Internal Storage Example in Android

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="enter file name:"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/editText_filename"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName" >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="enter text to save"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/editText_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName" />

    <Button
        android:id="@+id/button_save"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:text="Create file and save text" />

    <Button
        android:id="@+id/button_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:text="view text from saved file" />

    <TextView
        android:id="@+id/textView_display"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

MainActivity.java

package in.blogspot.kantapp.internalstorageexampleinandroid;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends Activity {
    private EditText editFile, editText;
    private TextView text;

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

        editFile = (EditText) findViewById(R.id.editText_filename);
        editText = (EditText) findViewById(R.id.editText_text);
        text = (TextView) findViewById(R.id.textView_display);

        Button saveBtn = (Button) findViewById(R.id.button_save);
        Button viewBtn = (Button) findViewById(R.id.button_view);

        saveBtn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                String fileName = editFile.getText().toString();
                String textToSave = editText.getText().toString();

                try {
                    FileOutputStream fos = openFileOutput(fileName + ".txt",
                            MODE_PRIVATE);

                    fos.write(textToSave.getBytes());

                    fos.close();

                    Toast.makeText(getApplicationContext(),
                            "file created and text saved", Toast.LENGTH_LONG)
                            .show();
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });

        viewBtn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                try {
                    FileInputStream fis = openFileInput(editFile.getText()
                            .toString() + ".txt");

                    StringBuffer sb = new StringBuffer();

                    int i;

                    while ((i = fis.read()) != -1) {

                        sb.append((char) i);
                    }

                    fis.close();

                    text.setText(sb.toString());
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        });
    }
}