How to initialize this archived object?
I have made an class that conforms to the protocol. So I have implemented an init method like this:
- (id)initWithCoder:(NSCoder*)decoder {
if ((self = [super init])) {
self.someIvarObject = [decoder decodeObjectForKey:kObjectKey];
}
return self;
}
Of course I also have an -(void)encodeWithCoder:(NSCoder*)encoder
method implem开发者_运维百科ented.
I haven't figured out yet how I would archive this object now. Would I have to create an instance of my object and then just call -initWithCoder: and supply an appropriate NSCoder object?
The reason I ask is that I need to know if it's possible to add another parameter to this initialization method. When I call it by myself that should be no problem I guess. Although I would have to implement the -(void)encodeWithCoder:(NSCoder*)encoder
with the correct signature for the protocol.
Maybe someone can supply a little example that quickly shows how an object is unarchived?? that would be great!
EDIT: Here's a more detailed example of what I try to do. Don't know yet if this will work with an archivable object like this...
- (id)initWithCoder:(NSCoder*)decoder somethingSpecial:(Special*)special {
if ((self = [super init])) {
self.someIvarObject = [decoder decodeObjectForKey:kObjectKey];
self.somethingSpecial = special;
}
return self;
}
- (id)initWithCoder:(NSCoder*)decoder {
return [self initWithCoder:decoder decimalCalculator:nil];
}
To encode your object, call:
NSData *archive = [NSKeyedArchiver archivedDataWithRootObject:myObject];
To decode it:
MyObject *myObject = [NSKeyedUnarchiver unarchiveObjectWithData:archive];
You can take a look at the NSArchiver
class.
It's a subclass of NSCoder
that will archive and unarchive from/to an NSData
object.
You can then store the NSData
on a file, or any other place to recreate the objects.
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