[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/

Transcript

1. View Slide

2. OSS Android libraries developed
   2
   

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3. How does Gradle process
   Android Libraries
   @nisrulz 3
   

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

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

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

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7. How does Gradle process
   Android Libraries
   implementation 'com.github.nisrulz:awesomelib:1.0'
   7
   @nisrulz
   

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

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

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

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

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12. Android ARchive(AAR)
    @nisrulz 12
    

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13. 13
    @nisrulz
    

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14. 14
    @nisrulz
    

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

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

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

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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
    

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19. Using AAR as dependency
    @nisrulz 19
    

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

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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
    

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22. Why doesn’t my AAR
    download transitive
    dependencies?
    @nisrulz 22
    

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23. Sensey’s AAR
    23
    @nisrulz
    

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

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25. Maven Artifact
    25
    @nisrulz
    

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26. Maven Artifact
    26
    @nisrulz
    

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27. POM?
    27
    @nisrulz
    

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28. POM
    ● Project Object Model
    ● XML file
    ● Configuration details used by Maven to build the project
    28
    @nisrulz
    

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29. POM
    POM of Sensey Android Library
    
    
    4.0.0
    com.github.nisrulzsensey1.8.0
    aarsensey
    Android library which makes playing with sensor events & detecting gestures a breeze.
    https://github.com/nisrulz/sensey
    
    
    The Apache Software License, Version 2.0http://www.apache.org/licenses/LICENSE-2.0.txt
    
    
    
    nisrulzNishant Srivastavanisrulz@gmail.com
    
    
    https://github.com/nisrulz/sensey.git
    https://github.com/nisrulz/sensey.git
    https://github.com/nisrulz/sensey
    
    
    
    com.android.support
    support-compat27.0.2
    runtime
    
    
    ...
    
    
    
    29
    @nisrulz
    

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30. POM
    POM of Sensey Android Library
    
    
    4.0.0
    com.github.nisrulzsensey1.8.0
    aarsensey
    Android library which makes playing with sensor events & detecting gestures a breeze.
    https://github.com/nisrulz/sensey
    
    
    The Apache Software License, Version 2.0http://www.apache.org/licenses/LICENSE-2.0.txt
    
    
    
    nisrulzNishant Srivastavanisrulz@gmail.com
    
    
    https://github.com/nisrulz/sensey.git
    https://github.com/nisrulz/sensey.git
    https://github.com/nisrulz/sensey
    
    
    
    com.android.support
    support-compat27.0.2
    runtime
    
    
    ...
    
    
    
    30
    @nisrulz
    

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31. POM
    POM of Sensey Android Library
    
    
    ...
    
    
    com.android.support
    support-compat27.0.2
    runtime
    
    
    ...
    
    
    
    31
    @nisrulz
    

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32. Bundled Proguard Configs
    32
    @nisrulz
    

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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
    

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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
    

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35. Bundled Proguard Configs
    35
    @nisrulz
    

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36. Bundled Proguard Configs
    36
    @nisrulz
    

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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
    

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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
    

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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
    

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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
    

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41. Bundled Proguard Configs
    41
    @nisrulz
    

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42. Modularization
    42
    @nisrulz
    

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43. Modularization
    43
    @nisrulz
    

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

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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
    

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46. Modularization
    
    
    ...
    
    
    com.github.nisrulz
    easydeviceinfo-ads 2.5.0
    compile
    
    
    com.github.nisrulz
    easydeviceinfo-base 2.5.0
    compile
    
    ...
    
    
    46
    @nisrulz
    

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47. Modularization
    
    
    ...
    
    
    com.github.nisrulz
    easydeviceinfo-ads 2.5.0
    compile
    
    
    com.github.nisrulz
    easydeviceinfo-base 2.5.0
    compile
    
    ...
    
    
    47
    @nisrulz
    

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48. Modularization
    
    
    ...
    
    
    com.github.nisrulz
    easydeviceinfo-ads 2.5.0
    compile
    
    
    com.github.nisrulz
    easydeviceinfo-base 2.5.0
    compile
    
    ...
    
    
    48
    @nisrulz
    

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49. Modularization
    
    
    ...
    
    
    com.github.nisrulz
    easydeviceinfo-common2.5.0
    compile
    
    
    com.google.android.gms
    play-services-ads-identifier16.0.0
    runtime
    
    ...
    
