iOS - Performing Runtime Compatibility Checks

• Check platform geometry   

      if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)

• Check deployment platform  

      if ([[UIDevice currentDevice].model isEqualToString:@"iPad"]) 

•   Check system prefix       

       if ([[[UIDevice currentDevice] systemVersion] hasPrefix:@"5."])    

•  Check for properties using key-value coding    

       UILabel *label = (UILabel *)[cell valueForKey:@"textLabel"];

       if (label) [label setText:celltext]; 

•   Check for class existence    

               if (NSClassFromString(@"NSAttributedString")) . . .

•  Check for function existence       

       if(&UIGraphicsBeginImageContextWithOptions != NULL) . . .

•   Check for selector compliance    

        if ([cell respondsToSelector:@selector(selectorName:)])