How to list all pdf files on android 10?

Question

Since the changes related to the authorizations of access to the shared storage, it does not seem any more possible to search all the documents of the type pdf by this approach (with requestLegacyExternalStorage = "false"):

ContentResolver cr = context.getContentResolver();
Uri uri = MediaStore.Files.getContentUri("external");
String[] projection = null;
String selection = MediaStore.Files.FileColumns.MEDIA_TYPE + "="
                    + MediaStore.Files.FileColumns.MEDIA_TYPE_NONE;
String[] selectionArgs = null;
String sortOrder = null;
Cursor allNonMediaFiles = cr.query(uri, projection, selection, selectionArgs, sortOrder);

Check this link: Media data restrictions

The only solution I see is to scan in a recurcive way all the tree of the shared storage with SAF, which seems to me very expensive in resources and ridiculous.

Does anyone have another idea?

Answer 1

The basic idea of scoped storage is exactly to avoid this kind of behavior, you can't know if there are or not some files somewhere in the user phone. You can just ask for permission to access to the storage tree and scan everything as you said. Even in this case the user could select a folder different from the root so your app will be limited to that folder. The idea could be perform a scan and then update your database keeping in sync using a job (job service) scheduled on the modification of tree URI and descendants.

Answer 2

if your project targeted to Sdk level 29 you should add to your AndroidManifest.xml the flag android:requestLegacyExternalStorage="true" under your <application> tag.

 public List<String> queryFilesFromDevice(Uri uri, String[] projection, String selection, final Context context) {
    final List<String> tempList = new ArrayList<>();
    Cursor c = context.getContentResolver().query(uri, projection,
            selection,
            null,
            null);
    if (c != null) {

        while (c.moveToNext()) {
            String path = c.getString(0);
            long size = c.getLong(1);
         // your code logic should be here
        }
        c.close();
    }
    tempList.add(path);
    return tempList;
}

you need to call the function like this:

String pdfExt = "_data LIKE '%.pdf'";
Uri ducumentsUri = MediaStore.Files.getContentUri("external");
String[] docsProjection ={MediaStore.Files.FileColumns.DATA,MediaStore.Images.Media.SIZE,MediaStore.Files.FileColumns.MIME_TYPE,};
queryFilesFromDevice(ducumentsUri, docsProjection, pdfExt, this);