objective c - How to convert nsdata to byte array

问题:

This question already has answers here:

How to convert NSData to byte array in iPhone? (6 answers)

Closed 7 years ago.

I am working with UIImage conversion to NSData. And I want to convert NsData to Byte Array and post that Byte array to server with the help of json Parser.

If i am passing following type of static string to server it accept and store. Following is just example string syntax. i want follwoing type of byte array to post data to server.

[255,216,255,224,0,16,74,70,73,70,0,1,1,1,0,96,0,96,0,0,255,219,0,67,0,8,6,6,7,6,5,8,7,7,7,9,9,8,10,12,...]

For above result i am converting image to data as following:

UIImage *image = [UIImage imageNamed:@"image.png"];
NSData *data = UIImagePNGRepresentation(image);

Now i want to convert NSdata to byte array for that i am using following code:

NSUInteger len = [data length];
Byte *byteData = (Byte*)malloc(len);
memcpy(byteData, [data bytes], len);
free(byteData)

and i also store this to NSdata. but cant get about result. I also typed about code with looping but every time it gives aPNG as result.

Am i doing any thing wrong in the above code?

Please provide me some help and also request to provide any help for this.

Thanks in advance.

回答1:

I'm not 100% sure this is what you are looking for or not. Try:

UIImage *image = [UIImage imageNamed:@"image.png"];
NSData *data = UIImagePNGRepresentation(image);
NSUInteger len = data.length;
uint8_t *bytes = (uint8_t *)[data bytes];
NSMutableString *result = [NSMutableString stringWithCapacity:len * 3];
[result appendString:@"["];
for (NSUInteger i = 0; i < len; i++) {
    if (i) {
        [result appendString:@","];
    }
    [result appendFormat:@"%d", bytes[i]];
}
[result appendString:@"]"];

Is this what you need?