iOS: How to loop through objects / properties(Non UI elements) of a class object programmatically

Question

I am trying to NSLog, objects/properties of a viewController.

I have worked on looping through subviews,superviews (basically UIElements) like in below code

@interface ViewController : UIViewController 

{
NSString *string;
NSMutableArray *mutableArray ;
NSMutableDictionary *mutableDictionary;    
}
@property NSString *string;
@property NSMutableArray *mutableArray ;
@property NSMutableDictionary *mutableDictionary; 


@implementation ViewController

-(void) loopThrough{
  for (id obj in [self.view subviews]) {
    nslog(@"This would print subviews properties%@", obj)
}

}

My question is similar to the above is it possible to loop through set of Non UI elements per se NSString, NSArray and etc.,

Implementation Scenario
I have 4 network call timeout timers in viewController and when even one is succeeded with network calls, timeout timer has to be disabled. But since there are four network calls happening, I don't want to declare 4 timer global variables of viewController and invalidate each timer separately. Rather I would like to loop through and invalidate timers.

Answer 1

You need to use Objective C run-time libraries for this

#import <objc/runtime.h>

- (NSSet *)propertyNames {
   NSMutableSet *propNames = [NSMutableSet set];
   unsigned int outCount, i;
   objc_property_t *properties = class_copyPropertyList([self class], &outCount);
   for (i = 0; i < outCount; i++) {
       objc_property_t property = properties[i];
       NSString *propertyName = [NSString stringWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
       [propNames addObject:propertyName];
   }
   free(properties);
   return propNames;
}

- (void)loopThrough {
  for(NSString *key in [self propertyNames]) {
       NSLog (@"value = %@ , property %@",[self valueForKey:key],key);
  }
}