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

Apple官方的文档:

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;
}