Jul 31, 2013

Android NotificationListenerService Example

Standard
Introduction
NotificationListenerService is introduced in Android 4.3 (API 18). It allows an application to receive information about notifications as it creates or removes. NotificationListenerService class is derived from the Service class. It has two abstract methods namely 1. onNotificationPosted 2. onNotificationRemoved.  
To use NotificationListenerService, we need to create a java file which extends NotificationListenerService and implement two callback methods. Both methods have a parameter named "sbn", which is an object of StatusBarNotification class. StatusBarNotification provides necessary information about Notifications.

NotificationListenerService provides facility to fetch active notifications using getActiveNotifications and also provides a feature to remove notifications using cancelAllNotifications. 

Useful Methods
1. NotificationListenerService
    onNotificationPosted()
    onNotificationRemoved()
    cancelAllNotifications()
    getActiveNotifications()
2. StatusBarNotification
    getId()
    getNotification()
    getPackageName()
    getPostTime()
    isClearable()
    isOngoing()

Note
User require to enable notification permission from "Settings > Security > Notification access".

Source Code of NotificationListenerService
Worth to see the source code, If you hare curious. It has two java files and two AIDL files 
https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/java/android/service/notification

Example
This is simple example of NotificationListenerService, It has simple UI contain three buttons and one textview. 

  • Create Notification - It will create simple notification so that we can test onNotificationPosted event
  • Clear All Notification - It will create all notification in notificationbar
  • List of Notification - It will display notification list in textview
  • TextView - display notification events and list of notification.

This example has Activity, Service and BroadcastReceiver. BroadcastReceiver used for communication between activity and service. We can't access cancelAllNotifications() and getActiveNotifications() methods from activity directly so I use BroadcastReceivers.

Screenshots



Source Code

1. MainActivity.java
package com.kpbird.nlsexample;

import android.app.Activity;
import android.app.NotificationManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v4.app.NotificationCompat;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends Activity {

    private TextView txtView;
    private NotificationReceiver nReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txtView = (TextView) findViewById(R.id.textView);
        nReceiver = new NotificationReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
        registerReceiver(nReceiver,filter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(nReceiver);
    }



    public void buttonClicked(View v){

        if(v.getId() == R.id.btnCreateNotify){
            NotificationManager nManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            NotificationCompat.Builder ncomp = new NotificationCompat.Builder(this);
            ncomp.setContentTitle("My Notification");
            ncomp.setContentText("Notification Listener Service Example");
            ncomp.setTicker("Notification Listener Service Example");
            ncomp.setSmallIcon(R.drawable.ic_launcher);
            ncomp.setAutoCancel(true);
            nManager.notify((int)System.currentTimeMillis(),ncomp.build());
        }
        else if(v.getId() == R.id.btnClearNotify){
            Intent i = new Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_SERVICE_EXAMPLE");
            i.putExtra("command","clearall");
            sendBroadcast(i);
        }
        else if(v.getId() == R.id.btnListNotify){
            Intent i = new Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_SERVICE_EXAMPLE");
            i.putExtra("command","list");
            sendBroadcast(i);
        }


    }

    class NotificationReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            String temp = intent.getStringExtra("notification_event") + "n" + txtView.getText();
            txtView.setText(temp);
        }
    }



}

2. NLService.java
package com.kpbird.nlsexample;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.service.notification.NotificationListenerService;
import android.service.notification.StatusBarNotification;
import android.util.Log;

public class NLService extends NotificationListenerService {

    private String TAG = this.getClass().getSimpleName();
    private NLServiceReceiver nlservicereciver;
    @Override
    public void onCreate() {
        super.onCreate();
        nlservicereciver = new NLServiceReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction("com.kpbird.nlsexample.NOTIFICATION_LISTENER_SERVICE_EXAMPLE");
        registerReceiver(nlservicereciver,filter);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        unregisterReceiver(nlservicereciver);
    }

    @Override
    public void onNotificationPosted(StatusBarNotification sbn) {

        Log.i(TAG,"**********  onNotificationPosted");
        Log.i(TAG,"ID :" + sbn.getId() + "t" + sbn.getNotification().tickerText + "t" + sbn.getPackageName());
        Intent i = new  Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
        i.putExtra("notification_event","onNotificationPosted :" + sbn.getPackageName() + "n");
        sendBroadcast(i);

