在读取EncryptedFile时获取androidx.security.crypto.EncryptedFile（无此类文件或目录）

Question

我正在遵循有关数据加密的文档-https://developer.android.com/topic/security/data

读取En​​cryptedFile时出现错误，即-java.io.FileNotFoundException: androidx.security.crypto.EncryptedFile@742ce5e (No such file or directory)

这是我的代码-

public class ReadWriteChat {

    private KeyGenParameterSpec keyGenParameterSpec = MasterKeys.AES256_GCM_SPEC;
    private String masterKeyAlias;

    {
        try {
            masterKeyAlias = MasterKeys.getOrCreate(keyGenParameterSpec);
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private Context context;

    public ReadWriteChat(Context context){
        this.context = context;
    }

    public boolean write(){
        String fileToWrite = "my_sensitive_data.txt";
        try {
            EncryptedFile encryptedFile = new EncryptedFile.Builder(
                    new File(context.getFilesDir(), fileToWrite),
                    context,
                    masterKeyAlias,
                    EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
            ).build();

            // Write to a file.
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
                    encryptedFile.openFileOutput()));
            writer.write("MY SUPER-SECRET INFORMATION");
        } catch (GeneralSecurityException gse) {
            Log.d("GeneralSecurityExcepn 2",gse.toString());
            gse.printStackTrace();
            return false;
        } catch (IOException ex) {
            Log.d("IOException write",ex.toString());
            ex.printStackTrace();
            return false;
        }
        return true;
    }

    public String read(){

        String fileToRead = "my_sensitive_data.txt";
        EncryptedFile encryptedFile = null;
        StringBuffer stringBuffer = new StringBuffer();
        try {
            encryptedFile = new EncryptedFile.Builder(
                    new File(context.getFilesDir(), fileToRead),
                    context,
                    masterKeyAlias,
                    EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
            ).build();
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            Log.d("Read Write", e.toString());
            e.printStackTrace();
        }

        try (BufferedReader reader =
                     new BufferedReader(new FileReader(String.valueOf(encryptedFile)))) { //Getting error in this line.
            String line = reader.readLine();
            while (line != null) {
                stringBuffer.append(line).append('\n');
                line = reader.readLine();
            }
        } catch (IOException e) {
            Log.d("IOException read",e.toString()); //this line is printing the error.
            e.printStackTrace();
            return "";
        } finally {
            String contents = stringBuffer.toString();
            return contents;
        }
    }

}

我得到encryptedFile，但在尝试读取它时抛出错误。

请告诉我缺少了什么？