ios NSString文字列の一般的な方法

 

1.取得したウェブコードがGB 2312の場合、UTF-8形式コードに変換される.

NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);



NSString *retStr = [[NSString alloc] initWithData:data encoding:enc];

 
2.文字列が空か空白かを判断する

- (BOOL)isEmptyOrWhitespace {

  // A nil or NULL string is not the same as an empty string

  return 0 == self.length ||

         ![self stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]].length;

}

 
3.url文字列符号化

- (id)urlEncoded {

  CFStringRef cfUrlEncodedString = CFURLCreateStringByAddingPercentEscapes(NULL,

                                            (CFStringRef)self,NULL,

                                            (CFStringRef)@"!#$%&'()*+,/:;=?@[]",

                                            kCFStringEncodingUTF8);



  NSString *urlEncoded = [NSString stringWithString:(NSString *)cfUrlEncodedString];

  CFRelease(cfUrlEncodedString);

  return urlEncoded;

}

 4. NSStringからNSDataへの変換

- (NSData *)dataFormString:(NSString *)string

{

       if(!string) 

       {

             string = @"";

       }

       return [NSData dataWithBytes:[requestString UTF8String] length:strlen([requestString UTF8String])];

}