Using non NS_ENUM objective-C enum in swift

Question

I am using the wahoo fitness API and it defines the following objective-C enum:

typedef enum
{
    /** No active connection. */
    WF_SENSOR_CONNECTION_STAT         


        

Answer 1

The workaround to use .value to get the underlying integer doesn't work anymore as of Beta 4, as you said.

Unfortunately an enum is not transferrable to Swift from Objective-C, it needs to be an NS_ENUM.

I have the same setup as you in a project where I need the enum from an Objective-C framework and use it in Swift.

The workaround I did was to create an Objective-C category that contains an NS_ENUM and there I transfer the values from the framework enum to my own NS_ENUM.

Import the category in your bridging header and you should be able to use the enum as you normally would do.

Something like this:

typedef NS_ENUM(NSUInteger, ConnectionStatus) {
    ConnectionStatusIdle
}

- (ConnectionStatus)connectionStatus {
    if [self getConnectionStatus] == WF_SENSOR_CONNECTION_STATUS_IDLE {
        return ConnectionStatusIdle
    }
}

Then you should be able to use it like this:

switch myObject.connectionStatus() {
    case .Idle:
        // do something
        break
}

Answer 2

C-style enums import in Swift like UInt32. So you can do something like:

let state = unsafeBitCast(WF_SENSOR_CONNECTION_STATUS_IDLE, UInt32.self)
if state == unsafeBitCast(WF_SENSOR_CONNECTION_STATUS_IDLE, UInt32.self) {
    //do something
}

Upd: In Swift 2.1 (Xcode 7.1 beta 2) all C-style enums conforms Equatable and you can now use it like:

let state = WF_SENSOR_CONNECTION_STATUS_IDLE
if state == WF_SENSOR_CONNECTION_STATUS_IDLE {
    //do something
}

Profit :)

Answer 3

Here is the final complete solution:

WFSensorConnection+SensorConnectionEnumCategory.h

:

#import <Foundation/Foundation.h>

#import <WFConnector/WFConnector.h>

@interface WFSensorConnection (SensorConnectionEnumCategory)

typedef NS_ENUM(NSUInteger, ConnectionStatus) {
    ConnectionStatusIdle,
    ConnectionStatusConnecting,
    ConnectionStatusConnected,
    ConnectionStatusInterrupted,
    ConnectionStatusDisconnecting
};

- (ConnectionStatus) swift_connectionStatus;

@end

---

WFSensorConnection+SensorConnectionEnumCategory.m

:

#import "WFSensorConnection+SensorConnectionEnumCategory.h"

@implementation WFSensorConnection (SensorConnectionEnumCategory)

- (ConnectionStatus) swift_connectionStatus{
    if ( [self connectionStatus] == WF_SENSOR_CONNECTION_STATUS_IDLE ){
        return ConnectionStatusIdle;
    } else if ( [self connectionStatus] == WF_SENSOR_CONNECTION_STATUS_CONNECTING ){
        return ConnectionStatusConnecting;
    } else if ( [self connectionStatus] == WF_SENSOR_CONNECTION_STATUS_CONNECTED ){
        return ConnectionStatusConnected;
    } else if ( [self connectionStatus] == WF_SENSOR_CONNECTION_STATUS_DISCONNECTING ){
        return ConnectionStatusDisconnecting;
    } else if ( [self connectionStatus] == WF_SENSOR_CONNECTION_STATUS_INTERRUPTED ){
        return ConnectionStatusInterrupted;
    }
    return 0;
}

@end

---

Bridging-Header.h

:

#import "WFSensorConnection+SensorConnectionEnumCategory.h"

---

Usage:

var sensorConnection: WFSensorConnection?
var connState : ConnectionStatus = ConnectionStatus.Idle
connState = sensorConnection!.swift_connectionStatus()
switch connState {
    case ConnectionStatus.Idle:
...
}

Answer 4

Note that there is a CoreFoundation type that is similar to NS_ENUM called CF_ENUM. I've used it on my framework that is mainly C. And yes, Swift does translate it to a Swift enum.

There is also something similar for NS_OPTIONS called CF_OPTIONS.