Adding Multiple array into single Array in ios

You can use NSCache to cache items if you want, it works like an NSDictionary.

// Init NSCache and declare somewhere as property//you must use singleton approach as well, it's just example i have initialized in viewDidLoad

    - (void)viewDidLoad
    {    
       self.cache = [NSCache alloc] new];
    }

-(void)callApiForKey:(NSString *)buttonName{
        id aObject = [self.cache objectForKey:buttonName]
        if aObject == nil {
          //perform the API call you are talking about
          //after the fetch is preformed and you get data...
          [self.cache setObject: dataObject forKey:buttonName];
          //perform what you need to with said object
        } else {
          //perform operation with cached object
        }
    }

USES:

on your button click action call above method with buton text: yourButton.titleLabel.text.

[self callApiForKey:yourButton.titleLabel.text];

be suer keys must be unique. other wise you may get/set wrong data obviously.

Thanks

-Each button have a unique tag right? Like button 1 have tag 1, button 2 have tag 2 ,button 3 have tag 3,
-you can manage this thing by Global nsmutabledictionary and nsmutableArray.
-if you click on button 1 before api calling you check 
if(dictionary valueforkey:@"1") (1mean selected button tag)
{
  no need to call api 
  no need to add array in dictionary
  array=[[dictionary valueforkey:@"1"]mutablecopy];(1mean selected button tag)
  [tble reloaddata];

}
else
{
  api calling 
  here you can add array in dictionary
  [dictionary setobject:yourarray forkey:@"1"];
  array=[[dictionary valueforkey:@"1"]mutablecopy];(1mean selected button tag)
  [tble reloaddata];
}