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I Use Storage Access Framework to browse a file link f.cfg, when you select the file, the app need to load another file like f.dat automatically, how?

In Android Studio:
This app must use COMTRADE files. The COMTRADE files are *.cfg *.dat and *.rio files. For example, (user.cfg, user.dat and user.rio). The main file is *.cfg file, so the user must browse by SAF to find *.cfg files, when the user select this file, the app must load other files ( *.dat and *.rio) automatically.
I can not use <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/> for android level 30
So I have to use Storage Access Framework, By below code the user browse *.cfg files and select a file like user.cfg
if(SDK_INT >= Build.VERSION_CODES.R)
{
Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("*/*");
Act.startActivityForResult(intent, 111);
}
else
{...}
Then SAF return URI of that user.cfg file, and the app does not have any URI of other files to load.
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == 111)
{
if (resultCode == Activity.RESULT_OK)
{
if (data != null)
{
try
{
Uri uri = null;
uri = data.getData();
InputStreamReader inputStreamReader = new InputStreamReader(getContentResolver().openInputStream(uri));
BufferedReader br = new BufferedReader(inputStreamReader);
// I want URI of user.dat how?
InputStreamReader inputStreamReader1 = new InputStreamReader(getContentResolver().openInputStream(uri1));
BufferedReader br1 = new BufferedReader(inputStreamReader1);
....
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
}
}
}
Please help me how can I do this? Thanks.

Please help me how can I do this?
You cannot do this, at least by means of using ACTION_OPEN_DOCUMENT, unless you ask the user to open each of your three documents in turn. Just because the user selected a .cfg file does not mean that you have any rights to any other files, including those adjacent to it.
You could try using ACTION_OPEN_DOCUMENT_TREE and let the user choose the document tree that contains your desired files. From there, you can:
Use DocumentFile.fromTreeUri() to get a DocumentFile representing the tree
Call listFiles() on that DocumentFile to get the direct contents of that tree, in the form of a list of DocumentFile objects
Call getName() on each of those to get their display names, then see which names have your desired file extensions and matching base names (foo.cfg and foo.rio and foo.dat)
For those that you want to use, call getUri() on the DocumentFile to get a Uri to use with ContentResolver and openInputStream() to read in the content

Attaching files and uploading to server - Android Nougat

I am trying to upload files to server from my application. The user is allowed to attach the file from his internal storage. But some how the path I get from a Nougat phone is different from the standard /storage/emulated/0/... . in few phones I get external_files/... and in others I get root_files/storage/999/.... . In this case I am not getting the right path of the file. How do we handle this scenario?
My code :
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
Uri selectedImageUri = data.getData();
String filePath = data.getData().getPath();
File sourceFile = new File(fileFields.get(i).getFileName());
FileInputStream fileInputStream = new FileInputStream(sourceFile);
}
}

A Uri is not a file. getPath() is meaningless unless the scheme of the Uri happens to be file. That will not be very common on newer Android devices. Instead, the scheme will be content, and getPath() will be useless to you.
Instead, for both file and content Uri values, use a ContentResolver and openInputStream() to get an InputStream on the content identified by the Uri. This approach works all the way back to Android 1.0.

android filename from uri is not the same as actual filename

I need to get the name and extension of a file that I need to upload. I let the user select the file using an Intent call and get the URI as follows:
public void onActivityResult(int requestCode, int resultCode, Intent data) {
/* stuff */
Uri uri = data.getData();
String filePath = data.getData().getPath();
Log.d("filePath ",filePath);
Log.d("URI ", uri.toString());
String fileName = (new File(filePath)).getName();
Log.d("fileName ",fileName);
but the results are as follows:
com.blah.blah D/URI: content://com.android.providers.downloads.documents/document/354
com.blah.blah D/filePath: /document/354
com.blah.blah D/fileName: 354
the name of the file isn't even 354! its a PDF file (say "Bus e-Ticket.pdf" or "Xender.apk")
String fileName = (new File(filePath)).getAbsolutePath();
also yields the same.
how can i get the file name/exstension on disk?

