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:

Procedure:

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

 

• Finally click Finish.

• 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.

• Now click on Text as shown

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

Code for Activity_main.xml:

<?xml version=”1.0″ encoding=”utf-8″?>

<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” android:layout_width=”match_parent” android:layout_height=”match_parent”

android:layout_margin=”20dp” android:orientation=”vertical”>

<EditText

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

<Button

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” />

<Button

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” />

<Button

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

</LinearLayout>

• 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:

• Click on app -> manifests -> xml

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

<?xml version=”1.0″ encoding=”utf-8″?>

Code for AndroidManifest.xml:

<manifest package=”com.example.exno9″ >

<uses-permission android:name=”android.permission.WRITE_EXTERNAL_STORAGE”></uses-permission>

<application

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

<activity android:name=”.MainActivity” >

<intent-filter>

<action android:name=”android.intent.action.MAIN” />

<category android:name=”android.intent.category.LAUNCHER” />

</intent-filter>

</activity>

</application>

</manifest>

• 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:

 package com.example.exno9;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStreamReader;

public class MainActivity extends AppCompatActivity

{

EditText e1;

Button write,read,clear; @Override

protected void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);

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

write.setOnClickListener(new View.OnClickListener()

{

@Override

public void onClick(View v)

{

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

{

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

f.createNewFile();

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

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

SDCARD”,Toast.LENGTH_LONG).show();

}

catch (Exception e)

{

Toast.makeText(getBaseContext(),e.getMessage(),Toast.LE

NGTH_LONG).show();

}

}

});

read.setOnClickListener(new View.OnClickListener()

{

@Override

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

InputStreamReader(fin));

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

{

buf += message;

}

e1.setText(buf); br.close();

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

SDCARD”,Toast.LENGTH_LONG).show();

}

catch (Exception e)

{

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

}

}

});

clear.setOnClickListener(new View.OnClickListener()

{

@Override

public void onClick(View v)

{

e1.setText(“”);

}

});

}

}

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

Output:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Result:

Thus Android Application that writes data to the SD Card is developed and executed successfully.

Home Activities:

Activity 1:

 take 10 file (5 audio and 5 text files) and perform read write operation while place them in the sd card.