Dev question: how to prevent Adobe Reader from copying pdfs to "Download/Adobe Reader"?

Question

I am making an app that downloads pdf files from a server and the users can decide to store them in the phone. Those files are kept in the app's private storage.
The pdf files can be opened from inside the app. The problem is that every time a pdf is opened, adobe reader copies it in "Download/Adobe Reader" (the path may be different depending on the device and the android version). Those pdf files should not be available from outside my app. How can I prevent adobe reader from creating copies in that folder? Do I really have to make my app track them down and delete them? It wouldn't be the safest solution...
In order to open the files, I se up a content provider:
from the manifest:
<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="com.example.myapp.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true" >
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/filepaths" />
</provider>
And then, in a method, I do this:
File pdfToRead = new File(pdfPath);
Uri uri = FileProvider.getUriForFile(context, "com.example.myapp.fileprovider", pdfToRead);
for (ResolveInfo resolveInfo : appsList) {
    String packageName = resolveInfo.activityInfo.packageName;
    context.grantUriPermission(packageName, uri, Intent.FLAG_GRANT_READ_URI_PERMISSION);
openPDF(context, uri);
public static final void openPDF(Context context, Uri localUri) {
    Intent i = new Intent(Intent.ACTION_VIEW);
    i.setDataAndType(localUri, PDF_MIME_TYPE);
    context.startActivity(i);
Thanks for the help.

Answer 1

Meh, I just hoped there was a way to tell acrobat "don't create a copy of the file because it's private". For now, I'm detecting the "downloads/Adobe Reader" folder, look if there's the file that was opened and delete it.
Now I need to know something that I can't ask on stackoverflow: what paths does Adobe Reader use to create the "Adobe Reader" folder? Because not every device has an external sd card (external, not removable. Just for clarity). In my device it's at "Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)+"/Adobe Reader".