iOS difference between isKindOfClass and isMemberOfClass
IosObjective CSwiftClassInheritanceIos Problem Overview
What is the difference between the isKind(of aClass: AnyClass) and the isMember(of aClass: AnyClass) functions in Swift?
Original Question in Objective-C
>What is the difference between the isKindOfClass:(Class)aClass and the isMemberOfClass:(Class)aClass functions?
I know it is something small like, one is global while the other is an exact class match but I need someone to specify which is which please.
Ios Solutions
Solution 1 - Ios
isKindOfClass: returns YES if the receiver is an instance of the specified class or an instance of any class that inherits from the specified class.
isMemberOfClass: returns YES if, and only if, the receiver is an instance of the specified class.
Most of the time you want to use isKindOfClass: to ensure that your code also works with subclasses.
The NSObject Protocol Reference talks a little more about these methods.
Solution 2 - Ios
isKindOfClass:indicates whether an object inherits from a given classisMemberOfClass:indicates whether an object is an instance of a given class.
[[NSMutableData data] isKindOfClass:[NSData class]]; // YES
[[NSMutableData data] isMemberOfClass:[NSData class]]; // NO
Solution 3 - Ios
Suppose
@interface A : NSObject
@end
@interface B : A
@end
...
id b = [[B alloc] init];
then
[b isKindOfClass:[A class]] == YES;
[b isMemberOfClass:[A class]] == NO;
Basically, -isMemberOfClass: is true if the instance is exactly of the specified class, while -isKindOfClass: is true if the instance is exactly of the specified class or if one of the instance's ancestors is of the specified class.
-isMemberOfClass: is seldom used.
Solution 4 - Ios
> isKindOfClass: Returns a Boolean value that indicates whether the > receiver is an instance of given class or an instance of any class > that inherits from that class. > > isMemberOfClass: Returns a Boolean value that indicates whether the > receiver is an instance of a given class.
Solution 5 - Ios
isKindOfClass-> return YES when the object is instance of that class or instance of a class which is inherited from it.
isMemberOfClass: return YES when the object is instance of that class but No in case: instance of a class which is inherited from it.
example is good enough in jtbandes answer.
Solution 6 - Ios
Because of class clusters, isMemberOfClass can give you an answer you might not expect. In many cases your best choice is more likely to be -(BOOL)conformsToProtocol:(SEL)aSelector or - (BOOL)conformsToProtocol:(Protocol*)aProtocol. I.e, it's better to test these if they can answer your need rather than testing class/subclass.
See apple doc for NSObject class and protocol: