Iphone开发－NSdata 与 NSString，Byte数组，UIImage 的相互转换
1. NSData 与 NSString
NSData－> NSString
NSString?*aString = [[NSString?alloc]?initWithData:adataencoding:NSUTF8StringEncoding];
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NSString－>NSData
NSString?*aString =?@"1234abcd";
NSData?*aData = [aString?dataUsingEncoding:?NSUTF8StringEncoding];
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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]);
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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];
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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);
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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
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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++;
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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
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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);
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3. NSData?与?UIImage
NSData－>UIImage
UIImage?*aimage = [UIImage?imageWithData: imageData];
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//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];
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UIImage－> NSData
NSData?*imageData =?UIImagePNGRepresentation(aimae);?
