Objective-C isMemberOfClass isKi

• 判断当前对象是否是cls类型

- (BOOL)isMemberOfClass:(Class)cls {
    return [self class] == cls;
}

• 判断当前对象是否是cls类，或者是否是cls的子类的类型

- (BOOL)isKindOfClass:(Class)cls {
    for (Class tcls = [self class]; tcls; tcls = tcls->superclass) {
        if (tcls == cls) return YES;
    }
    return NO;
}

• 判断当前类的元类对象是否是cls，如果要为YES，则cls必须传入元类对象

+ (BOOL)isMemberOfClass:(Class)cls {
    // object_getClass((id)self)为self的元类对象
    return object_getClass((id)self) == cls;
}

• 判断当前类的元类对象是否是cls或者是否是cls的子类，如果要为YES，则cls必须传入元类对象

+ (BOOL)isKindOfClass:(Class)cls {
    for (Class tcls = object_getClass((id)self); tcls; tcls = tcls->superclass) {
        if (tcls == cls) return YES;
    }
    return NO;
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // 等价于  [NSObjectisKindOfClass:[NSObject class]]);
        NSLog(@"%d", [[NSObject class] isKindOfClass:[NSObject class]]); // 1
        NSLog(@"%d", [[NSObject class] isMemberOfClass:[NSObject class]]); // 0
        NSLog(@"%d", [[MJPerson class] isKindOfClass:[MJPerson class]]); // 0
        NSLog(@"%d", [[MJPerson class] isMemberOfClass:[MJPerson class]]); // 0
        
        
        // 这句代码的方法调用者不管是哪个类（只要是NSObject体系下的），都返回YES, 为元类对象的superclass指向的是类对象
        NSLog(@"%d", [NSObject isKindOfClass:[NSObject class]]); // 1
        NSLog(@"%d", [NSObject isMemberOfClass:[NSObject class]]); // 0
        NSLog(@"%d", [MJPerson isKindOfClass:[MJPerson class]]); // 0
        NSLog(@"%d", [MJPerson isMemberOfClass:[MJPerson class]]); // 0
        
        
        id person = [[MJPerson alloc] init];
    
        NSLog(@"%d", [person isMemberOfClass:[MJPerson class]]); // 1
        NSLog(@"%d", [person isMemberOfClass:[NSObject class]]); // 0
        
        NSLog(@"%d", [person isKindOfClass:[MJPerson class]]); // 1
        NSLog(@"%d", [person isKindOfClass:[NSObject class]]); // 1
        
        
        NSLog(@"%d", [MJPerson isMemberOfClass:object_getClass([MJPerson class])]); // 1
        NSLog(@"%d", [MJPerson isKindOfClass:object_getClass([NSObject class])]); // 1
        
        NSLog(@"%d", [MJPerson isKindOfClass:[NSObject class]]);// 1
    }
    return 0;
}