ARC unavailable methods in Swift

问题

I was able to see an interesting case using Estimote nearables SDK

They have a class ESTNearable with property called zone.

// ENUM
typedef NS_ENUM(NSInteger, ESTNearableZone ) {
   ESTNearableZoneUnknown = 0,
   ESTNearableZoneImmediate,
   ESTNearableZoneNear,
   ESTNearableZoneFar,
};

// CLASS
@interface ESTNearable : NSObject <NSCopying, NSCoding>
// ... 
@property (nonatomic, assign, readonly) ESTNearableZone zone;
// ...
@end

So when I try to use this method in Swift, compiler fails with that error:

As I understand there is some kind of compiler bug and for some reason it believes that I want to use old zone method from NSObject - (struct _NSZone *)zone OBJC_ARC_UNAVAILABLE; I can use other specific properties of that class without any problems.

As I use an SDK I can not change the name of the zone method. I believe I can write some kind of obj-c category, add some new method there, which will return value of original one, but I do not want to add obj-c classes in my project.

Is there any possibility to call this method from swift as I believe correct zone method will be called for class instances?

Thanks in advance!

回答1:

Here I found the same question. I answered more deeply there. I could not find something more good, so I went ahead with my old assumptions.

I Added this category to Bridging Header. It worked fine.

#import <EstimoteSDK/EstimoteSDK.h>

@interface ESTNearable (Ex)

/// Solving the compiler problem that "zone" method is unavailable in Swift
@property (readonly) ESTNearableZone nearableZone;

@end

// Implementation

@implementation ESTNearable (Ex)

- (ESTNearableZone)nearableZone
{
    return self.zone;
}

@end

After that I just used nearableZone method in Swift

var zone = someNearable.nearableZone

来源：https://stackoverflow.com/questions/30599486/arc-unavailable-methods-in-swift