    }

    @Override
    public void onNotificationRemoved(StatusBarNotification sbn) {
        Log.i(TAG,"********** onNOtificationRemoved");
        Log.i(TAG,"ID :" + sbn.getId() + "t" + sbn.getNotification().tickerText +"t" + sbn.getPackageName());
        Intent i = new  Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
        i.putExtra("notification_event","onNotificationRemoved :" + sbn.getPackageName() + "n");

        sendBroadcast(i);
    }

    class NLServiceReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent.getStringExtra("command").equals("clearall")){
                    NLService.this.cancelAllNotifications();
            }
            else if(intent.getStringExtra("command").equals("list")){
                Intent i1 = new  Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
                i1.putExtra("notification_event","=====================");
                sendBroadcast(i1);
                int i=1;
                for (StatusBarNotification sbn : NLService.this.getActiveNotifications()) {
                    Intent i2 = new  Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
                    i2.putExtra("notification_event",i +" " + sbn.getPackageName() + "n");
                    sendBroadcast(i2);
                    i++;
                }
                Intent i3 = new  Intent("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
                i3.putExtra("notification_event","===== Notification List ====");
                sendBroadcast(i3);

            }

        }
    }

}

3. activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Create Notification"
            android:id="@+id/btnCreateNotify"
            android:onClick="buttonClicked"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"/>



    <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Clear All Notification"
            android:id="@+id/btnClearNotify"
            android:onClick="buttonClicked"
            android:layout_below="@+id/btnCreateNotify"
            android:layout_alignLeft="@+id/btnCreateNotify"
            android:layout_alignRight="@+id/btnCreateNotify"/>

    <ScrollView android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_alignParentBottom="true"
                android:layout_alignRight="@+id/btnListNotify"
                android:layout_below="@+id/btnListNotify"
                android:layout_alignLeft="@+id/btnListNotify">

        <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="NotificationListenerService Example"
                android:id="@+id/textView"
                />


    </ScrollView>

    <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="List of Notification"
            android:id="@+id/btnListNotify"
            android:onClick="buttonClicked"
            android:layout_below="@+id/btnClearNotify"
            android:layout_alignLeft="@+id/btnClearNotify"
            android:layout_alignRight="@+id/btnClearNotify"/>
</RelativeLayout>

4. AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.kpbird.nlsexample"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="18"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.kpbird.nlsexample.MainActivity"
            android:label="@string/app_name"
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:name="com.kpbird.nlsexample.NLService"
                 android:label="@string/app_name"
                 android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
            <intent-filter>
                <action android:name="android.service.notification.NotificationListenerService" />
            </intent-filter>
        </service>
    </application>

</manifest>



User following code to open Notification Access setting screen
Intent intent=new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
startActivity(intent);

Download Source Code from GitHub 

10 comments:

  1. Ajit Gevariya8:18 PM

    i implemented this example but onNotificationPosted or removed is not going to called.. wired!

    Might be service is not going to bind properly.. any clue??

    ReplyDelete
  2. kpbird9:45 AM

    User require to enable notification permission from "Settings > Security > Notification access".



    Can you please verify security setting ?

    ReplyDelete
  3. I can't help but notice that there is a persistent bug...

    When using the code, if you go and enable notification via the:

    Intent intent=new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
    startActivity(intent);

    Then never call that again (meaning you have enabled notifications but do not call that intent/method again) you are left in a state where the service never binds.

    Meaning no notifications work.

    More over - if you do leave those methods in place, you will see the check box is checked and that kpbird has enabled notifications ... Yet because it was already checked, you never bind the service again.

    I have been struggling with a workaround for this, and have tried even manually binding this, but that eventually results in notifications just never working again...

    What did you do to resolve this?

    ReplyDelete
  4. John Kim7:21 PM

    I ran your example in ADT Eclipse debugger and NLService is not getting created ( I put a breakpoint in onCreate() ). Am I missing something? Thanks

    ReplyDelete
  5. Read what I wrote underneath - same issue.

    ReplyDelete
  6. Tuan Tran1:17 AM

    I do not see Settings > Security > Notification access in Android KK. Does anyone know if there a restrictions with NotificationListenerService in KK?

    ReplyDelete
  7. Robert Pérez3:45 PM

    Is possible to verify in the app if the user has allowed the permission?
    Thanks

    ReplyDelete
  8. Add another button in your activity_main.xml file called btnGrant and then add this code to the MainActivity:
    else if(v.getId() == R.id.btnGrant){
    Intent i = new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
    startActivity(i);
    }

    This will allow you to go to the otherwise hidden option.

    ReplyDelete
  9. Thank you for posting this.

    ReplyDelete
  10. Hugo Garcia-Cotte1:48 PM

    Any solution to this issue ?

    ReplyDelete