Internal Storage Android

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To read or write data from a device’s internal memory with the help of the FileInputStream and FileOutputStream classes, Android Internal Storage is used.

Example: To read and write data to the android internal storage:

activity_main.xml:

In the activity_main.xml file, we will drag the EditTexts, TextViews, and buttons from the palette.

<?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"
    tools:context=".MainActivity" >
 
    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="20dp"
        android:layout_marginTop="24dp"
        android:ems="10" >
 
        <requestFocus />
    </EditText>
 
    <EditText
        android:id="@+id/editText2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/editText1"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="24dp"
        android:ems="10" />
 
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/editText1"
        android:layout_alignBottom="@+id/editText1"
        android:layout_alignParentLeft="true"
        android:text="File:" />
 
    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/editText2"
        android:layout_alignBottom="@+id/editText2"
        android:layout_alignParentLeft="true"
        android:text="Information to Feed:" />
 
    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText2"
        android:layout_below="@+id/editText2"
        android:layout_marginLeft="70dp"
        android:layout_marginTop="16dp"
        android:text="save" />
 
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_toRightOf="@+id/button1"
        android:text="read" />
 
</RelativeLayout>

Activity class:(File: MainActivity.java)

In the MainActivity.java file, we will write the code to save and to read data from the internal storage.

package com.example.radioapp;
 
import android.content.Context;
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.Toast;
 
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class MainActivity extends AppCompatActivity {
    EditText editTextFileName,editTextData;
    Button saveButton,readButton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        editTextFileName=findViewById(R.id.editText1);
        editTextData=findViewById(R.id.editText2);
        saveButton=findViewById(R.id.button1);
        readButton=findViewById(R.id.button2);
 
        //Performing Action on Read Button
        saveButton.setOnClickListener(new View.OnClickListener(){
 
            @Override
            public void onClick(View arg0) {
                String filename=editTextFileName.getText().toString();
                String data=editTextData.getText().toString();
 
                FileOutputStream fos;
                try {
                    fos = openFileOutput(filename, Context.MODE_PRIVATE);
                    //default mode is PRIVATE, can be APPEND etc.
                    fos.write(data.getBytes());
                    fos.close();
 
                    Toast.makeText(getApplicationContext(),filename + " stored",
                            Toast.LENGTH_LONG).show();
 
 
                } catch (FileNotFoundException e) {e.printStackTrace();}
                catch (IOException e) {e.printStackTrace();}
 
            }
 
        });
 
        //Performing Action on Read Button
        readButton.setOnClickListener(new View.OnClickListener(){
 
            @Override
            public void onClick(View arg0) {
                String filename=editTextFileName.getText().toString();
                StringBuffer stringBuffer = new StringBuffer();
                try {
                    //Attaching BufferedReader to the FileInputStream by the help of InputStreamReader
                    BufferedReader inputReader = new BufferedReader(new InputStreamReader(
                            openFileInput(filename)));
                    String inputString;
                    //Reading data line by line and storing it into the stringbuffer
                    while ((inputString = inputReader.readLine()) != null) {
                        stringBuffer.append(inputString + "\n");
                    }
 
                } catch (IOException e) {
                    e.printStackTrace();
                }
                //Displaying data on the toast
                Toast.makeText(getApplicationContext(),stringBuffer.toString(),Toast.LENGTH_LONG).show();
 
            }
 
        });
    }
}

Output 1:

Output 2:

Output 3:

Output 4: