如何从使用getStreamPath

Question

我正在开发一种图书阅读器应用程序，用户可以在epub format上阅读其图书。

成功下载后，我正在使用folioReader库来存放书籍。

这是我下载每本书的方式（效果很好）

private void downloadFile(final String fileName){
        @SuppressLint("StaticFieldLeak") AsyncTask<Void, Integer, Boolean> asyncTask = new AsyncTask<Void, Integer, Boolean>() {
            @Override
            protected Boolean doInBackground(Void... params) {
                return downloadFile();
            }
            @NonNull
            private Boolean downloadFile(){
                try {
                    file = getFileStreamPath(fileName);
                    if (file.exists()) {
                        button_text.setText("READ");
                        return true;
                    }
                    try {
                        FileOutputStream fileOutputStream = openFileOutput(fileName, Context.MODE_PRIVATE);
                        URL url = new URL(document);
                        URLConnection urlConnection = url.openConnection();
                        int contentLength = urlConnection.getContentLength();
                        InputStream inputStream = new BufferedInputStream(url.openStream());
                        byte[] data = new byte[contentLength];
                        long total = 0;
                        int count;
                        while ((count = inputStream.read(data)) != -1) {
                            total += count;
                            publishProgress((int) ((total * 100) / contentLength));
                            fileOutputStream.write(data, 0, count);

                        }
                        fileOutputStream.flush();
                        fileOutputStream.close();
                        inputStream.close();
                        return true;
                    } catch (final Exception e) {
                        e.printStackTrace();
                        return false; //swallow a 404
                    }
                }catch (Exception e){
                    e.printStackTrace();
                    Toast.makeText(BookDetailsActivity.this, e.toString(), Toast.LENGTH_SHORT).show();
                }
                return false;

            }

            @Override
            protected void onProgressUpdate(Integer... values) {
                super.onProgressUpdate(values);
                seekBar.setProgress(values[0]);
            }

            @Override
            protected void onPostExecute(Boolean aBoolean) {
                super.onPostExecute(aBoolean);
                if(aBoolean){
                    button_text.setText("READ");
                } else {
                    button_text.setText("DOWNLOAD");

                }
                downloadProgress.setVisibility(View.GONE);
            }
        };
        asyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    }

但是，我无法成功读取/检索保存到内部存储器中的文档的位置。我的错误不断告诉我该路径无效。这是我阅读文档的代码。（不起作用）

 try{
            File file = getFileStreamPath(title);
            folioReader.openBook(file.toString());
            Log.e("file: ", file.toString());
        } catch (Exception e){
            e.printStackTrace();
        }
    }