How to read and write a file in Android?

This source code shows you how to write a text into a file and also how to read it.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.zofiakreasi.readwrite">

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MainActivity.java

package com.zofiakreasi.readwrite;

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

public class MainActivity extends AppCompatActivity {

    String fileName = "myFile.txt";
    String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/ZofiaKreasi/";

    Button button1;
    Button button2;

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

        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                writeFile();
            }
        });

        button2 = (Button) findViewById(R.id.button2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                readFile();
            }
        });
    }

    public void writeFile(){
        try{
            new File(path).mkdir();
            File file = new File(path+fileName);
            if(!file.exists()){
                file.createNewFile();
            }
            FileOutputStream stream = new FileOutputStream(file,true);
            stream.write("Great job!".getBytes());
        }catch (FileNotFoundException ex){
            //
        }catch (IOException ex){
            //
        }
    }

    public void readFile(){
        String line = null;
        try{
            FileInputStream fileInputStream = new FileInputStream(new File(path+fileName));
            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream);
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            StringBuilder stringBuilder = new StringBuilder();
            while((line = bufferedReader.readLine()) != null){
                stringBuilder.append(line + System.getProperty("line.separator"));
            }
            fileInputStream.close();
            line = stringBuilder.toString();
            bufferedReader.close();
        }catch (FileNotFoundException ex){
            //
        }catch (IOException ex){
            //
        }
        Toast.makeText(this, line, Toast.LENGTH_LONG).show();
    }

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.zofiakreasi.readwrite.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Write"
        android:id="@+id/button1"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Read"
        android:id="@+id/button2"
        android:layout_below="@+id/button1"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

Original source of this codes is here: http://instinctcoder.com/read-and-write-text-file-in-android-studio/