Android File文件存储功能

package com.lucky.test47file;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;

public class MainActivity extends AppCompatActivity {
    EditText editText1;
    TextView textView2;
    Button button1;
    Button button2;
    String fileName="lucky2.txt";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editText1=findViewById(R.id.editText);
        textView2=findViewById(R.id.textView2);
        button1=findViewById(R.id.button);
        button2=findViewById(R.id.button2);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    //采用打印流，输出数据，参数1为文件名称，参数2为数据的添加模式
                    FileOutputStream fileOutputStream=openFileOutput(fileName,MODE_APPEND);//实例化文件输出流
                    PrintStream printStream=new PrintStream(fileOutputStream); //实例化打印流
                    printStream.println(editText1.getText().toString()); //使用打印流输出数据
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                }
            }
        });
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    FileInputStream fileInputStream=openFileInput(fileName); //实例化文件输入流
                    BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(fileInputStream));
                    String tempString;
                    textView2.setText("文件的路径为："+MainActivity.this.getFilesDir());
                    while ((tempString=bufferedReader.readLine())!=null){  //逐行读取数据，直到结尾
                        textView2.append("\n"+tempString); //采用添加的方式保存文本
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

    }
}