisrulz/sensey</url> </scm> <dependencies> <dependency> <groupId>com.android.support</groupId> <artifactId>support-compat</artifactId><version>27.0.2</version> <scope>runtime</scope> </dependency> <dependency> ... </dependency> </dependencies> </project> 29 @nisrulz
  30. POM POM of Sensey Android Library <?xml version="1.0" encoding="UTF-8"?> <project

    xsi:schemaLocation="..." xmlns="..."xmlns:xsi="..."> <modelVersion>4.0.0</modelVersion> <groupId>com.github.nisrulz</groupId><artifactId>sensey</artifactId><version>1.8.0</version> <packaging>aar</packaging><name>sensey</name> <description>Android library which makes playing with sensor events &amp; detecting gestures a breeze.</description> <url>https://github.com/nisrulz/sensey</url> <licenses> <license> <name>The Apache Software License, Version 2.0</name><url>http://www.apache.org/licenses/LICENSE-2.0.txt</url> </license> </licenses> <developers> <developer><id>nisrulz</id><name>Nishant Srivastava</name><email>nisrulz@gmail.com</email></developer> </developers> <scm> <connection>https://github.com/nisrulz/sensey.git</connection> <developerConnection>https://github.com/nisrulz/sensey.git</developerConnection> <url>https://github.com/nisrulz/sensey</url> </scm> <dependencies> <dependency> <groupId>com.android.support</groupId> <artifactId>support-compat</artifactId><version>27.0.2</version> <scope>runtime</scope> </dependency> <dependency> ... </dependency> </dependencies> </project> 30 @nisrulz
  31. POM POM of Sensey Android Library <?xml version="1.0" encoding="UTF-8"?> <project

    xsi:schemaLocation="..." xmlns="..."xmlns:xsi="..."> ... <dependencies> <dependency> <groupId>com.android.support</groupId> <artifactId>support-compat</artifactId><version>27.0.2</version> <scope>runtime</scope> </dependency> <dependency> ... </dependency> </dependencies> </project> 31 @nisrulz
  32. Bundled Proguard Configs 32 @nisrulz

  33. Bundled Proguard Configs android { release { minifyEnabled true //

    Rules to be used during the AAR generation proguardFiles 'proguard-rules-for-building-library.pro' } ... } 33 @nisrulz
  34. Bundled Proguard Configs android { release { minifyEnabled true //

    Rules to be used during the AAR generation proguardFiles 'proguard-rules-for-building-library.pro' // Rules appended to the integrating app consumerProguardFiles 'proguard-rules-for-using-library.pro' } ... } 34 @nisrulz
  35. Bundled Proguard Configs 35 @nisrulz

  36. Bundled Proguard Configs 36 @nisrulz

  37. Bundled Proguard Configs # Fuel’s bundled Proguard file # Without

    specifically keeping this class, # callbacks on android don't function properly. -keep class com.github.kittinunf.fuel.android.util.AndroidEnvironment 37 @nisrulz
  38. Bundled Proguard Configs # DON'T DO THIS # Do not

    obfuscate the input class files -dontobfuscate # Optimizes variable allocation on the local variable frame. -optimizations !code/allocation/variable # Preserved as entry points -keep public class * { public protected *; } 38 @nisrulz
  39. Bundled Proguard Configs # DON'T DO THIS # Adding the

    below in library proguard rules disables # the optimizations in the Android app -dontoptimize 39 @nisrulz
  40. Bundled Proguard Configs # To check the merged configuration #

    Add the below to your app’s current proguard rules -printconfiguration proguard-merged-config.txt 40 @nisrulz
  41. Bundled Proguard Configs 41 @nisrulz

  42. Modularization 42 @nisrulz

  43. Modularization 43 @nisrulz

  44. Modularization EasyDeviceInfo: https://github.com/nisrulz/easydeviceinfo 44 @nisrulz

  45. Modularization dependencies { def libVer = {latest_version} // Base +

    Ads Bundled Library implementation "com.github.nisrulz:easydeviceinfo:$libVer" // Base Library implementation "com.github.nisrulz:easydeviceinfo-base:$libVer" // Ads Library implementation "com.github.nisrulz:easydeviceinfo-ads:$libVer" } 45 @nisrulz
  46. Modularization <!-- POM file for com.github.nisrulz:easydeviceinfo --> <project xsi:schemaLocation="..." xmlns="..."

    xmlns:xsi="..."> ... <dependencies> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-ads</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-base</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> ... </dependencies> </project> 46 @nisrulz
  47. Modularization <!-- POM file for com.github.nisrulz:easydeviceinfo--> <project xsi:schemaLocation="..." xmlns="..." xmlns:xsi="...">

