ios 判断当前设备

if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) 
   { 
       CGSize result = [[UIScreen mainScreen] bounds].size; 
        
       if(result.height == 480.f) 
       { 
           return @"ViewController"; 
       } 
       else 
       { 
           return @"ViewController-iPhone5"; 
       } 
   } 
 
   return @"ViewController-iPad";