Android Internal Storage Example

We are able to save or read data from the device internal memory. FileInputStream and FileOutputStream classes are used to read and write data into the file.

Here, we are going to read and write data to the internal storage of the device.

Example of reading and writing data to the android internal storage

activity_main.xml

Drag the 2 edittexts, 2 textviews and 2 buttons from the pallete, now the activity_main.xml file will like this:

File: activity_main.xml

<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 Name:" />

    <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="Data:" />

    <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

Let's write the code to write and read data from the internal storage.

File: MainActivity.java

package com.example.internalstorage;

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 android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
	EditText editTextFileName,editTextData;
	Button saveButton,readButton;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		editTextFileName=(EditText)findViewById(R.id.editText1);
		editTextData=(EditText)findViewById(R.id.editText2);
		saveButton=(Button)findViewById(R.id.button1);
		readButton=(Button)findViewById(R.id.button2);
		
		//Performing Action on Read Button
		saveButton.setOnClickListener(new 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 + " saved",
							Toast.LENGTH_LONG).show();
				    
				   
				   } catch (FileNotFoundException e) {e.printStackTrace();}
				   catch (IOException e) {e.printStackTrace();}
				
			}
			
		});
		
		//Performing Action on Read Button
		readButton.setOnClickListener(new 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();
			    
			}
			
		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.activity_main, menu);
		return true;
	}

}

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