iOS Development : writing byteArray ( Int8 ) to a file and retrieve the byteArray ( Int8 ) from the file

Converting Data and [Int8] is not so difficult.

Example data:

let data = Data([1,2,254,255])
print(data as NSData) //-> <0102feff>

Data to [Int8]:

var bytes: [Int8] = data.map{Int8(bitPattern: $0)}
print(bytes) //-> [1, 2, -2, -1]

[Int8] to Data:

let data2 = Data(bytes: bytes, count: bytes.count)
print(data2 as NSData) //-> <0102feff>

How to send data to your server depends on your server.

But, for example, you can use base64 encoding.

In Swift, Data can be easily coverted to base64 string:

let base64 = data.base64EncodedString()
print(base64) //-> AQL+/w==

If you decode the base64 string in Java, you can get byte array of type byte[].

Anyway, my recommendation, allways use `Data` on Swift side. You can send it in various ways -- raw binary, base64, hex...

And on Java side, you can easily receive it as or convert it to byte[].

Thank you so much. 🙂

Let me try this and will let you know.

Thank you so much for help.

I can now successfully create a file and read data back from it.

But i need to write in byteArray Int8[ ] instead of Data( ) format.

Is this possible ?

It would help if you explained the API you’re using to communicate with your server because the correct way to supply the data depends on the API. Some APIs, like

URLSession

Data

OutputStream

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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"