NSData 与 NSString，Byte数组，UIImage 的相互转换

2015/01/21 32419

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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[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];  ///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);