字节数组到 NSData答案

【问题标题】：Byte Array to NSData字节数组到 NSData
【发布时间】：2012-08-08 08:43:23
【问题描述】：

WebService JSON 响应即将到来。在响应中，图像以字节数组的形式出现。我必须在 UIImageView 中显示图像。我正在尝试将字节数组转换为 NSData。但不知道如何做到这一点。任何帮助，将不胜感激。我确信字节数组中有图像数据。示例字节数组供您参考：

谢谢

【问题讨论】：

我建议不要添加您的问题中不需要的如此冗长的编码...
这不是 JSON。还是这些方括号而不是括号？
你在哪里有这个数组？是 C 风格的数组吗？
@BrunoFerreira 不，他将其作为 JSON 文本数组获取
@H2CO3 我认为这是NSLog() 输出。而NSLog() 打印NSArrays 与() 而不是[]。

标签： iphone ios objective-c bytearray nsdata

【解决方案1】：

这是将数据放入 NSData 对象的示例。

const unsigned char bytes[] = {values here};
NSData *data = [NSData dataWithBytes:bytes length:sizeof(bytes)];
NSLog(@"%@", data);

【讨论】：

这只回答了问题的最后一部分。

【解决方案2】：

您必须先将 JSON 转换为字符串数组；例如，您可以使用NSJSONSerialization class:

NSArray *strings = [NSJSONSerialization JSONObjectWithData:theJSONString options:kNilOptions error:NULL];

然后遍历字符串数组，将每个条目转换为整数，并将其添加到分配的字节指针/数组中：

unsigned c = strings.count;
uint8_t *bytes = malloc(sizeof(*bytes) * c);

unsigned i;
for (i = 0; i < c; i++)
{
    NSString *str = [strings objectAtIndex:i];
    int byte = [str intValue];
    bytes[i] = byte;
}

然后最终从字节中生成一个 NSData，然后使用它初始化一个 UIImage 对象：

NSData *imageData = [NSData dataWithBytesNoCopy:bytes length:c freeWhenDone:YES];
UIImage *image = [UIImage imageWithData:imageData];

【讨论】：

请注意，您从 JSON 中获取 NSNumber 对象而不是 NSStrings。但由于两者都响应 intValue 消息，您的代码仍然有效。最好写 NSNumber 甚至 id 。
什么是 JSONString？该方法需要 nsdata 而不是 nsstring.. 这是怎么回事？
如果没有收到 JSON 响应，如何获取 NSArray *strings？我得到 NSArray *strings nil.
将 freeWhenDone 设置为 YES 导致我的应用程序因 malloc: *** 错误而崩溃，但当我将其更改为 NO 时停止

【解决方案3】：

这里是如何在 Swift 中做到这一点...