    
    49
    @nisrulz
    

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50. Modularization
    
    
    ...
    
    
    com.github.nisrulz
    easydeviceinfo-common2.5.0
    compile
    
    
    com.google.android.gms
    play-services-ads-identifier16.0.0
    runtime
    
    ...
    
    
    50
    @nisrulz
    

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51. Avoiding Resource Name
    Conflicts
    51
    @nisrulz
    

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52. Conflict occurs between a library & app resource
    > Project will not compile
    What happens when...
    52
    @nisrulz
    

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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
    

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54. Solution?
    54
    @nisrulz
    

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

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

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

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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
    

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59. Solution?
    Resource named ‘app_name’ does not start with the project’s
    resource prefix ‘sensey_’;
    Rename to `sensey_app_name`?
    59
    @nisrulz
    

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60. minSdkVersion Restriction
    60
    @nisrulz
    

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

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62. minSdk Restriction
    62
    @nisrulz
    

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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
    

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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
    

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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
    

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66. xmlns:tools="http://schemas.android.com/tools"
    package="com.github.nisrulz.senseysample">
    
    
    ...
    
    
    minSdk Restriction
    66
    @nisrulz
    

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67. xmlns:tools="http://schemas.android.com/tools"
    package="com.github.nisrulz.senseysample">
    
    
    ...
    
    
    minSdk Restriction
    67
    @nisrulz
    

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68. Access Visibility
    vs
    Code Organization
    68
    @nisrulz
    

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69. Visibility vs Organization
    69
    @nisrulz
    

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70. Visibility vs Organization
    ● Code organized in individual packages; everything is
    public
    70
    @nisrulz
    

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71. Visibility vs Organization
    ● Code organized inside one package; Classes and methods
    are package private and only public on demand
    71
    @nisrulz
    

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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
    

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73. Visibility vs Organization
    ● internal and only public on demand (in Kotlin land)
    73
    @nisrulz
    

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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
    

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75. Lifecycle-Aware
    Android Library
    75
    @nisrulz
    

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76. Lifecycle Components
    Classes designed to help deal with Android
    lifecycle
    ● Lifecycle
    ● LifecycleOwner
    ● LifecycleObserver
    76
    @nisrulz
    

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77. Lifecycle Owner
    77
    @nisrulz
    

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78. Lifecycle Owner + Lifecycle
    78
    @nisrulz
    

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79. Lifecycle Owner + Lifecycle
    ●
    ●
    ●
    ●
    79
    @nisrulz
    

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

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

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

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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
    

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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
    

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85. Lifecycle Observer
    85
    @nisrulz
    

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86. Lifecycle Observer
    86
    @nisrulz
    

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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
    

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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
    

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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
    

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90. LifecycleAware Library
    90
    @nisrulz
    

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

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

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93. ProcessLifecycleOwner
    Does something weird…
    93
    @nisrulz
    

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94. ProcessLifecycleOwner
    Does something weird…
    Adding lifecycle-extensions artifact
    > automatically adds element to the merged
    manifest
    94
    @nisrulz
    

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95. ProcessLifecycleOwner
    95
    @nisrulz
    

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

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

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

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

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100. ProcessLifecycleOwner
     100
     @nisrulz
     Pre-AndroidX
     

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

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

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103. ProcessLifecycleOwner
     // Internal class to initialize Lifecycles.
     public class ProcessLifecycleOwnerInitializer extends ContentProvider {
     @Override
     public boolean onCreate() {
     ...
     ProcessLifecycleOwner.init(getContext());
     return true;
     }
     ...
     }
     103
     @nisrulz
     

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

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105. ProcessLifecycleOwner
     Why?
     To invoke ProcessLifecycleOwner as soon as process
     starts
     Drawback?
     Initializes ProcessLifecycleOwner even if your app
     does not use it!
     105
     @nisrulz
     

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106. ProcessLifecycleOwner
     How to get rid of it in app?
     106
     @nisrulz
     

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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
     

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

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

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

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

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112. Auto Initialize
     Android Library
     112
     @nisrulz
     

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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
     