    ... <dependencies> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-ads</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-base</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> ... </dependencies> </project> 47 @nisrulz
  48. Modularization <!-- POM file for com.github.nisrulz:easydeviceinfo--> <project xsi:schemaLocation="..." xmlns="..." xmlns:xsi="...">

    ... <dependencies> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-ads</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-base</artifactId> <version>2.5.0</version> <scope>compile</scope> </dependency> ... </dependencies> </project> 48 @nisrulz
  49. Modularization <!-- POM file for com.github.nisrulz:easydeviceinfo-ads --> <project xsi:schemaLocation="..." xmlns="..."

    xmlns:xsi="..."> ... <dependencies> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-common</artifactId><version>2.5.0</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.google.android.gms</groupId> <artifactId>play-services-ads-identifier</artifactId><version>16.0.0</version> <scope>runtime</scope> </dependency> ... </dependencies> </project> 49 @nisrulz
  50. Modularization <!-- POM file for com.github.nisrulz:easydeviceinfo-ads --> <project xsi:schemaLocation="..." xmlns="..."

    xmlns:xsi="..."> ... <dependencies> <dependency> <groupId>com.github.nisrulz</groupId> <artifactId>easydeviceinfo-common</artifactId><version>2.5.0</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.google.android.gms</groupId> <artifactId>play-services-ads-identifier</artifactId><version>16.0.0</version> <scope>runtime</scope> </dependency> ... </dependencies> </project> 50 @nisrulz
  51. Avoiding Resource Name Conflicts 51 @nisrulz

  52. Conflict occurs between a library & app resource > Project

    will not compile What happens when... 52 @nisrulz
  53. Conflict occurs between 2 libraries integrated in the app >

    Resources from library defined first in build.gradle gets included What happens when... 53 @nisrulz
  54. Solution? 54 @nisrulz

  55. Add a prefix to all your resources. Solution? 55 @nisrulz

  56. Add a prefix to all your resources. How? Solution? 56

    @nisrulz
  57. Add a prefix to all your resources. How? • Enforce

    this in Android Studio Solution? 57 @nisrulz
  58. Add a prefix to all your resources. How? • Enforce

    this in Android Studio • Declare in build.gradle of library android { resourcePrefix 'YOUR_PREFIX_' // i.e 'sensey_' } Solution? 58 @nisrulz
  59. Solution? Resource named ‘app_name’ does not start with the project’s

    resource prefix ‘sensey_’; Rename to `sensey_app_name`? 59 @nisrulz
  60. minSdkVersion Restriction 60 @nisrulz

  61. minSdkVersion of app >= minSdkVersion of library minSdk Restriction 61

    @nisrulz
  62. minSdk Restriction 62 @nisrulz

  63. Manifest merger failed : uses-sdk:minSdkVersion 14 cannot be smaller than

    version 21 declared in library [:sensey] Suggestion: + Use a compatible library with a minSdk of at most 14 + Increase this project's minSdk version to at least 21 + Use tools:overrideLibrary="com.github.nisrulz.sensey" to force usage (may lead to runtime failures) minSdk Restriction 63 @nisrulz
  64. Manifest merger failed : uses-sdk:minSdkVersion 14 cannot be smaller than

    version 21 declared in library [:sensey] Suggestion: + Use a compatible library with a minSdk of at most 14 + Increase this project's minSdk version to at least 21 + Use tools:overrideLibrary="com.github.nisrulz.sensey" to force usage (may lead to runtime failures) minSdk Restriction 64 @nisrulz
  65. Manifest merger failed : uses-sdk:minSdkVersion 14 cannot be smaller than

    version 21 declared in library [:sensey] Suggestion: + Use a compatible library with a minSdk of at most 14 + Increase this project's minSdk version to at least 21 + Use tools:overrideLibrary="com.github.nisrulz.sensey" to force usage (may lead to runtime failures) minSdk Restriction 65 @nisrulz
  66. <manifest xmlns:android="..." xmlns:tools="http://schemas.android.com/tools" package="com.github.nisrulz.senseysample"> <uses-sdk tools:overrideLibrary="com.github.nisrulz.sensey"/> <application ...> ... </application>

    </manifest> minSdk Restriction 66 @nisrulz
  67. <manifest xmlns:android="..." xmlns:tools="http://schemas.android.com/tools" package="com.github.nisrulz.senseysample"> <uses-sdk tools:overrideLibrary="com.github.nisrulz.sensey"/> <application ...> ... </application>

