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  • ios -- NSdata 与 NSString,Byte数组,UIImage 的相互转换(转)

    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 ",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);
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  • 原文地址:https://www.cnblogs.com/JayK/p/4211167.html
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