Reach 4 million Unity developers with your Android library

Recording: http://www.butterflytv.net/player.html?videoId=from_pi21371431281378228

Reach 4 million Unity developers with your Android library With the 45% market share, Unity is the most popular game engine in the world. Featuring reach API exposed in C# and JavaScript, a tremendous amount of assets and libraries available and Asset Store - an open platform to sell or share them. While talk will discuss why it is time to make your Android library or SDK available to Unity developers. How to expose it to C# using Unity API, JNI and a bit of magic. What problems you'll face with while porting. And last but not least, how to publish your work to Unity Asset Store.

Transcript

1. Reach 4 million Unity developers
   with your Android library
   Vitaliy Zasadnyy
   Senior Unity Dev @ GetSocial
   Manager @ GDG Lviv
   Ankara Android Dev Days
   May 11-12 , 2015
   

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2. Why Unity?
   

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3. #AndroidDevDays
   

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4. #AndroidDevDays
   Daily Users
   0 225 450 675 900
   Source: Unreleased McKinsey report; Facebook http://newsroom.fb.com/company-info/
   M M M M
   

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5. #AndroidDevDays
   0 225 450 675 900
   Source: Unreleased McKinsey report; Facebook http://newsroom.fb.com/company-info/
   Daily Users
   M M M M
   

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6. #AndroidDevDays
   Unity Developers
   Unity
   4M
   Source: Unity Technologies
   

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7. #AndroidDevDays
   Unity Developers
   Unity
   4M
   18M
   Worldwide
   Source: Global Developer Population and Demographic Study 2014
   

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8. #AndroidDevDays
   Unity Developers
   Source: Unity Technologies
   

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9. #AndroidDevDays
   Unity is Android
   in game engine world
   

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10. #AndroidDevDays
    

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11. #AndroidDevDays
    GetSocial Unity SDK Architecture
    Android
    SDK
    iOS
    SDK
    iOS Bridge Android Bridge
    C# API
    Unity SDK
    Java Objective C C#
    

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12. #AndroidDevDays
    During Android Build
    Android
    SDK
    iOS
    SDK
    iOS Bridge Android Bridge
    C# API
    Unity SDK
    

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13. #AndroidDevDays
    Unity Game Structure
    Android
    Mono VM
    Unity Core
    Unity
    C# Scripts
    OS
    Apk
    

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14. #AndroidDevDays
    Android
    Mono VM
    Unity Core
    Unity
    C# Scripts
    Java
    Code
    ?
    Unity Game Structure
    OS
    Apk
    

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15. #AndroidDevDays
    Android / Java Unity / C#
    primitive types primitive types
    java.lang.String string
    java.lang.Object AndroidJavaObject
    java.lang.Class AndroidJavaClass
    java.lang.Runnable AndroidJavaRunnable
    java.lang.Proxy AndroidJavaProxy
    Provided Wrappers
    

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16. #AndroidDevDays
    Android / Java Unity / C#
    primitive types primitive types
    java.lang.String string
    java.lang.Object AndroidJavaObject
    java.lang.Class AndroidJavaClass
    java.lang.Runnable AndroidJavaRunnable
    java.lang.Proxy AndroidJavaProxy
    Provided Wrappers
    

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17. Two-way communication
    C# ↔ Java
    

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18. #AndroidDevDays
    C# → Java
    • AndroidJavaObject
    • Pure JNI (Java Native Interface)
    Java → C#
    • Unity Messaging
    • AndroidJavaProxy
    Two Way Communication
    

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19. #AndroidDevDays
    Sample Java class
    public class Speaker {
    private String name;
    public Speaker(String name) { … }
    public static Speaker copy(Speaker speaker) { … }
    public String askQuestion(String question) { … }
    }
    Java
    

