Android External Storage

There are several ways(Shared preferences, Internal storage, External storage, SQLite) to save data in android. Here we will discuss about Internal Storage.

Here is our final output:

Here you can download the source code: download

External storage is used to write and read data. User has a permission to access these files at anytime.

Primary External Storage: Inbuilt shared storage

Second External Storage: Removable storage (Ex: SD Card)

1. Open AndroidManifest.xml and below two permissions

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

2. Open activity_main.xml and paste below code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.externalstorage.MainActivity">


    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:fontFamily="monospace"
        android:hint="Write some data here..."
        android:paddingLeft="10dp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/file_path"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText"
        android:padding="10dp" />

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/file_path"
        android:gravity="center">

        <Button
            android:id="@+id/save"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="save" />

        <Button
            android:id="@+id/read"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/save"
            android:text="read" />

    </RelativeLayout>


</RelativeLayout>

3. Open MainActivity.java and paste below code

package com.externalstorage;

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.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.DataInputStream;
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 {

    private EditText data;
    private Button save, read;
    private TextView filePathTextView;

    private String fileName = "noteFile.txt";
    private String filePath = "myStore";
    private File noteFile;
    private StringBuilder dataBuilder = new StringBuilder();

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

        data = (EditText) findViewById(R.id.editText);

        save = (Button) findViewById(R.id.save);
        read = (Button) findViewById(R.id.read);

        filePathTextView = (TextView) findViewById(R.id.file_path);


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

                if (data.getText().toString().length()>0){
                    try {
                        FileOutputStream fileOutputStream = new FileOutputStream(noteFile);

                        fileOutputStream.write(data.getText().toString().getBytes());

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

                    filePathTextView.setText("");
                    filePathTextView.setText("noteFile.txt file saved to external storage");

                }
                else{
                    Toast.makeText(MainActivity.this,"Enter some data",Toast.LENGTH_SHORT).show();
                }


            }
        });

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

                try {
                    FileInputStream fileInputStream = new FileInputStream(noteFile);

                    //creating instance of DataInputStream
                    DataInputStream dataInputStream = new DataInputStream(fileInputStream);

                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(dataInputStream));
                    String line;

                    while ((line=bufferedReader.readLine())!=null){
                        dataBuilder.append(line);
                    }

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

                filePathTextView.setText("");
                filePathTextView.setText("noteFile.txt data recieved from external storage");

                data.setText(dataBuilder.toString());
            }
        });


        //checking whether external storage is avialble or not
        if (!isExternalStorageAvailable() || isExternalStorageReadOnly()) {
            //external storage is not available and is not writable, so we are making save button as not clickable

            save.setEnabled(false);
        } else {

            //if external storage is avilable and is writable
            noteFile = new File(getExternalFilesDir(filePath),fileName);
        }
    }

    private static boolean isExternalStorageAvailable() {

        /**
         * Returns the current state of the primary shared/external storage media.
         *
         * @see #getExternalStorageDirectory()
         * @return one of {@link #MEDIA_UNKNOWN}, {@link #MEDIA_REMOVED},
         *         {@link #MEDIA_UNMOUNTED}, {@link #MEDIA_CHECKING},
         *         {@link #MEDIA_NOFS}, {@link #MEDIA_MOUNTED},
         *         {@link #MEDIA_MOUNTED_READ_ONLY}, {@link #MEDIA_SHARED},
         *         {@link #MEDIA_BAD_REMOVAL}, or {@link #MEDIA_UNMOUNTABLE}.
         */
        String exeStoragestate = Environment.getExternalStorageState();

        if (exeStoragestate.equalsIgnoreCase(Environment.MEDIA_MOUNTED)) {
            return true;
        }
        return false;
    }

    private static boolean isExternalStorageReadOnly() {
        //if storage is only for read, then we can't do any write operations

        String exeStorageState = Environment.getExternalStorageState();

        if (exeStorageState.equalsIgnoreCase(Environment.MEDIA_MOUNTED_READ_ONLY)) {
            return true;
        }
        return false;
    }
}