Playing with SDcard

To develop a Android Application that writes data to the SD Card.

Students can perform IO operation and can manipulate data within SDcard.

Introduction

Student must familiar with the IO streams in java.io package and to work with.

Activities:

Activity 1:

Creating a New project:

• Open Android Studio and then click on File -> New -> New project.

• Then type the Application name as “no.9″ and click Next.

• Then select the Minimum SDK as shown below and click Next.

• Then select the Empty Activity and click

• It will take some time to build and load the project
• After completion it will look as given

Designing layout for the Android Application:

• Click on app -> res -> layout -> xml.

• Then delete the code which is there and type the code as given

Code for Activity_main.xml:

android:id=”@+id/editText” android:layout_width=”match_parent” android:layout_height=”wrap_content” android:singleLine=”true” android:textSize=”30dp” />

android:id=”@+id/button” android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_margin=”10dp” android:text=”Write Data” android:textSize=”30dp” />

android:id=”@+id/button2″ android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_margin=”10dp” android:text=”Read data” android:textSize=”30dp” />

android:id=”@+id/button3″ android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_margin=”10dp” android:text=”Clear” android:textSize=”30dp” />

• Now click on Design and your application will look as given

• So now the designing part is completed

Adding permissions in Manifest for the Android Application:

• Now include the WRITE_EXTERNAL_STORAGE permissions in the AndroidManifest.xml file as shown below

Code for AndroidManifest.xml:

android:allowBackup=”true” android:icon=”@mipmap/ic_launcher” android:label=”@string/app_name” android:supportsRtl=”true” android:theme=”@style/AppTheme” >

• So now the Permissions are added in the Manifest.

Java Coding for the Android Application:

• Click on app -> java -> example.exno9 -> MainActivity.

• Then delete the code which is there and type the code as given below

Code for MainActivity.java:

public class MainActivity extends AppCompatActivity

Button write,read,clear; @Override

protected void onCreate(Bundle savedInstanceState)

e1= (EditText) findViewById(R.id.editText); write= (Button) findViewById(R.id.button); read= (Button) findViewById(R.id.button2); clear= (Button) findViewById(R.id.button3);

public void onClick(View v)

String message=e1.getText().toString(); try

File f=new File(“/sdcard/myfile.txt”);

FileOutputStream fout=new FileOutputStream(f); fout.write(message.getBytes());

fout.close(); Toast.makeText(getBaseContext(),”Data Written in

catch (Exception e)

public void onClick(View v)

String message; String buf = “”; try

File f = new File(“/sdcard/myfile.txt”); FileInputStream fin = new FileInputStream(f); BufferedReader br = new BufferedReader(new

while ((message = br.readLine()) != null)

fin.close(); Toast.makeText(getBaseContext(),”Data Recived from

catch (Exception e)

Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_LONG).show();

public void onClick(View v)

• So now the Coding part is also completed
• Now run the application to see the output