How to convert this NSTimeInterval line from Swift to Objective-C

Question

How to convert this into Objective-C ?

let date = NSDate(timeIntervalSinceReferenceDate: interval)

I tried this:

NSDate *date = [NSDate timeIntervalSinceReferenceDate: (interval)];

It generates an error of course.

Tells me: No known class method for selector timeIntervalSinceReferenceDate:

Also here is some context:

 NSTimeInterval interval = [[NSDate alloc]init].timeIntervalSinceReferenceDate + [NSDate weekInSeconds].doubleValue;
    NSDate *date = [NSDate timeIntervalSinceReferenceDate: (interval)];
    return [self isSameWeekAsDate:(date)];

Answer 1

timeIntervalSinceReferenceDate: is not a method implemented on the NSDate class. When bridging from Objective-C to Swift, Swift does some renaming with initializers.

In order to initialize an NSDate object in Objective-C with a reference date, you must call either the class method dateWith... or the instance method initWith...:

NSDate * const date = [NSDate dateWithTimeIntervalSinceReferenceDate: timeInterval];

or...

NSDate * const date = [[NSDate alloc] initWithTimeIntervalSinceReferenceDate: timeInterval];

I've added the const here to make this more closely match the Swift code with the let declaration.