相关疑难解决方法(0)

我已经阅读了NSCopying文档,但我仍然不确定如何实现所需的内容.

我的班级Vendor:

@interface Vendor : NSObject 
{
    NSString        *vendorID;
    NSMutableArray  *availableCars;
    BOOL            atAirport;
}

@property (nonatomic, copy) NSString *vendorID;
@property (nonatomic, retain) NSMutableArray *availableCars;
@property (nonatomic, assign) BOOL atAirport;

- (id)initFromVehVendorAvailsDictionary:(NSDictionary *)vehVendorAvails;

@end

的Vendor类有称为对象的数组Car.

我的Car目标:

@interface Car : NSObject 
{
    BOOL            isAvailable;
    NSString        *transmissionType;
    NSMutableArray  *vehicleCharges; 
    NSMutableArray  *fees; 
}

@property (nonatomic, assign) BOOL isAvailable;
@property (nonatomic, copy) NSString *transmissionType;
@property (nonatomic, retain) NSMutableArray *vehicleCharges;
@property (nonatomic, retain) NSMutableArray *fees;

- …

这可能是一个简单的问题,但为什么在我的课堂上实施NSCopying协议,我得到zone == nil

- (id)copyWithZone:(NSZone *)zone
{
    if (zone == nil)
        NSLog(@"why this is allways nil");

    (...)
}

对于带有对象的复制数组,使用此方法调用此方法.

[[NSArray alloc] initWithArray:myArray copyItems:YES]];