var bytes:[Byte] = [137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 0, 130, 0, 0, 0, 22, 8, 6, 0, 0, 0, 12, 244, 68, 168, 0, 0, 0, 1, 115, 82, 71, 66, 0, 174, 206, 28, 233, 0, 0, 0, 4, 103, 65, 77, 65, 0, 0, 177, 143, 11, 252, 97, 5, 0, 0, 0, 9, 112, 72, 89, 115, 0, 0, 14, 196, 0, 0, 14, 196, 1, 149, 43, 14, 27, 0, 0, 3, 212, 73, 68, 65, 84, 104, 67, 237, 153, 61, 139, 20, 65, 16, 134, 55, 17, 253, 3, 114, 127, 224, 208, 204, 64, 228, 18, 3, 19, 21, 19, 35, 217, 200, 204, 15, 48, 19, 228, 48, 50, 242, 76, 12, 245, 2, 99, 47, 55, 88, 83, 65, 220, 76, 48, 57, 19, 49, 220, 95, 224, 125, 120, 34, 126, 224, 120, 207, 65, 141, 53, 189, 213, 85, 189, 238, 172, 176, 210, 5, 195, 206, 77, 87, 87, 247, 84, 189, 245, 118, 213, 220, 160, 169, 82, 61, 112, 232, 129, 65, 245, 66, 245, 0, 30, 168, 64, 168, 56, 56, 242, 64, 5, 66, 5, 66, 5, 66, 197, 192, 31, 15, 12, 142, 29, 63, 209, 228, 174, 209, 232, 101, 199, 87, 147, 201, 36, 171, 139, 141, 55, 227, 113, 179, 122, 234, 180, 171, 115, 110, 109, 173, 217, 217, 217, 53, 99, 112, 241, 210, 229, 169, 185, 216, 244, 246, 88, 50, 134, 93, 145, 18, 125, 79, 231, 230, 173, 219, 217, 253, 47, 51, 176, 92, 32, 156, 92, 89, 233, 188, 219, 189, 245, 245, 16, 8, 219, 219, 239, 27, 230, 69, 206, 76, 157, 246, 112, 99, 99, 106, 14, 78, 71, 230, 13, 94, 159, 64, 96, 47, 218, 222, 50, 7, 95, 239, 221, 5, 2, 47, 77, 96, 17, 178, 56, 10, 48, 217, 139, 192, 36, 81, 240, 158, 111, 109, 181, 251, 176, 178, 30, 102, 233, 43, 139, 75, 128, 192, 187, 161, 39, 87, 196, 108, 226, 23, 15, 8, 223, 70, 47, 154, 131, 7, 247, 155, 253, 27, 215, 155, 79, 103, 86, 59, 23, 207, 24, 67, 71, 203, 175, 253, 189, 230, 235, 179, 39, 157, 235, 199, 187, 183, 13, 23, 250, 123, 195, 171, 71, 118, 248, 229, 111, 158, 91, 130, 221, 207, 119, 239, 52, 59, 231, 207, 154, 107, 179, 6, 107, 137, 132, 64, 128, 202, 145, 167, 155, 155, 97, 112, 5, 8, 232, 91, 25, 174, 193, 129, 227, 113, 38, 0, 179, 156, 206, 49, 84, 2, 132, 89, 51, 50, 7, 208, 52, 203, 217, 151, 7, 102, 253, 174, 233, 30, 126, 126, 252, 208, 6, 44, 5, 128, 245, 55, 65, 101, 14, 66, 96, 83, 29, 43, 152, 90, 231, 251, 235, 87, 237, 22, 176, 19, 233, 235, 185, 2, 196, 16, 8, 165, 103, 191, 232, 105, 167, 64, 237, 158, 51, 1, 217, 181, 225, 112, 74, 7, 16, 105, 241, 108, 244, 5, 4, 246, 66, 112, 229, 138, 128, 239, 49, 130, 100, 109, 9, 8, 68, 103, 247, 202, 133, 44, 16, 34, 59, 4, 94, 196, 2, 1, 207, 96, 32, 139, 153, 176, 13, 248, 90, 32, 224, 136, 156, 195, 117, 198, 122, 122, 105, 150, 144, 85, 158, 190, 181, 158, 117, 254, 70, 199, 140, 55, 158, 218, 155, 199, 150, 204, 245, 106, 4, 178, 211, 10, 28, 52, 205, 24, 23, 247, 150, 14, 99, 22, 35, 136, 46, 129, 204, 101, 59, 64, 128, 238, 83, 187, 28, 31, 233, 209, 147, 234, 0, 220, 22, 8, 81, 6, 136, 19, 60, 61, 139, 46, 75, 106, 11, 177, 205, 113, 97, 117, 20, 243, 4, 175, 111, 32, 68, 93, 131, 21, 12, 28, 157, 138, 197, 26, 204, 205, 29, 13, 114, 116, 96, 199, 2, 3, 243, 172, 140, 103, 29, 97, 3, 126, 249, 219, 154, 223, 2, 129, 5, 162, 2, 73, 186, 136, 92, 96, 114, 231, 38, 52, 90, 18, 204, 180, 93, 45, 169, 17, 116, 129, 103, 221, 75, 231, 81, 98, 43, 98, 22, 93, 183, 228, 142, 36, 11, 8, 60, 75, 37, 167, 103, 1, 1, 6, 209, 98, 129, 136, 121, 127, 115, 36, 9, 59, 116, 128, 16, 177, 130, 156, 221, 179, 2, 129, 151, 136, 90, 79, 198, 115, 242, 47, 106, 4, 214, 240, 186, 34, 41, 110, 163, 154, 164, 132, 158, 177, 1, 101, 167, 20, 157, 99, 132, 20, 72, 86, 230, 151, 50, 130, 102, 7, 125, 223, 1, 66, 196, 10, 146, 17, 139, 0, 66, 238, 35, 19, 123, 138, 170, 119, 93, 228, 165, 247, 227, 195, 2, 80, 23, 118, 158, 173, 40, 17, 116, 75, 59, 11, 35, 16, 112, 221, 38, 114, 111, 213, 8, 60, 183, 24, 161, 20, 8, 95, 30, 63, 10, 107, 4, 169, 37, 210, 22, 117, 10, 8, 57, 103, 80, 221, 71, 244, 234, 181, 84, 81, 59, 233, 101, 90, 201, 177, 18, 209, 122, 180, 119, 230, 35, 81, 167, 83, 242, 49, 105, 150, 246, 77, 3, 130, 190, 126, 30, 32, 48, 223, 90, 155, 35, 3, 144, 88, 44, 196, 250, 204, 153, 2, 2, 206, 176, 40, 178, 36, 171, 254, 7, 32, 148, 116, 58, 105, 123, 155, 130, 56, 151, 241, 94, 27, 40, 140, 49, 15, 16, 216, 199, 172, 107, 3, 2, 10, 209, 129, 20, 88, 250, 101, 96, 5, 93, 120, 105, 54, 64, 79, 198, 104, 13, 245, 189, 215, 91, 243, 37, 49, 87, 216, 201, 71, 171, 28, 43, 48, 47, 93, 43, 183, 7, 235, 185, 174, 63, 188, 226, 82, 214, 231, 61, 162, 34, 52, 250, 178, 136, 115, 115, 25, 168, 1, 129, 142, 238, 8, 184, 151, 234, 94, 126, 211, 175, 143, 100, 183, 238, 6, 244, 7, 41, 222, 1, 102, 64, 199, 99, 38, 198, 244, 145, 83, 255, 13, 29, 85, 127, 61, 140, 19, 92, 249, 76, 44, 191, 58, 248, 61, 44, 225, 154, 72, 215, 182, 148, 43, 16, 22, 29, 133, 37, 177, 95, 129, 176, 36, 129, 90, 244, 54, 43, 16, 22, 237, 225, 37, 177, 255, 27, 38, 183, 224, 140, 178, 26, 189, 95, 0, 0, 0, 0, 73, 69, 78, 68, 174, 66, 96, 130];

var imageData:NSData = NSData(bytes: bytes, length: bytes.count);
var image:UIImage = UIImage(data: imageData);
var imageView:UIImageView = UIImageView(image: image);

【讨论】：

【解决方案4】：

我有办法在 Swift 中做到这一点

if let serverBytesArray = serverAnswer as? NSArray {
    var bytes:[Byte] = []
    for serverByte in serverBytesArray {
        bytes.append(Byte(serverByte as UInt))
    }
    var data = NSData(bytes: bytes, length: bytes.count);
    let tmpDir = NSTemporaryDirectory()
    data.writeToFile(tmpDir.stringByAppendingPathComponent("test.pdf"), atomically: true)
}

【讨论】：