Iphone开发－NSdata 与 NSString，Byte数组，UIImage 的相互转换

 原文摘自：NSdata转化为int

1. NSData 与 NSString
NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:adataencoding:NSUTF8StringEncoding];

NSString－>NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

2.NSData 与 Byte
NSData－> Byte数组
NSString *testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
for(int i=0;i<[testData length];i++)
printf("testByte = %d\n",testByte);

Byte数组－> NSData
Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

Byte数组－>16进制数
Byte *bytes = (Byte *)[aData bytes];
NSString *hexStr=@"";
for(int i=0;i<[encryData length];i++)
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes&0xff];///16进制数
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else 
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
NSLog(@"bytes 的16进制数为:%@",hexStr);

16进制数－>Byte数组
///// 将16进制数据转化成Byte 数组
NSString *hexString = @"3e435fab9c34891f"; //16进制UIImagePNGRepresentation(aimae);