In this part of my Android video tutorial I’ll cover the NotificationManager, TaskStackBuilder, PendingIntent, AlarmManager and more on Intents.

The focus this time is on being able to notify the user of events even if my app isn’t running. The code is set up so that you can easily copy and paste out the capabilities you need directly into your app. All of the code follows the video below with a ton of comments to help.

If you like videos like this it helps to tell Google Plus with a click here [googleplusone]

Code From the Video

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="match_parent"
        android:layout_height="wrap_content"
        android:text="Show Notification"
        android:id="@+id/showNotificationBut"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:onClick="showNotification"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Stop Notification"
        android:id="@+id/stopNotificationBut"
        android:layout_below="@+id/showNotificationBut"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:onClick="stopNotification"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Alert in 5 Seconds"
        android:id="@+id/alertButton"
        android:layout_below="@+id/stopNotificationBut"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:onClick="setAlarm"/>

</RelativeLayout>

MainActivity.java

package com.newthinktank.derekbanas.notificationex;

import android.app.AlarmManager;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.TaskStackBuilder;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.NotificationCompat;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.Button;

import java.util.GregorianCalendar;

// NotificationManager : Allows us to notify the user that something happened in the background
// AlarmManager : Allows you to schedule for your application to do something at a later date
// even if it is in the background

public class MainActivity extends ActionBarActivity {

    Button showNotificationBut, stopNotificationBut, alertButton;

    // Allows us to notify the user that something happened in the background
    NotificationManager notificationManager;

    // Used to track notifications
    int notifID = 33;

    // Used to track if notification is active in the task bar
    boolean isNotificActive = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Initialize buttons
        showNotificationBut = (Button) findViewById(R.id.showNotificationBut);
        stopNotificationBut = (Button) findViewById(R.id.stopNotificationBut);
        alertButton = (Button) findViewById(R.id.alertButton);

    }


    public void showNotification(View view) {

        // Builds a notification
        NotificationCompat.Builder notificBuilder = new NotificationCompat.Builder(this)
                .setContentTitle("Message")
                .setContentText("New Message")
                .setTicker("Alert New Message")
                .setSmallIcon(R.drawable.ntt_logo_24_24);

        // Define that we have the intention of opening MoreInfoNotification
        Intent moreInfoIntent = new Intent(this, MoreInfoNotification.class);

        // Used to stack tasks across activites so we go to the proper place when back is clicked
        TaskStackBuilder tStackBuilder = TaskStackBuilder.create(this);

        // Add all parents of this activity to the stack
        tStackBuilder.addParentStack(MoreInfoNotification.class);

        // Add our new Intent to the stack
        tStackBuilder.addNextIntent(moreInfoIntent);

        // Define an Intent and an action to perform with it by another application
        // FLAG_UPDATE_CURRENT : If the intent exists keep it but update it if needed
        PendingIntent pendingIntent = tStackBuilder.getPendingIntent(0,
                PendingIntent.FLAG_UPDATE_CURRENT);

        // Defines the Intent to fire when the notification is clicked
        notificBuilder.setContentIntent(pendingIntent);

        // Gets a NotificationManager which is used to notify the user of the background event
        notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        // Post the notification
        notificationManager.notify(notifID, notificBuilder.build());

        // Used so that we can't stop a notification that has already been stopped
        isNotificActive = true;


    }

    public void stopNotification(View view) {

        // If the notification is still active close it
        if(isNotificActive) {
            notificationManager.cancel(notifID);
        }

    }

    public void setAlarm(View view) {

        // Define a time value of 5 seconds
        Long alertTime = new GregorianCalendar().getTimeInMillis()+5*1000;

        // Define our intention of executing AlertReceiver
        Intent alertIntent = new Intent(this, AlertReceiver.class);

        // Allows you to schedule for your application to do something at a later date
        // even if it is in he background or isn't active
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

        // set() schedules an alarm to trigger
        // Trigger for alertIntent to fire in 5 seconds
        // FLAG_UPDATE_CURRENT : Update the Intent if active
        alarmManager.set(AlarmManager.RTC_WAKEUP, alertTime,
                PendingIntent.getBroadcast(this, 1, alertIntent,
                        PendingIntent.FLAG_UPDATE_CURRENT));

    }
}

more_info_notific.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">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Info on the notification"
        android:id="@+id/textView"
        android:textSize="16sp"/>

</LinearLayout>

MoreInfoNotification.java

package com.newthinktank.derekbanas.notificationex;

import android.app.Activity;
import android.os.Bundle;

// Called when the notification is clicked on in the task bar
public class MoreInfoNotification extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.more_info_notific);
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.newthinktank.derekbanas.notificationex" >

    <!-- Permission to use AlarmManager -->
    <uses-permission android:name="com.android.alarm.permission.SET_ALARM"/>
    <!-- Permission to Send SMS -->
    <uses-permission android:name="android.permission.SEND_SMS"/>

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MoreInfoNotification"
            android:label="More on notification"
            android:parentActivityName=".MainActivity">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity"/>
        </activity>

        <receiver android:name=".AlertReceiver"/>
    </application>

</manifest>

AlertReceiver.java

package com.newthinktank.derekbanas.notificationex;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.support.v4.app.NotificationCompat;

public class AlertReceiver extends BroadcastReceiver{

    // Called when a broadcast is made targeting this class
    @Override
    public void onReceive(Context context, Intent intent) {

        createNotification(context, "Times Up", "5 Seconds Has Passed", "Alert");

    }

    public void createNotification(Context context, String msg, String msgText, String msgAlert){

        // Define an Intent and an action to perform with it by another application
        PendingIntent notificIntent = PendingIntent.getActivity(context, 0,
                new Intent(context, MainActivity.class), 0);

        // Builds a notification
        NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(context)
                        .setSmallIcon(R.drawable.ntt_logo_24_24)
                        .setContentTitle(msg)
                        .setTicker(msgAlert)
                        .setContentText(msgText);

        // Defines the Intent to fire when the notification is clicked
        mBuilder.setContentIntent(notificIntent);

        // Set the default notification option
        // DEFAULT_SOUND : Make sound
        // DEFAULT_VIBRATE : Vibrate
        // DEFAULT_LIGHTS : Use the default light notification
        mBuilder.setDefaults(Notification.DEFAULT_SOUND);

        // Auto cancels the notification when clicked on in the task bar
        mBuilder.setAutoCancel(true);

        // Gets a NotificationManager which is used to notify the user of the background event
        NotificationManager mNotificationManager =
                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        // Post the notification
        mNotificationManager.notify(1, mBuilder.build());

    }
}