Android- Continuously check for a new record in the database and generate a notification providing the details of the new entry

Question

I am trying to create an android application that continuously check for a new record in a remote database and provide a notification if a new record is added. i want to repeat this for every record that is added.

I have done the following till now Created a service that fetches data from the database. Can anyone suggest what's the best way to call the service again and again after a fixed interval or keep the service up and running and cal a method repeatedly. What would prove a better performance?

Answer 1

Continuously checking for a new record in a remote database will create a load in your application.

You can use Google Cloud to device messaging service. This will send a notification message to device every time the remote database has new records.

Please check this : http://developer.android.com/google/gcm/index.html

Steps for GCM

1.Add following permission and receiver in AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />

<permission android:name="com.example.test.permission.C2D_MESSAGE" 
    android:protectionLevel="signature" />
<uses-permission android:name="com.example.test.permission.C2D_MESSAGE" />

 <receiver
        android:name="com.example.test.MyBroadcastReceiver"
        android:permission="com.google.android.c2dm.permission.SEND" >
        <intent-filter>
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
            <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
            <category android:name="com.example.test" />
        </intent-filter>
    </receiver>

Note: find and replace com.example.test with your package name

1. MyBroadcastReceiver.java

   public class MyBroadcastReceiver extends BroadcastReceiver{
   
       private static final String TAG = "GCM";
       MyPrefs myPrefs ;
   
   @Override
   public void onReceive(Context context, Intent intent) {
   
   myPrefs = new MyPrefs(context);
   
   Log.d(TAG,"inside onReceive");
   
   String action = intent.getAction();
   if (action.equals("com.google.android.c2dm.intent.REGISTRATION")) {
   
       handleRegistration(context,intent);
   } else if (action.equals("com.google.android.c2dm.intent.RECEIVE")) {
   
   
       handleMessage(context,intent);
   }
   }
   private void handleRegistration(Context context,Intent intent) {
   String registrationId = intent.getStringExtra("registration_id");
   String error = intent.getStringExtra("error");
   String unregistered = intent.getStringExtra("unregistered");       
   
   // registration succeeded
   if (registrationId != null) {
       Log.d(TAG, "Device_reg_id : "+registrationId);
   
       // store registration ID on shared preferences
       myPrefs.putString("DEVICE_REG_ID", registrationId);
   
       // notify 3rd-party server about the registered ID
       generateNotification(context, "Registration Sucessful", "Device register sucessfully!");
   }
   
   // unregistration succeeded
   if (unregistered != null) {
       // get old registration ID from shared preferences
       // notify 3rd-party server about the unregistered ID
   } 
   
   // last operation (registration or unregistration) returned an error;
   if (error != null) {
       if ("SERVICE_NOT_AVAILABLE".equals(error)) {
           // optionally retry using exponential back-off
           // (see Advanced Topics)
       } else {
           // Unrecoverable error, log it
           Log.i(TAG, "Received error: " + error);
       }
   }
   }
   private void handleMessage(Context context, Intent intent) {
   
   String data = intent.getExtras().getString("data");
   generateNotification(context, "New Message is received", data);
   }
   
   private void generateNotification(Context context,String title,String text) {
   
   NotificationCompat.Builder mBuilder = 
           new NotificationCompat.Builder(context)
           .setSmallIcon(R.drawable.ic_launcher)
           .setContentTitle(title)
           .setContentText(text);
   
   // Creates an explicit intent for an Activity in your app
   Intent resultIntent = new Intent(context, MainActivity.class);
   
   PendingIntent resultPendingIntent = PendingIntent.getBroadcast(context,0,resultIntent, 0);     
   mBuilder.setContentIntent(resultPendingIntent);
   
   NotificationManager mNotificationManager =
       (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
   // mId allows you to update the notification later on.
   mNotificationManager.notify(0, mBuilder.build());
    }
   

2. MainActivity.java

   public class MainActivity extends Activity {
   
    String device_reg_id;
   
    @Override
    public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   
   MyPrefs prefs = new MyPrefs(this);
   device_reg_id = prefs.getString("DEVICE_REG_ID"); 
   
   if (device_reg_id == null )
   {
       Log.d("GCM", "Registration start");
       // registration 
       Intent registrationIntent = new Intent("com.google.android.c2dm.intent.REGISTER");
       // sets the app name in the intent
       registrationIntent.putExtra("app", PendingIntent.getBroadcast(this, 0, new Intent(), 0));
       registrationIntent.putExtra("sender", "1850XXXX2785");
       startService(registrationIntent);
   }else
   {
       // send a message to device its self
   
           String api_key = "AIzaSyBXSJHPqFiYeYdAoYfN1XlI20Es";
   
           Sender sender = new Sender(api_key);
   
           Message message = new Message.Builder()
           .collapseKey("1")
           .timeToLive(3)
           .delayWhileIdle(true)
           .addData("data", "Welcome!")
           .build();
   
           Result result;
           try {
               result = sender.send(message, device_reg_id, 5);
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
         }
       }
     }
   

3. MyPrefs.java

   public class MyPrefs {
   
    private SharedPreferences sp;
    private Editor editor;
   
    public MyPrefs(Context context){
           sp = PreferenceManager.getDefaultSharedPreferences(context);
           editor = sp.edit();
    }
   public void putString(String key,String Value){
             editor.putString(key,Value);
             editor.commit();
   }
   public String getString(String key){
          return sp.getString(key,null);
    }
   }
   

Note don't forget to import gcm-server.jar from sdk\extras\google\gcm\gcm-server\dist. if you don't find the path in sdk than install Google Cloud Messaging for Android Libaray under Extras in Android SDk Manager