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

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115. AutoInit Android Library
     public class MyApplication extends Application {
     @Override
     public void onCreate() {
     super.onCreate();
     // Init android library
     AwesomeLib.getInstance().init(this);
     }
     }
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116. AutoInit Android Library
     public class MyApplication extends Application {
     @Override
     public void onCreate() {
     super.onCreate();
     // Init android library
     AwesomeLib.getInstance().init(this);
     }
     }
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117. AutoInit Android Library
     android:icon="@mipmap/ic_launcher"
     android:label="@string/app_name"
     android:name=".MyApplication"
     ... >
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118. AutoInit Android Library
     android:icon="@mipmap/ic_launcher"
     android:label="@string/app_name"
     android:name=".MyApplication"
     ... >
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119. AutoInit Android Library
     ContentProvider can be used to simplify the process.
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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.
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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;
     }
     ...
     }
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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;
     }
     ...
     }
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123. AutoInit Android Library
     package="github.nisrulz.sample.awesomelib">
     
     android:name=".AwesomeLibInitProvider"
     android:authorities="${applicationId}.awesomelibinitprovider"
     android:enabled="true"
     android:exported="false"/>
     
     
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124. AutoInit Android Library
     package="github.nisrulz.sample.awesomelib">
     
     android:name=".AwesomeLibInitProvider"
     android:authorities="${applicationId}.awesomelibinitprovider"
     android:enabled="true"
     android:exported="false"/>
     
     
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125. AutoInit Android Library
     package="github.nisrulz.sample.awesomelib">
     
     android:name=".AwesomeLibInitProvider"
     android:authorities="${applicationId}.awesomelibinitprovider"
     android:enabled="true"
     android:exported="false"/>
     
     
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126. AutoInit Android Library
     package="github.nisrulz.sample.awesomelib">
     
     android:name=".AwesomeLibInitProvider"
     android:authorities="${applicationId}.awesomelibinitprovider"
     android:enabled="true"
     android:exported="false"/>
     
     
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127. AutoInit Android Library
     ContentProvider can be used to simplify the process.
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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
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129. AutoInit Android Library
     ContentProvider can be used to simplify the process.
     129
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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
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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
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132. AutoInit Android Library
     Some android libraries that use this...
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133. AutoInit Android Library
     ProcessLifecycleOwner
     [androidx.lifecycle:lifecycle-extensions:2.0.0]
     
     android:name="androidx.lifecycle.ProcessLifecycleOwnerInitializer"
     android:authorities="${applicationId}.lifecycle-process"
     android:exported="false"
     android:multiprocess="true" />
     
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134. AutoInit Android Library
     Firebase
     [com.google.firebase:firebase-common:16.0.5]
     
     android:name="com.google.firebase.provider.FirebaseInitProvider"
     android:authorities="${applicationId}.firebaseinitprovider"
     android:exported="false"
     android:initOrder="100" />
     
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135. AutoInit Android Library
     Facebook-Core
     [com.facebook.android:facebook-core:4.34.0]
     
     android:name="com.facebook.internal.FacebookInitProvider"
     android:authorities="${applicationId}.FacebookInitProvider"
     android:exported="false" />
     
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136. AutoInit Android Library
     Facebook-Marketing
     [com.facebook.android:facebook-marketing:4.34.0]
     
     android:name="com.facebook.marketing.internal.MarketingInitProvider"
     android:authorities="${applicationId}.MarketingInitProvider"
     android:exported="false" />
     
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137. AutoInit Android Library
     Crashlytics
     [com.crashlytics.sdk.android:crashlytics:2.9.5]
     
     android:name="com.crashlytics.android.CrashlyticsInitProvider"
     android:authorities="${applicationId}.crashlyticsinitprovider"
     android:exported="false"
     android:initOrder="90" />
     
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138. AutoInit Android Library
     Picasso
     // Pre - v2.71828
     Picasso.with(this).load("......").into(imageView);
     // After - v2.71828
     Picasso.get().load("......").into(imageView);
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139. AutoInit Android Library
     Picasso
     // Pre - v2.71828
     Picasso.with(this).load("......").into(imageView);
     // After - v2.71828
     Picasso.get().load("......").into(imageView);
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140. AutoInit Android Library
     Picasso
     [com.squareup.picasso:picasso:2.71828]
     
     android:name=".PicassoContentProvider"
     android:authorities="${applicationId}.com.squareup.picasso3"
     android:exported="false"/>
     
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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
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142. 142
     twitter.com/nisrulz
     github.com/nisrulz
     www.nisrulz.com
     

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