Internal Memory in Android

Mainactivity.Java

package com.example.internalmemory;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

EditText textmsg;
static final int READ_BLOCK_SIZE = 100;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

textmsg=(EditText)findViewById(R.id.editText1);
}

// write text to file
public void WriteBtn(View v) {
// add-write text into file
try {
FileOutputStream fileout=openFileOutput("mytextfile.txt", MODE_PRIVATE);
OutputStreamWriter outputWriter=new OutputStreamWriter(fileout);
outputWriter.write(textmsg.getText().toString());
outputWriter.close();

//display file saved message
Toast.makeText(getBaseContext(), "File saved successfully!",
Toast.LENGTH_SHORT).show();

} catch (Exception e) {
e.printStackTrace();
}
}

// Read text from file
public void ReadBtn(View v) {
//reading text from file
try {
FileInputStream fileIn=openFileInput("mytextfile.txt");
InputStreamReader InputRead= new InputStreamReader(fileIn);

char[] inputBuffer= new char[READ_BLOCK_SIZE];
String s="";
int charRead;

while ((charRead=InputRead.read(inputBuffer))>0) {
// char to string conversion
String readstring=String.copyValueOf(inputBuffer,0,charRead);
s +=readstring;
}
InputRead.close();
Toast.makeText(getBaseContext(), s,Toast.LENGTH_SHORT).show();

} catch (Exception e) {
e.printStackTrace();
}
}
}

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="{relativePackage}.${activityClass}" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:background="#008080"
        android:padding="5dp"
        android:text="Android Read and Write Text form File"
        android:textColor="#fff" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="22dp"
        android:ems="10"
        android:layout_margin="5dp">
        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/editText1"
        android:text="Write Text into File"
        android:onClick="WriteBtn"
        android:layout_margin="5dp"/>
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/button1"
        android:text="Read Text From file"
        android:onClick="ReadBtn"
        android:layout_margin="5dp" />
</RelativeLayout>

Output: