Empty InputStream for file downloaded to MediaStore.Downloads

Question

I am trying to download a text file to MediaStore.Downloads (to support scoped storage in Android R) and then read the contents of that file.

I was initially using the DownloadManager to download the file to Environment.DIRECTORY_DOWNLOADS and then use a ContentResolver query to find the content:// Uri through MediaStore.Downloads. But I found the file was often not immediately available through the MediaStore (although it would appear at some point in the future).

So I moved on to using a JobIntentService to download the file using OkHttp to MediaStore.Downloads, e.g.

ContentResolver resolver = getApplicationContext().getContentResolver();
Uri downloads = MediaStore.Downloads.EXTERNAL_CONTENT_URI;
// Originally using MediaStore.Downloads.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY);

ContentValues fileContent = new ContentValues();
fileContent.put(MediaStore.Downloads.DISPLAY_NAME, file.name());
fileContent.put(MediaStore.Downloads.SIZE, fileSize);
fileContent.put(MediaStore.Downloads.IS_PENDING, 1);

Uri downloadedFileUri = resolver.insert(downloads, fileContent);  // Save this Uri for later access

try (InputStream inputStream = response.body().byteStream();
     OutputStream outputStream = resolver.openOutputStream(downloadedFileUri)) {
    // ... Download and write the file ...
}

fileContent.put(MediaStore.Downloads.IS_PENDING, 0);
resolver.update(downloadedFileUri, fileContent, null, null);

I then pass the saved Uri downloadedFileUri to another class that loads the file using an input stream, e.g.

try (InputStream inputStream = resolver.openInputStream(downloadedFileUri)) {
    Log.d(TAG, "Input stream size has " + inputStream.available() + " bytes available"); // This returns 0
    // ... read the file using a BufferedReader ...
}

But the InputStream contains no data. I've created a ContentResolver query to MediaStore.Downloads to confirm that the file is in the MediaStore:

try (Cursor cursor = resolver.query(MediaStore.Downloads.EXTERNAL_CONTENT_URI,
                        projection, null, null, idSortOrder)) {
    Log.i(TAG, DatabaseUtils.dumpCursorToString(cursor));  // I can see the file in the cursor dump here

    while (cursor.moveToNext()) {
        int id = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Downloads._ID));
        Uri uri = ContentUris.withAppendedId(MediaStore.Downloads.EXTERNAL_CONTENT_URI, id);
        if (downloadedFileUri.equals(uri)) {
            Log.d(TAG, "Uri from cursor matches params, Uri: " + uri); // Getting a match here
        }
    }
}

I can also find the downloaded file through the Files browser and confirm that the file is not empty. So why does the InputStream not return any data?

Empty InputStream for file downloaded to MediaStore.Downloads

0 Answers