Creating Notification in Android

Notifications

A notification is an short alert  message paved in the notification panel in Android device, for ex when a SMS is received on device you see a new SMS alert in the notification panel

Using notification you can inform or alerts user about some event.

Elements of Notification

1: Content Title: title of the notification.

2: Content Text: detail of notification.

3: Icon : Icon for the notification.

Creating  Notifications

Notifications are created using NotificationCompat.Builder and NotificationManagerclass.

NotificationCompat.Builder class is used to build the notification element and NotificationManager class is used to show the notification.

Building notification

NotificationCompat.Builder mBuilder =

                                        newNotificationCompat.Builder(context)

                                        .setSmallIcon(R.drawable.icon)

                                        .setContentTitle("Notification Title”)

                                        .setContentText(“Notification detail text”);

Showing notification

// create NotificationMAnager object

NotificationManager mNotificationManager =(NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);

int notificationId=1;

// notify using NotificationManger object

mNotificationManager.notify(notificationId, mBuilder.build());

Cancelling the notification

You need to cancel a shown notification when user has seen and clicked over it after dragging the notification panel.

to cancel the displayed notification

mNotificationManager.cancel(notificationId);

Demo Application : “Showing new SMS Notification”

What we will do : we will create a SMSReceiver class which extends BroadcastReceiver class. We register this class in manifest file as a receiver for “SMS_RECEIVED“ action. The onReceive() method of SMSReceiver class will execute when a new SMS is received on device.

In onReceive()method we extract the SMS body, and SMS Sender number from the received message. We create a notification and show that a new SMS received.

Note : Do not forget the to declare the “android.permission.RECEIVE_SMS” permission and SMSReceiver in manifest file. “android.permission.RECEIVE_SMS”  permission is required to receive SMS.

AndroidManifest.xml

<?xml version="1.0"encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.notification"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="18" />

   

    <!-- Permission to Receive SMS  -->

    <uses-permission android:name="android.permission.RECEIVE_SMS"/>

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

       

        <!--  register the SMSReceiver -->

        <receiver android:name=".SmsReceiver">

            <intent-filter>

                <action android:name=

                    "android.provider.Telephony.SMS_RECEIVED"/>

            </intent-filter>

        </receiver>

    </application>

</manifest>

SMSReceiver.java

public class SMSReceiver extends BroadcastReceiver

{

    @Override

    public void onReceive(Context context, Intent intent)

    {

        //---get the SMS message passed in---

        Bundle bundle = intent.getExtras();       

        SmsMessage[] msgs = null;

        String SMSBody = "";           

        if (bundle != null)

        {

            //---retrieve the SMS message received---

           Object[] pdus = (Object[]) bundle.get("pdus");

            msgs = new SmsMessage[pdus.length];           

            for (int i=0; i<msgs.length; i++)

            {

                msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);               

                SMSBody += msgs[i].getMessageBody().toString();

            }

          // Get the Sender Phone Number

          String senderPhoneNumber=msgs[0].getOriginatingAddress();

         

        //---display the new SMS message in toast---

          Toast.makeText(context, "SMS Revived from: "+senderPhoneNumber, Toast.LENGTH_SHORT).show();

         

        /* create the notification

         * set icon, title and text

         */

          NotificationCompat.Builder mBuilder =

                      new NotificationCompat.Builder(context)

                      .setSmallIcon(R.drawable.sms)

                      .setContentTitle("New SMS Recevied from: "+senderPhoneNumber)

                      .setContentText(SMSBody);

             

        // create NotificationMAnager object

       NotificationManager mNotificationManager =

                  (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);

              int notificationId=1;

              // notify using NotificationManger object

              mNotificationManager.notify(notificationId, mBuilder.build());

             

       }                        

    }

}

Android Spinner Example

Spinner

Spinner is a widget which provides a quick way to select a value from a set. A spinner presents multiple options/items to the user from which user can select one option.

For ex.  In game application when we want user to select a particular level he/she wants to play, we can use spinner to multiples levels in which can select one level.

Using Spinner

Steps to use spinner in your application

1: Defining the spinner in your .xml/layout file by using “Spinner” tag

<!—Declaring Spinner in xml -->

    <Spinner

        android:id="@+id/spinner"

        android:layout_marginTop="20dp"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:prompt="@string/spinner_title"

    />

2: Create an array/arraylist of strings that will be set as the items of spinner.

String spinnerItems[]={"Level 1","Level 2","Level 3","Level 4","Level 5",};

3: Create adapter and set it with spinner

// Create adapter for spinner

ArrayAdapter  dataAdapter = newArrayAdapter(this, android.R.layout.simple_spinner_item, spinnerItems);

// attaching data adapter to spinner

mySpinnerObject.setAdapter(dataAdapter);

4: Set  clicklistener on Spinner

// set clicklisteneron Spinner

 mySpinnerObject.setOnItemSelectedListener(this);

5: override  onItemSelected() method, this method gets called by the System when an item is selected. This method receives the position parameter which signifies the index of the array/arraylist which is selected by the user.

@Override

 public voidonItemSelected(AdapterView<?> parent, View view, intposition, long id)

{

                         

// get the selected Spinner's Item

            String itemSelected = parent.getItemAtPosition(position).toString();

}

Let put all this together and develop an android application to learn how to use spinner.

Demo Application: “Working with Spinner”

What we will do: We will present a list of levels “Level 1,Level 2,Level 3,Level 4,Level 5" to the user and show the level selected by the user using Toast.

activity_main.xml

<?xml version="1.0"encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical"

    android:padding="10dip"

    android:layout_width="fill_parent"

    android:layout_height="wrap_content">

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="Select the Level"

        android:layout_marginTop="20dp"

        android:textColor="#0000FF"

        android:textSize="20dp"

        android:textStyle="bold"

    />

    <!-- Spinner Element -->

    <Spinner

        android:id="@+id/spinner"

        android:layout_marginTop="20dp"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

    />

  </LinearLayout>

SpinnerMainActivity.java

public classSpinnerMainActivity extends Activity implementsOnItemSelectedListener

{

     Spinner mySpinner;

      /* create array of string of levels

     * to be set as Spinner Item

     */

    String spinnerItems[]={"Level 1","Level 2","Level 3","Level 4","Level 5",};

   

     @Override

     protected void onCreate(Bundle savedInstanceState)

     {

          super.onCreate(savedInstanceState);

          setContentView(R.layout.activity_main);

         

          // get the Spinner reference

               mySpinner = (Spinner) findViewById(R.id.spinner);

       

               // set clicklistener on Spinner

               mySpinner.setOnItemSelectedListener(this);

       

              // Create adapter for spinner

          ArrayAdapter  dataAdapter = new ArrayAdapter(this, android.R.layout.simple_spinner_item, spinnerItems);

          // Drop down layout style - list view with radio button

                    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

          // attaching data adapter to spinner

          mySpinner.setAdapter(dataAdapter);

     }

     /* onItemSelected() method gets called by the System

      * when an item is selected

      * This method receives the position parameter

      * which signifies the index of the array

      * which is selected

      */

     @Override

        public voidonItemSelected(AdapterView<?> parent, View view, int position, long id)

        {

           

              // get the selected Spinner's Item

              String itemSelected = parent.getItemAtPosition(position).toString();

              // Showing selected spinner item

              Toast.makeText(getApplicationContext(),  itemSelected+"  Selected", Toast.LENGTH_LONG).show();

          }

      

      

       @Override

          public void onNothingSelected(AdapterViewview)

          {

              // TODOAuto-generated method stub

          }

}