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进制字符串
int j=0;
Byte bytes[128]; ///3ds
key的Byte 数组， 128位
for(int i=0;i<[hexString length];i++)
{
int int_ch; ///
两位16进制数转化后的10进制数
unichar hex_char1 =
[hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
int int_ch1;
if(hex_char1 >= ‘0‘ &&
hex_char1 <=‘9‘)
int_ch1 = (hex_char1-48)*16; ////
0 的Ascll
- 48
else if(hex_char1
>= ‘A‘ &&
hex_char1 <=‘F‘)
int_ch1 = (hex_char1-55)*16; ////
A 的Ascll
- 65
else
int_ch1 = (hex_char1-87)*16; ////
a 的Ascll
- 97
i++;
unichar hex_char2 =
[hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
int int_ch2;
if(hex_char2 >= ‘0‘ &&
hex_char2 <=‘9‘)
int_ch2 = (hex_char2-48); ////
0 的Ascll
- 48
else if(hex_char1
>= ‘A‘ &&
hex_char1 <=‘F‘)
int_ch2 = hex_char2-55; ////
A 的Ascll
- 65
else
int_ch2 = hex_char2-87; ////
a 的Ascll
- 97
int_ch = int_ch1+int_ch2;
NSLog(@"int_ch=%d",int_ch);
bytes[j] = int_ch; ///将转化后的数放入Byte数组里
j++;
}
NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];
NSLog(@"newData=%@",newData);
3. NSData 与 UIImage
NSData－>UIImage
UIImage *aimage = [UIImage imageWithData:
imageData];
//例：从本地文件沙盒中取图片并转换为NSData
NSString *path
= [[NSBundle mainBundle
bundlePath];
NSString *name
= [NSString stringWithFormat:@"ceshi.png"];
NSString *finalPath
=
[path stringByAppendingPathComponent:name];
NSData *imageData = [NSData dataWithContentsOfFile:
finalPath];
UIImage *aimage = [UIImage imageWithData:
imageData];
UIImage－> NSData
NSData *imageData
= UIImagePNGRepresentation(aimae);
http://w11h22j33.iteye.com/blog/1333521