当我通过 Print Writer 将数据存储到内部存储时，缓冲的 Reader 返回空数据

Question

亲爱的 StackOverflow 会员，祝您今天愉快。

实际上，我是 Android 的初学者，在下面的代码中，当我尝试通过缓冲读取器读取内部存储中存储的一些数据时，我遇到了以下问题。

当我尝试从“TestFile”文件中读取时，缓冲读取器返回空数据。

我花了很多时间试图解决这个问题，但仍未解决。

所以，请帮助我:(

package com.example.internalstorage;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class MainActivity extends AppCompatActivity {

    FileOutputStream fileOutputStream;
    PrintWriter printWriter;
    public static final String fileName = "TestFile";
    String allText = "";
    EditText editText;
    Button storeBtn;
    Button restoreBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText = findViewById(R.id.editText);
        storeBtn = findViewById(R.id.storeBtn);
        restoreBtn = findViewById(R.id.restoreBtn);



        try {
            File file = new File(getFilesDir(), fileName);
            if (file == null){

                try {
                    file.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }


            fileOutputStream = new FileOutputStream(fileName);

                  //  openFileOutput(fileName, MODE_PRIVATE);

            printWriter = new PrintWriter(fileOutputStream);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }


        storeBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                printWriter.println(editText.getText().toString());
                printWriter.println(editText.getText().toString());
                printWriter.println(editText.getText().toString());

                Toast.makeText(getBaseContext(), allText, Toast.LENGTH_SHORT).show();


            }
        });




        printWriter.close();
        try {
            fileOutputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }



        restoreBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                FileInputStream fileInputStream = null;
                InputStreamReader inputStreamReader = null;
                BufferedReader bufferedReader = null;


              //  getFilesDir().get

                try {
                    fileInputStream = openFileInput(fileName);
                    inputStreamReader = new InputStreamReader(fileInputStream);
                    bufferedReader = new BufferedReader(inputStreamReader);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }

                String line = "";
                try {

                    line = bufferedReader.readLine();

                    String s  = bufferedReader.readLine();
                    Toast.makeText(getBaseContext(), s +"321", Toast.LENGTH_SHORT).show();


                } catch (IOException e) {
                    e.printStackTrace();

                }




                while(line != null){

                    allText =  allText + line + "\n";
                    try {
                        line =  bufferedReader.readLine();

                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }


                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }


                try {
                    inputStreamReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }


                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }



                Toast.makeText(getBaseContext(), allText, Toast.LENGTH_SHORT).show();

//


            }
        });






    }
}

这是预期的 XML 文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="245dp"
        android:layout_height="73dp"
        android:layout_marginTop="356dp"
        android:layout_marginEnd="80dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:text="Name"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/storeBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="132dp"
        android:text="Store"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.479"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/restoreBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="36dp"
        android:text="restore"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.458"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>