How to import objective-c framework into a swift framework project?

Import Obj-C Framework To Swift Framework

Recently manager asked me to export some of my apps functions into a dynamic framework instead of keep them a whole app. So I was fighting on extracting the code into a framework project. When I extract the map, I met some issue. The map sdk we are using is written in objc. If I am importing objc framework into a swift project, normally I would create a bridge header and boom, I can use it in Swift. However, bridge header is now how things works when creating a dynamic framework.

How to

So how to import Obj-C framework into Swift framework?

Import Framework

First import the framework. Download the .framework file, put in under the $(PROJ_DIR)/lib. Open Xcode, Switch to Build Phases -> Link Binary With Libraries and add downloaded framework.

You can also use Cocoa-Pods to import the framework.

Create Framework Module Map File

Go to the folder where the framework is added. For example, if you install the framework using cocoa-pods, then it should be located at:

1	"$(SRCROOT)/Pods/FrameworkName/"

Inside that folder, there should be a file called FrameworkName.framework. Create a file called module.modulemap at the same level. Inside module.modulemap: (second header include is optional). Include anything that you need.

module Framework {
    header "Framework.framework/Versions/A/Headers/Framework.h"
    header "Framework.framework/Versions/A/Headers/OtherFrameworkHeader.h"

    export *
}

Create Private Module Map File

Now go to $(SRCROOT) directory, create target.private.modulemap file. Inside file, write:

1
2
3

module TargetPrivate {
    export Framework
}

The module name can be target name + private. When export, write the framework module name.

Project Settings

After creating all the map module file, go to the target -> Build Settings, search module, find Private Module Map File, enter the path for the target.private.modulemap file. It is usually be:

1	$(SRCROOT)/target.private.modulemap

Now search for "import" find Import Paths under Swift Compiler - Search Paths, enter the root directory for private module map. It is usually be:

1	$(SRCROOT)

Import In Code

Now in code, wherever you need to use the library, you can use #import framework. I know its an objective-c framework, because you setup the module map, you can import them directly in .swift now. After import the file that expose is those you have headers inside module framework file.

You can also import that in umbrella header using #import <Framework/Framework.h>. If you did that inside umbrella header then no need to import for individual swift files anymore.

My Research

Here is a list of research I did. It took me some time try different things.

Understand Modular Framework

In order to understand how to solve the problem, we need to understand what the modular framework is. There are many awesome blog posts exists on that topic. Here is a list that helped me understanding.

Understand Allow Non-Modular Includes

If you ever see error message of non-modular header inside framework module, try to understand this answer.

[Optional] More Research Resources

Here is a list of links that related to this issue. Not all of them are helpful, but I decided to bookmark all of them just in case.

Update

Here is an update. Previously my understanding is wrong. My previous understanding is only partial and the solution does not help to solve the issue.

So now here is some add-on that may help me understand modular well. This modular framework creating and using them is mentioned before. Read it again carefully will understand the basic knowledge of modular file.

Here is clang documentation on private modular files.

This github project gives an example on how to include objective-c framework inside a swift framework project. It is very useful and gives a lot of hints.

Import Third-Party Objective-C Framework into Swift Framework Project