将字节值放入NSDictionary [iOS] [英] Putting Byte value into NSDictionary [iOS]

问题描述

我有一个post web服务，我需要以字节数组发送图像，因为我需要以JSON格式发送post参数，所以我创建了它的 NSDictionary 。我的问题是如何在 Byte 的字典中为对象分配对象，我尝试这样做，并且在创建 NSDictionary 。我也用代码解释每个步骤，以便于理解下面的问题： -

I have a post web service, where I need to send image in byte array, and as I need to send post parameters in JSON format, I have created its NSDictionary. My issue is how can I assign object to key in dictionary for Byte, I tried doing so and application crashes while creating NSDictionary. I am also explaining each steps with code for easy understanding of y question below :-

这是我将图像转换为字节格式的代码： -

Here is my code for converting image to Byte format :-

NSData *data = [NSData dataWithContentsOfFile:filePath];
NSUInteger len = [data bytes];
Byte *byteData = (Byte*)malloc(len);
memcpy(byteData, [data bytes], len);

所以，现在我有字节其中包含现在我想将此对象分配给 NSDictionary 。这是代码，

So, now I have Byte which contain image in byte array, now I want to assign this object to NSDictionary. Here is code,

NSDictionary *dictJson = [NSDictionary dictionaryWithObjectsAndKeys:
byteData, @"photo",
nil];

现在我的应用程序在上面的行中崩溃，我在创建 dictJson object，有什么方法可以将Byte传递给 NSDictionary ？

Now my application crashes in above line where I am creating dictJson object, is there any way I can pass Byte to NSDictionary?

另外，另一个问题，我怎么能 NSLog byteData ？

Also, another question, how can I NSLog byteData?

请帮帮我。

提前致谢！

推荐答案

如果你真的想要将图像数据作为包含字节数字的JSON数组发送，
然后你必须手动创建数组，没有内置函数：

If you really want to sent the image data as a JSON array containing the bytes as numbers, then you have to create the array "manually", there is not built-in function:

NSData *data = ... // your image data
const unsigned char *bytes = [data bytes]; // no need to copy the data
NSUInteger length = [data length];
NSMutableArray *byteArray = [NSMutableArray array];
for (NSUInteger i = 0; i < length; i++) {
    [byteArray addObject:[NSNumber numberWithUnsignedChar:bytes[i]]];
}
NSDictionary *dictJson = [NSDictionary dictionaryWithObjectsAndKeys:
              byteArray, @"photo",
              nil];
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictJson options:0 error:NULL];

JSON数据看起来像

The JSON data would then look like

{"photo":[byte0, byte1, byte2, ...]}

所以也许这就是服务器所期望的。但请注意，这是一种非常无效的（就空间而言）发送图像数据的方式（例如，与Base64相比）。

So perhaps that is what the server expects. But note that this is a very ineffective (in terms of space) way to send image data (compared to Base64 for example).

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