What is the Objective-C equivalent for "toString()", for use with NSLog?
It is the description
instance method, declared as:
- (NSString *)description
Here's an example implementation (thanks to grahamparks):
- (NSString *)description {
return [NSString stringWithFormat: @"Photo: Name=%@ Author=%@", name, author];
}
There are two functions that you can use.
- (NSString*)description
This will be displayed when you put your object as, I.E. a parameter for NSLog
. The other description function is:
- (NSString*)debugDescription
This will be called when you do po anInstanceOfYourClass
in the debug command window. If your class doesn't have a debugDescription
function, then just description
will be called.
Note that the base class NSObject
does have description
implemented, but it is fairly bare-bones: it only displays the address of the object. This is why I recommend that you implement description
in any class you want to get info out of, especially if you use the description
method in your code. If you do use description
in your code, I suggest you implement debugDescription
as well, also making debugDescription
more verbose.
You can override the description method of NSObject:
- (NSString *)description
On the subject of logging I recommend this blog post for better logging in Objective-C.
Add this to the @implementation
of your Photo class:
- (NSString *)description {
return [NSString stringWithFormat:@"Photo: Name=%@ Author=%@",name,author];
}