How do I define and use an ENUM in Objective-C

Question

I declared an enum in my implementation file as shown below  and declared a variable of that type in my interface as PlayerState thePlayerState  and used the variable in my methods  But I am getting errors stating that it is undeclared  How do I correctly declare and use a variable of type PlayerState in my methods    In the  m file   implementation View1Controller      typedef enum playerStateTypes                       PLAYER OFF              PLAYER PLAYING              PLAYER PAUSED           PlayerState    in the  h file    interface View1Controller   UIViewController        PlayerState thePlayerState    in some method in  m file   - void doSomethin   thePlayerState   PLAYER OFF

User · Answer

This is how Apple does it for classes like NSString:

In the header file:

enum {
    PlayerStateOff,
    PlayerStatePlaying,
    PlayerStatePaused
};

typedef NSInteger PlayerState;

Refer to Coding Guidelines at http://developer.apple.com/

User · Answer

Your typedef needs to be in the header file  or some other file that s  imported into your header   because otherwise the compiler won t know what size to make the PlayerState ivar   Other than that  it looks ok to me

User · Answer

In the  h   typedef enum       PlayerStateOff      PlayerStatePlaying      PlayerStatePaused   PlayerState

User · Answer

With current projects you may want to use the NS ENUM   or NS OPTIONS   macros   typedef NS ENUM NSUInteger  PlayerState            PLAYER OFF          PLAYER PLAYING          PLAYER PAUSED

User · Answer

Apple provides a macro to help provide better code compatibility  including Swift  Using the macro looks like this   typedef NS ENUM NSInteger  PlayerStateType      PlayerStateOff    PlayerStatePlaying    PlayerStatePaused      Documented here

User · Answer

I recommend using NS OPTIONS or NS ENUM  You can read more about it here  http   nshipster com ns enum-ns options   Here s an example from my own code using NS OPTIONS  I have an utility that sets a sublayer  CALayer  on a UIView s layer to create a border   The h  file   typedef NS OPTIONS NSUInteger  BSTCMBorder        BSTCMBOrderNoBorder       0      BSTCMBorderTop            1  lt  lt  0      BSTCMBorderRight          1  lt  lt  1      BSTCMBorderBottom         1  lt  lt  2      BSTCMBOrderLeft           1  lt  lt  3      interface BSTCMBorderUtility   NSObject     void setBorderOnView  UIView   view                  border  BSTCMBorder border                   width  CGFloat width                   color  UIColor   color    end   The  m file    implementation BSTCMBorderUtility     void setBorderOnView  UIView   view                  border  BSTCMBorder border                   width  CGFloat width                   color  UIColor   color           Make a left border on the view     if  border  amp  BSTCMBOrderLeft                   Make a right border on the view     if  border  amp  BSTCMBorderRight                   Etc      end

[iphone] How do I define and use an ENUM in Objective-C?

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