Set MIME type when building BROWSE intents.

        final Intent intent = new Intent(DocumentsContract.ACTION_BROWSE);

        intent.addCategory(Intent.CATEGORY_DEFAULT);

        intent.setData(uri);

        intent.setDataAndType(uri, DocumentsContract.Root.MIME_TYPE_ITEM);

        // note that docsui treats this as *force* show advanced. So sending

        // false permits advanced to be shown based on user preferences.