    </manifest> minSdk Restriction 67 @nisrulz
  68. Access Visibility vs Code Organization 68 @nisrulz

  69. Visibility vs Organization 69 @nisrulz

  70. Visibility vs Organization • Code organized in individual packages; everything

    is public 70 @nisrulz
  71. Visibility vs Organization • Code organized inside one package; Classes

    and methods are package private and only public on demand 71 @nisrulz
  72. Visibility vs Organization • Code organized inside the module i.e

    individual packages Classes and methods are internal and only public on demand (in Kotlin land) 72 @nisrulz
  73. Visibility vs Organization • internal and only public on demand

    (in Kotlin land) 73 @nisrulz
  74. Visibility vs Organization • Code organized inside the module i.e

    individual packages Classes and methods are internal and only public on demand (in Kotlin land) • Drawback ◦ Need dependency on kotlin std library 74 @nisrulz
  75. Lifecycle-Aware Android Library 75 @nisrulz

  76. Lifecycle Components Classes designed to help deal with Android lifecycle

    • Lifecycle • LifecycleOwner • LifecycleObserver 76 @nisrulz
  77. Lifecycle Owner 77 @nisrulz

  78. Lifecycle Owner + Lifecycle 78 @nisrulz

  79. Lifecycle Owner + Lifecycle • • • • 79 @nisrulz

  80. Lifecycle Owner + Lifecycle class MainActivity extends AppCompatActivity() {...} 80

    @nisrulz
  81. Lifecycle Owner + Lifecycle class MainActivity extends AppCompatActivity() {...} public

    class AppCompatActivity extends FragmentActivity{...} 81 @nisrulz
  82. Lifecycle Owner + Lifecycle class MainActivity extends AppCompatActivity() {...} public

    class AppCompatActivity extends FragmentActivity{...} public class FragmentActivity extends SupportActivity {...} 82 @nisrulz
  83. Lifecycle Owner + Lifecycle class MainActivity extends AppCompatActivity() {...} public

    class AppCompatActivity extends FragmentActivity{...} public class FragmentActivity extends SupportActivity {...} public class SupportActivity extends Activity implements LifecycleOwner, Component { ... public Lifecycle getLifecycle() {return this.mLifecycleRegistry();} ... } 83 @nisrulz
  84. Lifecycle Owner + Lifecycle class MainActivity extends AppCompatActivity() {...} public

    class AppCompatActivity extends FragmentActivity{...} public class FragmentActivity extends SupportActivity {...} public class SupportActivity extends Activity implements LifecycleOwner, Component { ... public Lifecycle getLifecycle() {return this.mLifecycleRegistry();} ... } 84 @nisrulz
  85. Lifecycle Observer 85 @nisrulz

  86. Lifecycle Observer 86 @nisrulz

  87. LifecycleObserver dependencies { def lifecycleVer = "2.0.0" // Runtime implementation

    "androidx.lifecycle:lifecycle-runtime:$lifecycleVer" // Annotation Support annotationProcessor "androidx.lifecycle:lifecycle-compiler:$lifecycleVer" ... } 87 @nisrulz
  88. LifecycleObserver public class AwesomeLib implements LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_CREATE) public void

    init() { ... } @OnLifecycleEvent(Lifecycle.Event.ON_START) public void libOnStart() { ... } ... @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY) public void cleanup() { ... } } 88 @nisrulz
  89. LifecycleOwner class MainActivity : AppCompatActivity() { val awesomeLib = AwesomeLib()

    override fun onStart() { ... // Add lifecycle observer lifecycle.addObserver(awesomeLib) } override fun onStop() { ... // Remove lifecycle observer lifecycle.removeObserver(awesomeLib) } } 89 @nisrulz
  90. LifecycleAware Library 90 @nisrulz

  91. ProcessLifecycleOwner Class that tracks the lifecycle of whole application process

    91 @nisrulz
  92. ProcessLifecycleOwner dependencies { // For ProcessLifecycleOwner implementation "androidx.lifecycle:lifecycle-extensions:2.0.0" ... }

    92 @nisrulz
  93. ProcessLifecycleOwner Does something weird… 93 @nisrulz

  94. ProcessLifecycleOwner Does something weird… Adding lifecycle-extensions artifact > automatically adds

    <provider> element to the merged manifest 94 @nisrulz
  95. ProcessLifecycleOwner 95 @nisrulz

  96. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-process" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 96 @nisrulz
  97. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-process" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 97 @nisrulz
  98. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="android.arch.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-trojan" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 98 @nisrulz Pre-AndroidX
  99. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="android.arch.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-trojan" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 99 @nisrulz Pre-AndroidX
  100. ProcessLifecycleOwner 100 @nisrulz Pre-AndroidX

