I am trying to integrate this https://github.com/gareth-cross/kalman-ios project with my own Swift project in Xcode.
When building the project I receive 2 errors:
kalman-ios/matrix.hpp:28:10: error: 'cmath' file not found
failed to emit precompiled header
'/Users/.../Build/Intermediates.noindex/PrecompiledHeaders/Tron-iOS-Bridging-Header-
swift_J9ENU1M0P5CE-clang_M49XZJR5TLTE.pch'
for bridging header '/Users/.../Filter/Tron-iOS-Bridging-Header.h'
My project is purely Swift, and the kalman-ios project is a mixture of ObjC and ObjC++.
My bridging header file is:
//
// Use this file to import your target's public headers that you would like to expose to Swift.
//
#import "KFEstimator.h"
For more context, the kalman-ios project is structured as:
KFEstimator.mm makes calls to AttitudeESKF.cpp makes calls to matrix.cpp
My initial thought was the cmath file error was the cause for the bridging header error. But I have almost no experience outside Swift and don't know how to go about fixing it. Up until yesterday, I wasn't even aware that you could use ObjCPP.
Any help is appreciated!
I have solved the issue. I was mistaken and believed that the repository was Objective-C making calls to Objective-C++.
It was actually all Objective-C++.
I was able to make direct calls to the Objective-C++ functions by following this video guide.
Related
Spent a lot of time on finding the solution on google and SO but no success. Very hope someone can point out what can be the problem.
So I have objc+swift project. I have a Bridging Header file with imports of Objc header files that I need to use in Swift.
To explain the issue I'll share 2 scenarios. In the 1st scenario, everything works fine. In 2nd it shows an error.
Please note: Both scenarios have the same code base.
Scenario 1. Doesn't work, shows error.
I open the project.
Hard Clean it.
Build
Shows error: 'myProjectName-Swift.h' file not found
It also shows such error:
failed to emit precompiled header
'/Users/tungfam/Library/Developer/Xcode/DerivedData/myProjectName-ctxxkwqtckhvyoawavmuzmdxqaml/Build/Intermediates.noindex/PrecompiledHeaders/myProjectName-Bridging-Header-swift_1UP5PCPCLBPHP-clang_18PVO5108TD8S.pch'
for bridging header
'/Users/tungfam/Developer/myProjectName/myProjectName/App/myProjectName-Bridging-Header.h'
Scenario 2. How to make it work.
I take the same code from Scenario 1.
Hard Clean it
Comment the imports in Bridging Header file
Comment the Swift code where I used Obc files (that were declared in bridging header that I just commented in previous step)
I build the project. It succeeds.
Since some parts in the app are broken cuz I commented stuff. I uncomment the imports in Bridging Header file and the Swift code where I used Objc classes.
Run again (without hard clean) and everything works.
Will really appreciate any help on this issue. Please share anything you think that may help to fix this issue.
I'm using Xcode 10.0; Swift 4.2
UPDATE1: I think it has to do something with the 2nd error I placed above. Maybe it can't generate that bridging file.
UPDATE2: I read something like: "If you are importing the Objc file named ABC into Bridging Header. And if this ABC imports into himself the file myProjectName-Swift.h. Then this case may have some problems. Do you think it can be true?
You must not use #import "ProjectName-Swift.h" in the header files.
If you need Swift classes or protocols in the Obj-C code, you may forward declare them in the related Obj-C header. Here's more information about that:
When declarations in an Objective-C header file refer to a Swift class or protocol that comes from the same target, importing the generated header creates a cyclical reference. To avoid this, use a forward declaration of the Swift class or protocol to reference it in an Objective-C interface.
// MyObjcClass.h
#class MySwiftClass;
#protocol MySwiftProtocol;
#interface MyObjcClass : NSObject
- (MySwiftClass *)returnSwiftClassInstance;
- (id <MySwiftProtocol>)returnInstanceAdoptingSwiftProtocol;
// ...
