[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/

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