Android USB OTG storage

Question

I want to export my app data on USB storage. As I read before in many threads it is not possible to write secondary storage (primary is always device).

I'm considering that if it's possible to connect any devices like pad or else and write custom communication with it (in host mode) – https://developer.android.com/guide/topics/connectivity/usb, so maybe it is possible to write custom communication with usb storage.

Anyone try something like that? Is it possible?

Edit

Now I can add single file -- here is my solution:

class MainActivity : AppCompatActivity() {

    lateinit var resultLauncher: ActivityResultLauncher<Intent>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        findViewById<View>(R.id.button).setOnClickListener { createFile() }

        resultLauncher = registerForActivityResult(
            ActivityResultContracts.StartActivityForResult()
        ) { result ->
            if (result.resultCode == Activity.RESULT_OK) {
                writeInFile(result.data!!.data!!, "Hello world")
            }
        }
    }

    private fun createFile() {
        val intent = Intent(Intent.ACTION_CREATE_DOCUMENT)
        intent.addCategory(Intent.CATEGORY_OPENABLE)
        intent.type = "text/plain"
        intent.putExtra(Intent.EXTRA_TITLE, "Neonankiti.txt")
        resultLauncher.launch(intent)
    }

    private fun writeInFile(uri: Uri, text: String) {
        val outputStream: OutputStream?
        try {
            outputStream = contentResolver.openOutputStream(uri)
            val bw = BufferedWriter(OutputStreamWriter(outputStream))
            bw.write(text)
            bw.flush()
            bw.close()
        } catch (e: IOException) {
            e.printStackTrace()
        }
    }

}

Now I want to know how to add multiple files in directory.

You dont need anything custom. Just use Storage Access Framework. For instance ACTION_CREATE_DOCUMENT. — blackapps, Aug 28 '21 at 06:05
Thank you, now I prepare choose directory. Now I will prepare adding file, thank you — M. Liver, Aug 28 '21 at 08:40
@blackapps is it possible to save directory? I want to save many files. — M. Liver, Aug 29 '21 at 06:24
Yes, all is possible. Whatever that would be: save directory. — blackapps, Aug 29 '21 at 06:30
That looks like bad coding. But how could we know? No idea what you do. — blackapps, Aug 29 '21 at 07:49
I put my single file solution in answer below. Please describe mi how to change it to multiple files — M. Liver, Aug 29 '21 at 13:27

Android USB OTG storage

0 Answers0