ACTION OPEN DOCUMENT TREE only returns empty Recent folder

Question

I have carefully copied the following code snippet from an earlier posting and it works, on the simulator and also on my Nexus 9 device, up to a point !

However, all I get is an empty Recent folder and I never reach the code that writes a file.

What must I change to get a proper document tree ?

   private void testDocumentTree() {

            Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
            startActivityForResult(intent, 42);
        }

        public void onActivityResult(int requestCode, int resultCode, Intent resultData) {
            String TAG = "onActivityResult";
            if (resultCode == RESULT_OK) {
                Uri treeUri = resultData.getData();
                DocumentFile pickedDir = DocumentFile.fromTreeUri(this, treeUri);

                // List all existing files inside picked directory
                for (DocumentFile file : pickedDir.listFiles()) {
                    Log.d(TAG, "Found file " + file.getName() + " with size " + file.length());
                }

                // Create a new file and write into it
                DocumentFile newFile = pickedDir.createFile("text/plain", "My Novel");
                try {
                    OutputStream out = getContentResolver().openOutputStream(newFile.getUri());
                    out.write("A long time ago...".getBytes());
                    out.close();
                } catch (FileNotFoundException e) {
                    Log.d(TAG, "File Not Found, reason: ", e);
                } catch (IOException e) {
                    Log.d(TAG,"IOException, reason: ", e);
                }
            }
        }

Answer 1

Others mentioned the option on DocumentsUI which the user should manually enable. However there is another option. Add these extras on to your ACTION_OPEN_DOCUMENT, ACTION_GET_CONTENT ,ACTION_CREATE_DOCUMENT or ACTION_OPEN_DOCUMENT_TREE intent. Explore button on Storage settings uses these extras while opening DocumentsUI app. I think the first one is enough to show Internal storage and sdcard. The others are good to have.

intent.putExtra("android.content.extra.SHOW_ADVANCED", true);
intent.putExtra("android.content.extra.FANCY", true);
intent.putExtra("android.content.extra.SHOW_FILESIZE", true);

---

Android 10

I tried on Android 10 emulator and OnePlus 7T, "SHOW_ADVANCED" extra does not do anything. User should manually click to "Show Internal storage" on the three dot menu. SDCards are visible by default.

Answer 2

I had the same problem as you do.

I clicked "Show internal storage" in the overflow menu

After that I was able to see "Internal storage" in the drawer