选择PDF Android需要帮助！没有获得实际路径

Question

我正在尝试从Android SD卡中选择一个像这样的PDF

Intent intent = new Intent();

intent.setType("application/pdf");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Choose Documents"), DOCUMENT_SELECT_PDF);

此代码返回所选PDF文件的URI，如下所示

URI值

content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3D420

你们可以帮忙吗，我怎么能从这个URI中获得实际路径??????????

其余代码在这里

   case DOCUMENT_SELECT_PDF:
        if (resultCode == RESULT_OK) {
            try {
                final Uri pdfUri = imageReturnedIntent.getData();
                documentFilePath = DocumentHelper.getPDFPath(this, pdfUri);
                if (documentFilePath != null) {
                    documentName = DocumentHelper.getFileName(documentFilePath);
                    documentMimeType = DocumentHelper.getMimeType(this, pdfUri);
                    uploadDocuments();
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        break;