如何保存和读取NSObject

Question

I have two NSObject's.

@interface Car : NSObject{
     @property (strong) NSSet *cars;
}

and

@interface Model : NSObject{
     @property (strong) UIImage *picture;
     @property (strong) NSString *name;
}

Basically the object Car has a NSSet cars and each object of the NSSet cars has the properties picture and name.

How can I relate this two NSObject's and how can I save a string or image to the Car NSSet using the properties of the Model NSObject. Thanks.

Answer 1

For easy adding or removing, your " cars " property should be declared as a NSMutableSet .

And assuming your single Car object is named " listOfCars ", here is one way to do what (I think) you are trying to do:

Model * newModel = [[Model alloc] init];
if(newModel)
{
    newModel.picture = [UIImage imageNamed: @"Edsel.jpg"];
    newModel.name = @"Ugly Car";

    [listOfCars.cars addObject: newModel];
}

And, in your Car .m file, do something like this:

- (id) init
{
    self = [super init];
    if(self)
    {
        _cars = [[NSMutableSet alloc] init];
    }
    return(self);
}

The init method is the only place you should be referring to the underlying variable for your " cars " property. Everywhere else it should be " listOfCars.cars " or " self.cars " if you're referring to the cars set from within the Car object.