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20. #AndroidDevDays
    C#
    var jSpeaker = new AndroidJavaObject(
    “com.zasadnyy.Speaker”, “Vitaliy”);
    var jClone = jSpeaker.CallStatic(
    “copy”, jSpeaker);
    var answer = jSpeaker.Call(“askQuestion”, “HDYD?”);
    AndroidJavaObject
    • Wrapper around java.lang.Object
    

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21. #AndroidDevDays
    C#
    // var jSpeaker = new AndroidJavaObject(
    // “com.zasadnyy.Speaker”, “Vitaliy”);
    IntPtr classID = jni.FindClass("com.zasadnyy.Speaker");
    IntPtr constructorID = jni.GetMethodID(classID,
    "", "(Ljava/lang/String;)V");
    IntPtr javaString = jni.NewStringUTF("Vitaliy");
    IntPtr objectID = jni.NewObject(classID,
    constructorID, javaString);
    "(Ljava/lang/String;)V"
    Pure JNI
    

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22. #AndroidDevDays
    B byte S short
    C char V void
    F float Z boolean
    I int Lclass; class
    J long [type> array of type
    JNI Cheatsheet
    

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23. #AndroidDevDays
    B byte S short
    C char V void
    F float Z boolean
    I int Lclass; class
    J long [type> array of type
    long myMethod(int n, String s, int[] arr)
    (ILjava/lang/String;[I>)J
    JNI Cheatsheet / Example
    

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24. #AndroidDevDays
    JNI is slooooow!
    Respect 16ms rule
    

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25. #AndroidDevDays
    Conclusion
    Use AndroidJavaObject:
    • Less boilerplate
    • Less error prone
    • Faster (caching)
    But:
    • JNI is more flexible
    • AndroidJavaObject has bugs
    

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26. #AndroidDevDays
    AndroidJavaObject Bugs *
    var result = javaObject.Call(TParam param);
    C#
    • we can’t pass string[] as TParam
    (NoSuchMethodException)
    • we can’t return null objects from Java (Exception:
    JNI: Init'd AndroidJavaObject with null ptr!)
    * Tested on Unity 5.0.1f1
    

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27. #AndroidDevDays
    C#
    • AndroidJavaObject
    • Pure JNI (Java Native Interface)
    Java → C#
    • Unity Messaging
    • AndroidJavaProxy
    Two Way Communication
    

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28. #AndroidDevDays
    Unity Messaging
    

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29. #AndroidDevDays
    UnityPlayer.UnitySendMessage(
    "GameController", "OnPushMessage", "New gift");
    Java
    Unity Messaging
    

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30. #AndroidDevDays
    Pros:
    • Quick to implement
    Cons:
    • Always 1 frame late
    • Only string parameters
    • Requires GameObject
    • Requires unity-classes.jar in classpath
    Unity Messaging
    

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31. #AndroidDevDays
    AndroidJavaProxy
    Java
    public interface IPushMessageListener {
    void onPushMessage(String message);
    }
    • Wrapper around java.lang.Proxy
    

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32. Java
    public interface IPushMessageListener {
    void onPushMessage(String message);
    }
    C#
    public class PushMessageListener : AndroidJavaProxy {
    public PushMessageListener() :
    base("com.zasadnyy.IPushMessageListener") { … }
    void onPushMessage(string message) { … }
    }
    AndroidJavaProxy
    

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33. #AndroidDevDays
    Pros:
    • Immediate result
    • No type restriction on parameters
    • No extra dependencies on Java side
    Cons:
    • Bug with null string parameter
    • Local reference table is limited to 512 entries
    AndroidJavaProxy
    

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34. Devil is in the details
    

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35. #AndroidDevDays
    Details
    • Unity is single threaded
    • Unity main thread != Android main thread
    • Implement equals() in all AndroidJavaProxy’ies
    • Differences between GameObject and Activity lifecycle
    • Keep calm and signal 11
    

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36. #AndroidDevDays
    Thank you!
    Presentation will be available at:
    v.zasadnyy.com/slides/
    Vitaliy Zasadnyy
    @zasadnyy
    

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