Importing static library in swift project

Question

Create a static library in objective c and c and trying to import in swift project. followed this link

Getting this error while building application

Undefined symbols for architecture arm64:
"_OBJC_CLASS_$_XYZ", referenced from: objc-class-ref in ViewController.o ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

Using:

Xcode10.2

Swift 4.2

Answer 1

Ok, let's do it from scratch step-by-step just to recall that it is possible (used Xcode 11.2, sorry - no 10.2, but I did this even before, so sure nothing changed since then)

1) Create new project form template

iOS > Single View App > Sample (Swift/Storyboard) > Next > Create > Build > Ok

2) Create static lib from template

Project Navigator > Sample > Add Target > iOS > Static Library > Calculator (Objective-C) > Finish

3) Add something meaningful to Calculator

Update Calculator.h & Calculator.m with following ...

@interface Calculator : NSObject
+ (NSString *)calculatedValue;
@end

@implementation Calculator
+ (NSString *)calculatedValue {
    return @"1 + 1 = 5";
}
@end

Switch active schema to Calculator > Build > Ok

4) (!!! Very important step) Prepare Swift-ObjC bridge in main target

I prefer that Xcode do this, so... switch back active schema to Sample app

File > New > Cocoa Touch Class > Stub (Objective-C)

Next > (Make sure target is Sample checked) > Create

Create Bridging Header (This is it! - actually internally it does more) > Remove Stub.h/m (as they don't need for us)

5) Open Sample-Briding-Header.h and into it #import "Calculator.h"

6) Add library to main app target

Project Navigator > Sample > Target Sample > General > Section "Frameworks, Libraries... > + > select libCalculator.a

Actually, that's it - now it possible to use Objective-C classes from static library in main Swift-based application

7) Simple demo manipulations... create UILabel in View Controller Scene of Main.storyboard and create outlet to it in ViewController.swift, set string generated in library to UILabel.text property

class ViewController: UIViewController {

    @IBOutlet weak var results: UILabel!
    override func viewDidLoad() {
        super.viewDidLoad()

        results.text = Calculator.calculatedValue()
    }
}

8) Build & Run > OK (observe result of integration)