Full source code to use a FileOutputStream to save the data in bytes. Then we use a FileInputStream and a BufferedReader to read them back into our app and rebuild our string using a StringBuilder
activity_main.xml
<?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="tech.codingpoint.internalstorageexample.MainActivity">
<EditText
android:id="@+id/edit_text"
android:layout_width="match_parent"
android:layout_height="200dp" />
<Button
android:id="@+id/button_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/edit_text"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:text="save"
android:onClick="save"/>
<Button
android:id="@+id/button_load"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignStart="@+id/button_save"
android:layout_below="@+id/button_save"
android:layout_marginTop="17dp"
android:text="load"
android:onClick="load"/>
</RelativeLayout>
MainActivity.java
package tech.codingpoint.internalstorageexample;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
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 static final String FILE_NAME = "example.txt";
EditText mEditText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mEditText = findViewById(R.id.edit_text);
}
public void save(View v) {
String text = mEditText.getText().toString();
FileOutputStream fos = null;
try {
fos = openFileOutput(FILE_NAME, MODE_PRIVATE);
fos.write(text.getBytes());
mEditText.getText().clear();
Toast.makeText(this, "Saved to " + getFilesDir() + "/" + FILE_NAME,
Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public void load(View v) {
FileInputStream fis = null;
try {
fis = openFileInput(FILE_NAME);
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String text;
while ((text = br.readLine()) != null) {
sb.append(text).append("\n");
}
mEditText.setText(sb.toString());
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}