Using Java or Kotlin source files as plug-ins

Unity supports plug-ins for Android written in Java or Kotlin. This functionality allows you to add .java or .kt files into your Unity Project and they are compiled when you build an Android player. Previously you had to precompile these files as an android library.

Gradle is the only build system that supports this feature so use Gradle as your build system.

To compile the source files as a plug-in:

1. Open the Unity Editor.
2. Select the Project to add the plug-in to.
3. In the Projects window, select the Assets folder and create a folder for your plug-in.
4. Drag and drop your source files into the folder.
5. Select each of the files.
6. In the inspector window, under Select platforms for plugin, verify that only Android is selected.
7. Build your Project.

Note: You can place your source files in any folder in your Project except in special use locations such as subfolders under Assets/Plugins/Android. If you place files in these locations, the Unity Editor will not display the plug-in inspector. For additional information, see AAR plug-ins and Android Libraries.

Use the AndroidJavaObject class to call methods in your plug-in. For additional information see, the “Using your Java plug-in from C# scripts with helper classes” section in JAR plug-ins.

Symlink Sources

To enable direct referencing of the Java and Kotlin files in the exported gradle project and eliminte the need to manually copy the edited Java and Kotlin files from the exported gradle project to the Unity Project, enable Symlink Sources in the Build Settings window.

• 2018–12–08 Added Symlink Sources option.
• 2018–11–29 Page amended with editorial review
• 2018–09–07 Page published with editorial review
• Added plug-in support in 2018.2