Objective-c NSData转NSString后为nil 的解决办法

最新推荐文章于 2025-01-04 00:20:14 发布

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当NSData转为NSString时返回nil，可能是因为数据包含非UTF8字符。官方建议使用libiconv清除非UTF8字符，通过Link Binaries With Library将libiconv.dylib添加到项目中来解决此问题。

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Apple官方的文档:

Return Value

An NSString object initialized by converting the bytes in

data into Unicode characters using encoding. The returned object may be different from the original receiver. Returns nil

if the initialization fails for some reason (for example if data does not represent valid data for encoding).

Return Value

An NSString object initialized by converting the bytes in

data into Unicode characters using encoding. The returned object may be different from the original receiver. Returns nil

if the initialization fails for some reason (for example if data does not represent valid data for encoding).

返回nil很可能是编码问题, 有可能你的页面里混入了非utf8的字符

解决办法:

用libiconv清除非utf8字符

先给项目Link Binaries With Library 添加libiconv.dylib

#include "iconv.h"
 
- (NSData *)cleanUTF8:(NSData *)data {
  iconv_t cd = iconv_open("UTF-8", "UTF-8"); // 从utf8转utf8
  int one = 1;
  iconvctl(cd, ICONV_SET_DISCARD_ILSEQ, &one); // 丢弃不正确的字符
 
  size_t inbytesleft, outbytesleft;
  inbytesleft = outbytesleft = data.length;
  char *inbuf  = (char *)data.bytes;
  char *outbuf = malloc(sizeof(char) * data.length);
  char *outptr = outbuf;
  if (iconv(cd, &inbuf, &inbytesleft, &outptr, &outbytesleft)
      == (size_t)-1) {
    NSLog(@"this should not happen, seriously");
    return nil;
  }
  NSData *result = [NSData dataWithBytes:outbuf length:data.length - outbytesleft];
  iconv_close(cd);
  free(outbuf);
  return result;
}