#end
Also, please note, you may have issues with importing Swift Enums and Protocols and Classes into ObjC, so you may need to explicitly define items which you want to be available to ObjC code with #objc keyword.
And you won't be able to use Swift structs in Obj-C.
From Swift to Objective C you just have to use #import "ProjectName-Swift.h" on your Objective C classes that needs access to Swift code. There's no need to add on the bridging header file. For the other way Objective C to Swift then you need to declare in the bridging header file.
I am trying to create a Swift wrapper for the FIT C++ libFitSdkCppiOS.a library but don't really know how to set things up with the mix of C++, Objective-C and Swift code.
Here is what I have done so far:
1. Created a new target for the FITFramework
2. Copied the libFitSdkCppiOS.a library and the associated cpp header files into the targets folder in Xcode
3. Because you can't use a Bridging-Header file in Frameworks I am trying to figure out how what to do next.
I have seen a few posts about something called an umbrella header but have no idea what that is or what needs to be in it to get this to work. Can someone please explain step by step what I need to do to create this Swift Wrapper and package it up as a framework that can be used by other projects.
Is the umbrella header the main framework header file, in this case the one called FITFramework.h ?
If not how do I create an umbrella header file and where does it need to be?
What should be in the umbrella header file?
FITFramework.h
//
// FITFramework.h
// FITFramework
//
// Created by xxxx xxxxxxx on 7/6/18.
//
#import <UIKit/UIKit.h>
//! Project version number for FITFramework.
FOUNDATION_EXPORT double FITFrameworkVersionNumber;
//! Project version string for FITFramework.
FOUNDATION_EXPORT const unsigned char FITFrameworkVersionString[];
// In this header, you should import all the public headers of your framework using statements like #import <FITFramework/PublicHeader.h>
EDIT:
1. How do I expose the Objective-C classes to Swift without using a Bridging-Header file ?
There are a few articles that mention the use of a module.map file but this seems to be to expose the C headers rather than the Objective-C headers to the Swift wrapper function
OK I figured it out - and it was hard to find any good or accurate guides. I will write it up in more detail elsewhere and add a link at some point.
In the meantime - assuming your framework is call XXXFramework - you need to:
create a XXXFrameworkPrivate subdirectory in the XXXFramework folder with a module.modulemap file in it
add the private headers to the module.modulemap file like so
module FitFrameworkPrivate {
header "../XXX.h"
header "../YYY.h"
header "../ZZZ.h"
export *
}
create a XXX.xcconfig file with the following line
SWIFT_INCLUDE_PATHS = $(SRCROOT)/XXXFramework/XXXFrameworkPrivate
set the project configuration to use this config file for both debug and release
add this line to your Swift classes
import XXXFrameworkPrivate
Basically this allows Swift classes to import the headers from the module.modulemap file instead of using a Bridging-Header file which can't be used in a Framework.
Watch out though - I have callbacks between the C++ classes, the Objective-C classes and the Swift classes and this creates a problem if your public class uses a protocol to communicate with one of the private Obj-C classes. To avoid that add another public Swift class that talks to the Swift wrapper and only have that one public.
If anyone has a better way of doing it please let me know.
Thanks a lot! This answer was very useful to me as I had similar issue (to integrate the c fit sdk instead of the c++ fit sdk into a swift framework for macOS and iOS apps)
I'll just add the follow step I had to do, in case it helps someone:
When using the framework in a app that used Pods, I wasn't able to include the "Private" framework (necessary because it contains the c constant converted to swift constant like FIT_MESG_XXX) and the xcconfig are set by the Pods framework. Editing the Pods xcconfig worked, but clearly bad.
Eventually, I figured out you can just create a new xconfig with a #include and use that in the external app where you want to use like so (this is separate from the xcconfig you need to build the framework)
#include "../Pods/Target Support Files/Pods-iOSorMac/Pods-iOSorMacOSApp.debug.xcconfig"
SWIFT_INCLUDE_PATHS="$(SRCROOT)/fit-sdk-swift/RZFitFile/sdk" "$(SRCROOT)/fit-sdk-swift/RZFitFile/src"
I have an umbrella header called
MyApp-Swift.h
I've imported the following class "AFHTTPSessionManager.h" in the umbrella header.
