Reputation: 31
I was trying a new API in iOS12:
[NSKeyedArchiver archivedDataWithRootObject:<#(nonnull id)#> requiringSecureCoding:<#(BOOL)#> error:<#(NSError * _Nullable __autoreleasing * _Nullable)#>]
What I was trying to do is very simple, archive a custom class, here is the code:
A class named Cat:
@interface Cat : NSObject <NSCoding>
@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) NSInteger age;
+ (void)saveThisCat:(Cat *)cat;
+ (Cat *)getThisCat;
@end
@implementation Cat
- (void)encodeWithCoder:(nonnull NSCoder *)aCoder {
[aCoder encodeObject:self.name forKey:@"name"];
[aCoder encodeInteger:self.age forKey:@"age"];
}
- (nullable instancetype)initWithCoder:(nonnull NSCoder *)aDecoder {
if (self = [super init]) {
self.name = [aDecoder decodeObjectForKey:@"name"];
self.age = [aDecoder decodeIntegerForKey:@"age"];
}
return self;
}
+ (void)saveThisCat:(Cat *)cat {
NSError *error = nil;
NSString *docPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
NSString *filePath = [docPath stringByAppendingPathComponent:@"cat.plist"];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:cat requiringSecureCoding:YES error:&error];
// ***Error occurs here!!!***
NSLog(@"=== Error Info: %@ ===", [error localizedDescription]);
[data writeToFile:filePath atomically:YES];
}
+ (Cat *)getThisCat {
NSString *docPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
NSString *filePath = [docPath stringByAppendingPathComponent:@"cat.plist"];
Cat *retVal = [NSKeyedUnarchiver unarchivedObjectOfClass:[Cat class] fromData:[NSData dataWithContentsOfFile:filePath] error:nil];
return retVal;
}
@end
Usage:
Cat *totoro = [Cat new];
totoro.name = @"totoro";
totoro.age = 1;
NSLog(@"=== The cat's name is %@", totoro.name);
NSLog(@"=== The cat's age is %d", totoro.age);
[Cat saveThisCat:totoro];
Cat *resultCat = [Cat getThisCat];
NSLog(@"=== The cat's name is %@", resultCat.name);
NSLog(@"=== The cat's age is %d", resultCat.age);
And the error info (Generated by using archivedDataWithRootObject while executing saveThisCat method)
=== Error Info: The data couldn’t be written because it isn’t in the correct format. ===
Is there anything wrong? Please point it out, thanks a lot!
Upvotes: 3
Views: 3407
Reputation: 438487
When you call unarchivedObjectOfClass
, use the error
parameter and it will supply an NSError
:
Error Domain=NSCocoaErrorDomain Code=4864 "This decoder will only decode classes that adopt NSSecureCoding. Class 'Cat' does not adopt it." UserInfo={NSDebugDescription=This decoder will only decode classes that adopt NSSecureCoding. Class 'Cat' does not adopt it.}
As vadian said, adopt NSSecureCoding
.
Whenever you have a failure, always avail yourself of available NSError
parameters.
Upvotes: 4
Reputation: 285290
You have to adopt NSSecureCoding
@interface Cat : NSObject <NSSecureCoding>
and in the implementation add the required class property
+ (BOOL)supportsSecureCoding {
return YES;
}
Upvotes: 7