but the results are as follows
getPath() is pointless on a Uri with a content scheme. getPath() is pointless on a Uri with any scheme other than file.
the name of the file isn't even 354
There is no requirement that there be a file. https://stackoverflow.com/questions/46060367/android-filename-from-uri-is-not-the-same-as-actual-filename is a Uri, and I feel fairly confident that there is no file on a Stack Overflow server at the path /questions/46060367/android-filename-from-uri-is-not-the-same-as-actual-filename.
how can i get the file name/exstension on disk?
There is no requirement that the user choose something that is a file. You can use DocumentFile.fromSingleUri() and getName() to get a "display name" for the content identified by the Uri. That does not have to be a filename with an extension.

You can use the MediaStore class to obtain the filename seen by the user. In specific use the MediaColumns interface as shown below
String[] projection = {MediaStore.MediaColumns.DISPLAY_NAME};
ContentResolver cr = mctx.getContentResolver();
Cursor metaCursor = cr.query(uri[0], projection, null, null, null);
if (metaCursor != null) {
try {
if (metaCursor.moveToFirst()) {
realFileName = metaCursor.getString(0);
}
} finally {
metaCursor.close();
}
}

Cannot create a file using the Uri of `ACTION_GET_CONTENT`

I'm trying to select pdf file from the device and upload them to the server. ACTION_GET_CONTENT is used to select pdf from the device.
sel_book.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent();
intent.setType("application/pdf");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select PDF"), 1);
}
});
On activity result I get the Uri and save it as a String.
public void onActivityResult(int requestCode, int resultCode, Intent result) {
if (resultCode == RESULT_OK) {
if (requestCode == 1) {
Uri uri = result.getData();
String uriString = uri.toString();
File myFile = new File(uriString);
path = myFile.getAbsolutePath();
}
}
}
It results the path as, /document/primary:Download/Aptitude_2016_17.pdf. I need to use this to create a new file. File selectedFile = new File(selectedFilePath);. But it doesn't create File. selectedFile.isFile() returns false. I have no idea why is it. Please help me to solve this. Thanks in advance.

ACTION_GET_CONTENT is used to select pdf from the device.
This allows the user to select a piece of content. It does not have to be a file.
On activity result I get the Uri and save it as a String.
That is not how you use a Uri.
It results the path as, /document/primary:Download/Aptitude_2016_17.pdf.
That is not a filesystem path. That is a part of a Uri that has a content scheme. You do not get a file from ACTION_GET_CONTENT. You get a Uri that points to a piece of content. That Uri could point to anything that the user and the other app choose:
A file that you can access, via a Uri with a file scheme
A file, but one that you cannot access (e.g., on internal storage of another app)
The contents of a BLOB column in the database
A piece of content that needs to be downloaded
And so on
Use ContentResovler and openInputStream() to get a stream on whatever the content is. Either use that directly (with whatever you are using to upload this content), or use that stream to make your own file with a copy of that content, so that you have a file that you can use.

SD-Card access API Android for Lollipop?

In this other question
How to use the new SD card access API presented for Android 5.0 (Lollipop)?
It is explained how to use the new API to access the "external SDCard".
But, how can I know the actual directory returned in the result activity?
I mean in function
public void onActivityResult(int requestCode, int resultCode, Intent resultData) {
if (resultCode == RESULT_OK) {
Uri treeUri = resultData.getData();
DocumentFile pickedDir = DocumentFile.fromTreeUri(this, treeUri);
......
How can I get the actual path where "Uri treeUri" points?
Thanks,
Francis.

You can't get the absolute path because the Documents API is designed to abstract this from you.
However, the treeUri does contain the relative path to the file. Try examining the Uri using Uri#getPathSegments()

Use
FileUtil.getFullPathFromTreeUri(treeUri, this)
from
https://github.com/jeisfeld/Augendiagnose/blob/f24ddd7d3da4df94552ca0a9e658399602855a67/AugendiagnoseIdea/augendiagnoseLib/src/main/java/de/jeisfeld/augendiagnoselib/util/imagefile/FileUtil.java
to get the full path. Seperate the path using
final String[] seperated = treeUri.toString().split("\\/");
to get the current dir name.