ios NSString 去除首尾和中間空格

//    NSString* trimedURL = [stringURL stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

    

    NSString *theString =
@"    Hello      this  is a   long       string!   ";  

    

    NSCharacterSet *whitespaces = [NSCharacterSet
whitespaceCharacterSet];  

    NSPredicate *noEmptyStrings = [NSPredicate
predicateWithFormat:@"SELF != ''"];  

    

    NSArray *parts = [theString
componentsSeparatedByCharactersInSet:whitespaces];  

    NSArray *filteredArray = [parts
filteredArrayUsingPredicate:noEmptyStrings];  

    theString = [filteredArray componentsJoinedByString:@""];