NSdata 与 NSString，Byte数组，UIImage 的相互转换---ios开发 Objective-C-优快云博客

转载自：http://www.cnblogs.com/jacktu/archive/2011/11/08/2241528.html

1. NSData 与 NSString
NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:adata encoding: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[i]);

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[i]&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];<wbr style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; padding-top:0px; padding-right:0px; padding-bottom:0px; padding-left:0px; color:rgb(65,65,65); font-family:simsun; text-align:left; background-color:rgb(247,250,242)">

///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);