I made the umbrella header public in build phases and I also made sure to set Define modules to yes.
However, in my swift framework I am still getting the following error
Use of undeclared type 'AFHTTPSessionManager'
I don't know why this is continuing. I thought swift would automatically pick up my Objective-C import. Any tips or suggestions are appreciated.
I tried following this source
https://developer.apple.com/library/content/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html#//apple_ref/doc/uid/TP40014216-CH10-XID_82
,but it didn't work for me. This is very fusterating.
This is the swift code that causes the error.
import Foundation
class MyApp {
private var manager: AFHTTPSessionManager?
}
The thing is, brigding header doesn't work for Framework targets. Solution is to create module map target to build module map for needed ObjC framework.
Here is example for CommonCrypto: https://stackoverflow.com/a/42852743/1840136; in your case difference should be that script line
header "${SDKROOT}/usr/include/CommonCrypto/CommonCrypto.h"
will be replaced with path to AFNetworking headers (I'm not sure if you're placing 3rd party libraries just within project or getting from pods, so check by yourself).
I must have started from scratch about 4 times already. I've followed the solutions listed below but I still have an issue (which I think has something to do with the bridging header file).
Note: I have tried manually creating the bridging header as well as the automated solution Xcode offers when you drag some Objective-C files into a Swift project.
Swift Bridging Header import issue
Connect Objective C framework to Swift iOS 8 app (Parse framework)
Here are the main errors I am seeing. I've tried moving the header file up a level/down a level and it still claims to not see it. Everything is currently where Xcode put it when I selected "Yes" when prompted to created the bridging header automatically. You can also see the full contents of my bridging header.
The "Cannot find protocol declaration for NSObject" error usually refers to circular references problems.
I'm wondering why you put all those standard Apple frameworks in the bridging header? This might be the problem. This special file is supposed to "bridge" Swift and Objective C worlds together, so if you've already referenced and linked your app against those frameworks in your Swift code, you shouldn't need to do it again in the bridging header.
Try to remove all Apple-provided frameworks from your bridging header and only leave the specific ones (IBM....h), and see if it works?
If it doesn't, then start with Foundation/Foundation.h only...
I have a framework with Swift and Objective-C in it. I have the statement at the top of my Objective-C class #import "MyFrameworkHeader.h" which I thought would expose my swift code to my Objective-C class however the compiler still says the symbols don't exist, how can I expose my Swift classes to my Objective-C classes within the same Framework?
Ugh, after smacking my head for a few hours then finally posting this question, within a few minutes I found the answer:
https://developer.apple.com/library/ios/documentation/Swift/Conceptual/BuildingCocoaApps/MixandMatch.html#//apple_ref/doc/uid/TP40014216-CH10-XID_82
Under the header: "Importing Swift into Objective-C"
To get Objective-C to register your swift code you should go into your build settings and then see/set your project name, also see if the compatibility header option is checked to yes.
after that is set just go into your file and type #import "-Swift.h". I don't think you can import individual files with swift and Objective-C, you import all of your swift files at once. It's important that you make sure all of your swift files have no errors or you will get an error about this header not being defined. You might have to build your project with no errors for the file to get generated at least once.
I think what you're looking for is a Bridging Header.
This is a file that you import your Objective-C headers into that get exposed to Swift.
There are 2 ways to make one (as far as I know):
The easiest way, in my opinion, is to add an existing Obj-C file to your swift project, or vice-versa. Xcode should ask you if you want to automatically configure a bridging header. Choose yes, and Xcode should make a file called something like 'project name'-bridging-header.h. In this file, import your files, so #import "MyFrameworkHeader.h" should do it.
Make your own empty file with File > New File (Cmd+N) > Source > Header File. Call it whatever, and import your files like in the previous one. Before it will work, you have to enter the name of your bridging header file into a field in your Project Settings (In the first option, Xcode will do it for you).