I have the following method for my class which intends to load a nib file and instantiate the object:
- (id)initWithCoder:(NSCoder*)aDecoder
{
if(self = [super initWithCoder:aDecoder]) {
// Do something
}
return self;
}
How does one instantiate an object of this class?
What is this NSCoder? How can I create it?
MyClass *class = [[MyClass alloc] initWithCoder:aCoder];
You also need to define the following method as follows:
- (void)encodeWithCoder:(NSCoder *)enCoder {
[super encodeWithCoder:enCoder];
[enCoder encodeObject:instanceVariable forKey:INSTANCEVARIABLE_KEY];
// Similarly for the other instance variables.
....
}
And in the initWithCoder method initialize as follows:
- (id)initWithCoder:(NSCoder *)aDecoder {
if(self = [super initWithCoder:aDecoder]) {
self.instanceVariable = [aDecoder decodeObjectForKey:INSTANCEVARIABLE_KEY];
// similarly for other instance variables
....
}
return self;
}
You can initialize the object standard way i.e
CustomObject *customObject = [[CustomObject alloc] init];
The NSCoder class is used to archive/unarchive (marshal/unmarshal, serialize/deserialize) of objects.
This is a method to write objects on streams (like files, sockets) and being able to retrieve them later or in a different place.
I would suggest you to read http://developer.apple.com/library/mac/#documentation/cocoa/conceptual/Archiving/Archiving.html
