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Structure of a Unity Xcode Objective-C project type

Understand the structure of a Unity Xcode Objective-C project type.
Read time 5 minutesLast updated 13 days ago
When you build a Unity Xcode Objective-C project for the iOS platform, Unity creates a folder that contains an Xcode project. You need to build and sign this project before you deploy it on a device or distribute it on the App Store.
Note
Use the Xcode project type Player setting to build an Objective-C or Swift Xcode project type. For information on the structure of a Unity Xcode project built with Swift, refer to Structure of a Unity Xcode Swift project type.
Every generated Unity iOS Xcode project has the following structure and targets:

Unity iOS Xcode project structure

Note
This image is for reference purposes only. Your project structure might look different than this example image depending on the version of Xcode you're using.
The Xcode project includes both the 
.xcodeproj
project file and framework links that only appear in the Xcode project navigator. Apart from the default folders, you can create custom folders to add custom files as required.
Note
You can modify a generated Xcode project using Xcode.PBXProject.

Project targets

  • Unity-iPhone: A thin launcher part that runs the UnityFramework. It includes the 
    MainApp
    folder and app representation data such as Launch Screens, 
    .xib
    files, icons, data, and 
    Info.plist
    files. The Unity-iPhone target has a single dependency on the UnityFramework target.
  • UnityFramework: The target that produces the 
    UnityFramework.framework
    bundle. It includes the Unity runtime, 
    Classes
    , 
    UnityFramework
    , and 
    Libraries
    folders, along with dependent frameworks. 
    UnityFramework
    folder includes privacy manifest file (PrivacyInfo.xcprivacy), a consolidated privacy manifest file for Unity runtime, Unity plug-ins, packages, and your project.
  • GameAssembly: A container for your C# code translated as C++ code. To build it, Xcode uses the IL2CPP tool that Unity includes in every generated Xcode project. The build produces:
    • libGameAssembly.a
      : A static library that contains all the project’s managed code, cross-compiled to C++, and built for iOS.
    • il2cpp.a
      : A static library that contains the IL2CPP runtime code to support your managed code.
Note
Use PBXProject.GetUnityFrameworkTargetGuid() to get the globally unique identifier (GUID) for the UnityFramework target and PBXProject.GetUnityMainTargetGuid() to get the Unity-iPhone target GUID.

Classes folder

The 
Classes
folder contains code that integrates the Unity runtime and Objective-C. Unity stores the entry points of the application in the 
main.mm
and 
UnityAppController.mm/h
files inside this folder. You can create your own 
AppDelegate
derived from 
UnityAppController
, or, if any of your plug-ins include 
AppController.h
, you can include 
UnityAppController.h
instead. If your 
Plugins/iOS
folder includes 
AppController.mm/h
, you can merge and rename them.
The code in this folder doesn’t change often, and you can place custom classes here. If you select the Append mode, Xcode preserves changes to this folder between builds. However, this function doesn’t support multiple build targets and requires a fixed structure of the 
Libraries
folder.
Unity’s internal profiler is fast and unobtrusive, and feeds basic information about:
  • Which subsystem is taking most of the frame time.
  • The .NET heap size.
  • Garbage collection (GC) event count and duration.

Data folder

This folder contains your application’s serialized assets and .NET assemblies (
.dat
files). The 
machine.config
file sets up various .NET services such as security and WebRequest. Xcode refreshes the contents of this folder with every build. You shouldn’t make any changes to it.
By default, the 
Data
folder’s Target Membership is the Unity-iPhone target, and Unity runtime searches for it in the 
mainBundle
. To change the default bundle where Unity runtime looks for the 
Data
folder, call 
setDataBundleId: "com.my.product"
on the UnityFramework instance before you call one of the run functions. For example, if you want to have 
Data
together with the UnityFramework call, use 
setDataBundleId: "com.unity3d.framework"
and set the Target Membership to UnityFramework.
Note
On-Demand Resources are supported only when the 
Data
folder is a part of the Application target and not a part of the 
UnityFramework
target.

Data folder with the Target Membership set to UnityFramework.

Note
This image is for reference purposes only. Your project structure might look different than this example image depending on the version of Xcode you're using.

Frameworks folder

The Frameworks folder contains 
UnityRuntime.framework
, which contains the Unity Runtime static frameworks and plug-in types library for device and simulator.

Libraries folder

The contents of the Libraries folder are refreshed with every build. You shouldn’t make any changes to it.

Graphics files

Icons and splash screens (
.png
files) are located in asset catalogs in the 
Unity-iPhone
folder. Unity automatically manages these files. Launch screens, their XML Interface Builders (
.xib
files), and Storyboard files are stored in the project’s root folder. You can configure these files in the
Player Settings

?

window (menu: Edit >
Project Settings

?

> Player Settings). Make sure the custom launch images that you create adhere to Apple’s Human Interface Guidelines.

Property list (.plist) file

You can manage the 
Info.plist
file within the Unity-iPhone target (accessed via 
mainBundle
) from Unity’s Player Settings window (menu: Edit > Project Settings > Player Settings > Other Settings > Identification). Unity updates this file rather than replacing it while building the Player. Don’t make changes to it unless you need to.
The 
/UnityFramework/Info.plist
file, accessed via 
bundleWithIdentifier:@"com.unity3d.framework"
, is a part of 
UnityFramework
. You can keep project specific values in this file instead of the 
Info.plist
file of the 
mainBundle
. This makes sure that you can still get these values if 
UnityFramework
is moved into another application, for example, when using Unity as a Library.
Note
You can also manage the 
Info.plist
file using the PlistDocument API. For more information, refer to PlistDocument.

Additional resources