How to import and use Swift Pod Framework in Objective-C Project

Question

I've been trying to checkout CocoaPods new framework setup to get some Pods going and I'm having trouble using the Swift one's in my Objective-C project.

First things first, this is CocoaPods prerelease 0.35, you can read about how to use and install it here.

Here's my current Podfile:

source 'https://github.com/CocoaPods/Specs.git'

platform :ios, '8.0'

pod 'MBProgressHUD'
pod 'SLPagingViewSwift'

MBProgressHUD is a common spinning indicator, and SLPagingViewSwift is a random project I found by typing Swift into the cocoapods search. Here's the ViewController.m In my project:

#import "ViewController.h"

@import SLPagingViewSwift;
@import MBProgressHUD;

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    
    // Works just fine
    MBProgressHUD *hud = [[MBProgressHUD alloc] initWithView:self.view];
    [self.view addSubview:hud];
    [hud show:YES];

    // Causes Error -- Won't build
    SLPagingViewSwift *sl = [[SLPagingViewSwift alloc] init];
}

@end

Here's the SLPagingViewSwift declaration:

class SLPagingViewSwift: UIViewController, UIScrollViewDelegate {

As you can see, it inherits from UIViewController, so it shouldn't be a problem to just allocate it and initialize it. If I add the file separately as just a file, the above code runs just fine. I know it works.

tl;dr

How can I use a pure Swift Framework created by CocoaPods in a pure Objective-C class?

TroubleShooting

Mostly I've been trying various imports. Apple recommends the @import style here

But I have been trying multiple other varieties:

// Compiler Error
#import <SLPagingViewSwift/SLPagingViewSwift.h>

// Builds Fine -- Doesn't Work
#import <SLPagingViewSwift/SLPagingViewSwift-Swift.h>
#import "SLPagingViewSwift-Swift.h"

I've also been trying a few other Swift libraries from time to time to see if I could make anything click.

I don't see anything on the Cocoapods issues that can help this, I also didn't find anything in their blog / release stuff.

Note

If I add the SLPagingViewSwift.swift file separately to the project the old fashioned way, it works just fine.

Answer 1

I think you have to declare the swift class as public, otherwise it is treated as an internal class and can be only be seen within the same module, and this could be the reason why adding it to the same project as files work, but as a framework doesn't. Other thing that occurs to me is that the framework may need to add @objc in front of the class declaration so that it can be seen within objective-c classes. Also reading Apple's guide of Mix and Match between objective c and swift it says that when you import an external framework, you need to make sure the Defines Module build setting for the framework you’re importing is set to Yes. Have you checked with any of those options?