  101. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-process" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 101 @nisrulz AndroidX
  102. ProcessLifecycleOwner <manifest > <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="com.example.app.lifecycle-process" android:exported="false" android:multiprocess="true"

    /> </application> </manifest> 102 @nisrulz AndroidX
  103. ProcessLifecycleOwner // Internal class to initialize Lifecycles. public class ProcessLifecycleOwnerInitializer

    extends ContentProvider { @Override public boolean onCreate() { ... ProcessLifecycleOwner.init(getContext()); return true; } ... } 103 @nisrulz
  104. ProcessLifecycleOwner Why? To invoke ProcessLifecycleOwner as soon as process starts

    104 @nisrulz
  105. ProcessLifecycleOwner Why? To invoke ProcessLifecycleOwner as soon as process starts

    Drawback? Initializes ProcessLifecycleOwner even if your app does not use it! 105 @nisrulz
  106. ProcessLifecycleOwner How to get rid of it in app? 106

    @nisrulz
  107. ProcessLifecycleOwner How to get rid of it in app? Use

    Merge rule marker in app’s AndroidManifest.xml: // Remove marked element from the merged manifest tools:node="remove" 107 @nisrulz
  108. ProcessLifecycleOwner <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="${applicationId}.lifecycle-process" xmlns:tools="http://schemas.android.com/tools" tools:node="remove" /> </application>

    108 @nisrulz App’s AndroidManifest.xml
  109. ProcessLifecycleOwner <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="${applicationId}.lifecycle-process" xmlns:tools="http://schemas.android.com/tools" tools:node="remove" /> </application>

    109 @nisrulz App’s AndroidManifest.xml
  110. ProcessLifecycleOwner <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="${applicationId}.lifecycle-process" xmlns:tools="http://schemas.android.com/tools" tools:node="remove" /> </application>

    110 @nisrulz App’s AndroidManifest.xml
  111. ProcessLifecycleOwner <application> ... <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="${applicationId}.lifecycle-process" xmlns:tools="http://schemas.android.com/tools" tools:node="remove" /> </application>

    111 @nisrulz App’s AndroidManifest.xml
  112. Auto Initialize Android Library 112 @nisrulz

  113. AutoInit Android Library Android Libraries need Android context to handle

    simple tasks such as • Hook into Android Runtime • Access app resources • Use System Services • Register BroadcastReceiver 113 @nisrulz
  114. AutoInit Android Library public class MyApplication extends Application { @Override

    public void onCreate() { super.onCreate(); // Init android library AwesomeLib.getInstance().init(this); } } 114 @nisrulz
  115. AutoInit Android Library public class MyApplication extends Application { @Override

    public void onCreate() { super.onCreate(); // Init android library AwesomeLib.getInstance().init(this); } } 115 @nisrulz
  116. AutoInit Android Library public class MyApplication extends Application { @Override

    public void onCreate() { super.onCreate(); // Init android library AwesomeLib.getInstance().init(this); } } 116 @nisrulz
  117. AutoInit Android Library <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:name=".MyApplication" ... > 117

    @nisrulz
  118. AutoInit Android Library <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:name=".MyApplication" ... > 118

    @nisrulz
  119. AutoInit Android Library ContentProvider can be used to simplify the

    process. 119 @nisrulz
  120. AutoInit Android Library ContentProvider can be used to simplify the

    process. Simply because ContentProvider • Is created and initialized (on the main thread) before all other components • Participate in manifest merging at build time. 120 @nisrulz
  121. AutoInit Android Library public class AwesomeLibInitProvider extends ContentProvider { ...

    @Override public boolean onCreate() { // get the context (Application context) Context context = getContext(); // initialize AwesomeLib here AwesomeLib.getInstance().init(context); return false; } ... } 121 @nisrulz
  122. AutoInit Android Library public class AwesomeLibInitProvider extends ContentProvider { ...

