How to get requestCode from Activity Result API - android-studio

Question

I am very new to Android Kotlin programming. I am making an app to create, read and delete file using Storage Access Framework. I did it by implementing deprecated startActivityForResult intent to perform file read, create, delete tasks. I tried to implement it using Activity Result API but I got stuck in request code which I could not find it.
In new implementation, there is resultCode but no requestCode.
My implemetation is below. How I can I implement the following using Activity Result API ?
How can I get request code from Activity Result API ?
fun createFile()
{
val filename: String = etFileName.text.toString()
val intent = Intent(Intent.ACTION_CREATE_DOCUMENT).apply {
type = "text/*"
addCategory(Intent.CATEGORY_OPENABLE)
putExtra(Intent.EXTRA_TITLE, filename)
}
startActivityForResult(intent, WRITE_REQUEST_CODE)
}
fun readFile(){
etFileName.setText("")
val intent = Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
addCategory(Intent.CATEGORY_OPENABLE)
type = "text/*"
}
startActivityForResult(intent, READ_REQUEST_CODE)
}
fun deleteFile(uri: Uri){
val filename = queryName(contentResolver, uri)
DocumentsContract.deleteDocument(contentResolver, uri)
Toast.makeText(applicationContext, "Done deleting $filename", Toast.LENGTH_SHORT).show()
}
fun writeText(uri: Uri) : String{
//var writetext: String = "typing high speed"
var writeStream = contentResolver.openFileDescriptor(uri, "w")
val filename: String = queryName(contentResolver, uri)
etFileName.setText(filename)
var fileOutputStream = FileOutputStream(writeStream?.fileDescriptor)
fileOutputStream.write(filename.toByteArray())
fileOutputStream.close()
return filename.toString()
}
fun openFileContent(uri: Uri): String{
val inputStream = contentResolver.openInputStream(uri)
val reader = BufferedReader(InputStreamReader(inputStream))
val stringBuilder = StringBuilder()
val filename = queryName(contentResolver, uri)
etFileName.setText(filename)
var currentline = reader.readLine()
while (currentline != null) {
stringBuilder.append(currentline + "\n")
currentline = reader.readLine()
}
inputStream?.close()
val str = stringBuilder.toString()
Log.d("Uri Read", ": $str")
return str
}
private fun queryName(resolver: ContentResolver, uri: Uri): String {
val returnCursor: Cursor = resolver.query(uri, null, null, null, null)!!
val nameIndex: Int = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
returnCursor.moveToFirst()
val name: String = returnCursor.getString(nameIndex)
returnCursor.close()
return name
}
override fun onActivityResult(requestCode: Int, resultCode: Int, resultData: Intent?) {
super.onActivityResult(requestCode, resultCode, resultData)
if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Read", "$uri")
if (uri != null) {
val readfile: String = openFileContent(uri)
etContent.setText(readfile)
}
} else if (requestCode == WRITE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
resultData?.data?.also { uri ->
Log.i("Uri Write", "Uri: $uri") // 1
val write = writeText(uri) // 2
etContent.setText(write)
}
} else if (requestCode == DELETE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Delete", "$uri")
if (uri != null) {
deleteFile(uri)
}
}
}
Since the above method is deprecated, I tried to implement it using Intent launcher, but there is no reference to requestCode anywhere so I am stuck here. It is as shown below :
val startforFile: ActivityResultLauncher<Intent> = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
result: ActivityResult ->
// could not find reference to requestCode here
if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Read", "$uri")
if (uri != null) {
val readfile: String = openFileContent(uri)
etContent.setText(readfile)
}
} else if (requestCode == WRITE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
resultData?.data?.also { uri ->
Log.i("Uri Write", "Uri: $uri") // 1
val write = writeText(uri) // 2
etContent.setText(write)
}
} else if (requestCode == DELETE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Delete", "$uri")
if (uri != null) {
deleteFile(uri)
}
}
}
Can anyone show me how it is done correctly ?

Answer 1

There are two ways with ActivityResultContracts.StartActivityForResult.
Make multiple requests by registering multiple listeners:
val startForFileRead: ActivityResultLauncher<Intent> = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
result: ActivityResult ->
if (resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Read", "$uri")
if (uri != null) {
val readfile: String = openFileContent(uri)
etContent.setText(readfile)
}
}
}
val startForFileWrite: ActivityResultLauncher<Intent> = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
result: ActivityResult ->
if (resultCode == Activity.RESULT_OK) {
resultData?.data?.also { uri ->
Log.i("Uri Write", "Uri: $uri") // 1
val write = writeText(uri) // 2
etContent.setText(write)
}
}
}
val startForFileDelete: ActivityResultLauncher<Intent> = registerForActivityResult(ActivityResultContracts.StartActivityForResult()){
result: ActivityResult ->
if (resultCode == Activity.RESULT_OK) {
val uri =resultData?.data
Log.d("Uri Delete", "$uri")
if (uri != null) {
deleteFile(uri)
}
}
}
Put an extra in your Intent returned from the other activity. Unpack it as your request code.
const val REQUEST_CODE = "REQUEST_CODE"
//...
val startForFile: ActivityResultLauncher<Intent> =
registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
val requestCode = result.data?.extras?.getInt(REQUEST_CODE)
if (requestCode == null) {
Log.e("FileResultLauncher", "No REQUEST_CODE was returned in data intent.")
return#registerForActivityResult
}
val uri = result.data?.data
if (uri == null || result.resultCode != RESULT_OK) {
Log.i("FileResultLauncher", "No Uri returned or result wasn't OK.")
return#registerForActivityResult
}
when (requestCode) {
READ_REQUEST_CODE -> {
Log.d("Uri Read", "$uri")
val readfile: String = openFileContent(uri)
etContent.setText(readfile)
}
WRITE_REQUEST_CODE -> {
Log.i("Uri Write", "Uri: $uri") // 1
val write = writeText(uri) // 2
etContent.setText(write)
}
DELETE_REQUEST_CODE -> {
Log.d("Uri Delete", "$uri")
deleteFile(uri)
}
}
}