Android Internal Storage

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

1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
2.     xmlns:tools="http://schemas.android.com/tools"  
3.     android:layout_width="match_parent"  
4.     android:layout_height="match_parent"  
5.     tools:context=".MainActivity" >  
6.   
7.     <EditText  
8.         android:id="@+id/editText1"  
9.         android:layout_width="wrap_content"  
10.         android:layout_height="wrap_content"  
11.         android:layout_alignParentRight="true"  
12.         android:layout_alignParentTop="true"  
13.         android:layout_marginRight="20dp"  
14.         android:layout_marginTop="24dp"  
15.         android:ems="10" >  
16.   
17.         <requestFocus />  
18.     </EditText>  
19.   
20.     <EditText  
21.         android:id="@+id/editText2"  
22.         android:layout_width="wrap_content"  
23.         android:layout_height="wrap_content"  
24.         android:layout_alignRight="@+id/editText1"  
25.         android:layout_below="@+id/editText1"  
26.         android:layout_marginTop="24dp"  
27.         android:ems="10" />  
28.   
29.     <TextView  
30.         android:id="@+id/textView1"  
31.         android:layout_width="wrap_content"  
32.         android:layout_height="wrap_content"  
33.         android:layout_alignBaseline="@+id/editText1"  
34.         android:layout_alignBottom="@+id/editText1"  
35.         android:layout_alignParentLeft="true"  
36.         android:text="File Name:" />  
37.   
38.     <TextView  
39.         android:id="@+id/textView2"  
40.         android:layout_width="wrap_content"  
41.         android:layout_height="wrap_content"  
42.         android:layout_alignBaseline="@+id/editText2"  
43.         android:layout_alignBottom="@+id/editText2"  
44.         android:layout_alignParentLeft="true"  
45.         android:text="Data:" />  
46.   
47.     <Button  
48.         android:id="@+id/button1"  
49.         android:layout_width="wrap_content"  
50.         android:layout_height="wrap_content"  
51.         android:layout_alignLeft="@+id/editText2"  
52.         android:layout_below="@+id/editText2"  
53.         android:layout_marginLeft="70dp"  
54.         android:layout_marginTop="16dp"  
55.         android:text="save" />  
56.   
57.     <Button  
58.         android:id="@+id/button2"  
59.         android:layout_width="wrap_content"  
60.         android:layout_height="wrap_content"  
61.         android:layout_alignBaseline="@+id/button1"  
62.         android:layout_alignBottom="@+id/button1"  
63.         android:layout_toRightOf="@+id/button1"  
64.         android:text="read" />  
65.   
66. </RelativeLayout>  

Activity class

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

File: MainActivity.java

1. package example.now.com.internalstorage;  
2.   
3. import android.content.Context;  
4. import android.support.v7.app.AppCompatActivity;  
5. import android.os.Bundle;  
6. import android.view.View;  
7. import android.widget.Button;  
8. import android.widget.EditText;  
9. import android.widget.Toast;  
10.   
11. import java.io.BufferedReader;  
12. import java.io.FileNotFoundException;  
13. import java.io.FileOutputStream;  
14. import java.io.IOException;  
15. import java.io.InputStreamReader;  
16.   
17. public class MainActivity extends AppCompatActivity {  
18.     EditText editTextFileName,editTextData;  
19.     Button saveButton,readButton;  
20.     @Override  
21.     protected void onCreate(Bundle savedInstanceState) {  
22.         super.onCreate(savedInstanceState);  
23.         setContentView(R.layout.activity_main);  
24.   
25.         editTextFileName=findViewById(R.id.editText1);  
26.         editTextData=findViewById(R.id.editText2);  
27.         saveButton=findViewById(R.id.button1);  
28.         readButton=findViewById(R.id.button2);  
29.   
30.         //Performing Action on Read Button  
31.         saveButton.setOnClickListener(new View.OnClickListener(){  
32.   
33.             @Override  
34.             public void onClick(View arg0) {  
35.                 String filename=editTextFileName.getText().toString();  
36.                 String data=editTextData.getText().toString();  
37.   
38.                 FileOutputStream fos;  
39.                 try {  
40.                     fos = openFileOutput(filename, Context.MODE_PRIVATE);  
41.                     //default mode is PRIVATE, can be APPEND etc.  
42.                     fos.write(data.getBytes());  
43.                     fos.close();  
44.   
45.                     Toast.makeText(getApplicationContext(),filename + " saved",  
46.                             Toast.LENGTH_LONG).show();  
47.   
48.   
49.                 } catch (FileNotFoundException e) {e.printStackTrace();}  
50.                 catch (IOException e) {e.printStackTrace();}  
51.   
52.             }  
53.   
54.         });  
55.   
56.         //Performing Action on Read Button  
57.         readButton.setOnClickListener(new View.OnClickListener(){  
58.   
59.             @Override  
60.             public void onClick(View arg0) {  
61.                 String filename=editTextFileName.getText().toString();  
62.                 StringBuffer stringBuffer = new StringBuffer();  
63.                 try {  
64.                     //Attaching BufferedReader to the FileInputStream by the help of InputStreamReader  
65.                     BufferedReader inputReader = new BufferedReader(new InputStreamReader(  
66.                             openFileInput(filename)));  
67.                     String inputString;  
68.                     //Reading data line by line and storing it into the stringbuffer  
69.                     while ((inputString = inputReader.readLine()) != null) {  
70.                         stringBuffer.append(inputString + "\n");  
71.                     }  
72.   
73.                 } catch (IOException e) {  
74.                     e.printStackTrace();  
75.                 }  
76.                 //Displaying data on the toast  
77.             Toast.makeText(getApplicationContext(),stringBuffer.toString(),Toast.LENGTH_LONG).show();  
78.   
79.             }  
80.   
81.         });  
82.     }  
83. }