    @Override public boolean onCreate() { // get the context (Application context) Context context = getContext(); // initialize AwesomeLib here AwesomeLib.getInstance().init(context); return false; } ... } 122 @nisrulz
  123. AutoInit Android Library <manifest xmlns:android=".." package="github.nisrulz.sample.awesomelib"> <application> <provider android:name=".AwesomeLibInitProvider" android:authorities="${applicationId}.awesomelibinitprovider"

    android:enabled="true" android:exported="false"/> </application> </manifest> 123 @nisrulz
  124. AutoInit Android Library <manifest xmlns:android=".." package="github.nisrulz.sample.awesomelib"> <application> <provider android:name=".AwesomeLibInitProvider" android:authorities="${applicationId}.awesomelibinitprovider"

    android:enabled="true" android:exported="false"/> </application> </manifest> 124 @nisrulz
  125. AutoInit Android Library <manifest xmlns:android=".." package="github.nisrulz.sample.awesomelib"> <application> <provider android:name=".AwesomeLibInitProvider" android:authorities="${applicationId}.awesomelibinitprovider"

    android:enabled="true" android:exported="false"/> </application> </manifest> 125 @nisrulz
  126. AutoInit Android Library <manifest xmlns:android=".." package="github.nisrulz.sample.awesomelib"> <application> <provider android:name=".AwesomeLibInitProvider" android:authorities="${applicationId}.awesomelibinitprovider"

    android:enabled="true" android:exported="false"/> </application> </manifest> 126 @nisrulz
  127. AutoInit Android Library ContentProvider can be used to simplify the

    process. 127 @nisrulz
  128. AutoInit Android Library ContentProvider can be used to simplify the

    process. Challenges: • There can be only one Content Provider with a given “authority” string • Only run on main thread 128 @nisrulz
  129. AutoInit Android Library ContentProvider can be used to simplify the

    process. 129 @nisrulz
  130. AutoInit Android Library ContentProvider can be used to simplify the

    process. Why this is a bad idea: • Increases startup time • Bloats applications even when not used • Abusing functionality of ContentProvider 130 @nisrulz
  131. AutoInit Android Library ContentProvider can be used to simplify the

    process. Why this is a bad idea: • Increases startup time (Solution: async initialize) • Bloats applications even when not used • Abusing functionality of ContentProvider 131 @nisrulz
  132. AutoInit Android Library Some android libraries that use this... 132

    @nisrulz
  133. AutoInit Android Library ProcessLifecycleOwner [androidx.lifecycle:lifecycle-extensions:2.0.0] <application> <provider android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer" android:authorities="${applicationId}.lifecycle-process" android:exported="false"

    android:multiprocess="true" /> </application> 133 @nisrulz
  134. AutoInit Android Library Firebase [com.google.firebase:firebase-common:16.0.5] <application> <provider android:name="com.google.firebase.provider.FirebaseInitProvider" android:authorities="${applicationId}.firebaseinitprovider" android:exported="false"

    android:initOrder="100" /> </application> 134 @nisrulz
  135. AutoInit Android Library Facebook-Core [com.facebook.android:facebook-core:4.34.0] <application> <provider android:name="com.facebook.internal.FacebookInitProvider" android:authorities="${applicationId}.FacebookInitProvider" android:exported="false"

    /> </application> 135 @nisrulz
  136. AutoInit Android Library Facebook-Marketing [com.facebook.android:facebook-marketing:4.34.0] <application> <provider android:name="com.facebook.marketing.internal.MarketingInitProvider" android:authorities="${applicationId}.MarketingInitProvider" android:exported="false"

    /> </application> 136 @nisrulz
  137. AutoInit Android Library Crashlytics [com.crashlytics.sdk.android:crashlytics:2.9.5] <application> <provider android:name="com.crashlytics.android.CrashlyticsInitProvider" android:authorities="${applicationId}.crashlyticsinitprovider" android:exported="false"

    android:initOrder="90" /> </application> 137 @nisrulz
  138. AutoInit Android Library Picasso // Pre - v2.71828 Picasso.with(this).load("...<url>...").into(imageView); //

    After - v2.71828 Picasso.get().load("...<url>...").into(imageView); 138 @nisrulz
  139. AutoInit Android Library Picasso // Pre - v2.71828 Picasso.with(this).load("...<url>...").into(imageView); //

    After - v2.71828 Picasso.get().load("...<url>...").into(imageView); 139 @nisrulz
  140. AutoInit Android Library Picasso [com.squareup.picasso:picasso:2.71828] <application> <provider android:name=".PicassoContentProvider" android:authorities="${applicationId}.com.squareup.picasso3" android:exported="false"/>

    </application> 140 @nisrulz
  141. Links/References Android Libraries I have built: https://github.com/nisrulz/nisrulz.github.io#open-source-co ntributions Auto initialize

    android library example: https://github.com/nisrulz/android-examples/tree/develop/Au toInitLibrary Lifecycle Aware android library example: https://github.com/nisrulz/android-examples/tree/develop/Li feCycleCompForLib 141 @nisrulz
  142. 142 twitter.com/nisrulz github.com/nisrulz www.nisrulz.com

  143. twitter.com/nisrulz github.com/nisrulz www.nisrulz.com 143