vgonisanz vgonisanz - 2 months ago 17
Objective-C Question

How to initialize an Objective C struct in constructor?

I´m using a struct on Objective C to store some data, something like this:



@interface Interface : NSObject
{
// my Data
struct Data
{
__unsafe_unretained BOOL isInit;
__unsafe_unretained BOOL isRegister;
__unsafe_unretained NSString* myValue;

// Data() : isInit(false), isRegister(false), myValue(@"mYv4lue") {} // Constructor doesnt work
};

struct Data myData; // Create Struct

}



But I can't compile with a constructor. I want the values take some default value when I create the Struct.

How can I do this?

Answer

Structs don't have initializers, if you want to create a struct with a particular set of values you could write a function that returns creates and initialises it for you:

For example

struct Data {
        BOOL isInit;
        BOOL isRegister;
        NSString* myValue;
};

Data MakeInitialData () {
    data Data;
    data.isInit = NO;
    data.isRegister = NO;
    data.myValue = @"mYv4lue";

    return data;
}

now you can get a correctly set up struct with:

Data newData = MakeInitialData();

A note, though; you seem to be using ARC, which doesn't work well with structs that have object pointers in them. The recommendation in this case is to just use a class instead of a struct.