Graphics Programs Reference
In-Depth Information
Figure 16.10 Changing the class of an entity
There is one problem: the
BNRItem
class already exists, and it does not inherit from
NSManagedObject
. Changing the superclass of the existing
BNRItem
to
NSMan-
agedObject
will require considerable modifications. Thus, the easiest solution is to re-
move your current
BNRItem
class files, have Core Data generate a new
BNRItem
class,
and then add your behavior methods back to the new class files.
In
Finder
, drag both
BNRItem.h
and
BNRItem.m
to your desktop for safekeeping.
Then, in
Xcode
, delete these two files from the project navigator. (They will appear in red
after you have moved the files).
Now, open
Homepwner.xcdatamodeld
again and select the
BNRItem
entity. Then,
select
New File...
from the
New
menu.
From the
iOS
section, select
Core Data
, choose the
NSManagedObject subclass
option,
and hit
Next
. When prompted to save, check the box for
Use scalar properties for primit-
ive data types
.
Xcode
will generate two new
BNRItem.h
and
BNRItem.m
files. Open
BNRItem.h
and see what Core Data has wrought. Change the type of the
thumbnail
property to
UIImage
and add the method declaration from the previous
BNRItem
.
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
@interface BNRItem : NSManagedObject
@property (nonatomic, strong) NSString * itemName;
@property (nonatomic, strong) NSString * serialNumber;
@property (nonatomic) int32_t valueInDollars;
