Cosc 4730
Android
Notifications
Plus Alarms and BroadcastReceivers
Notifications
• There are a couple of ways to notify users
without interrupting what they are doing
• The first is Toast, use the factory method
– Toast.makeText(getBaseContext(), "Text to display
to user", Toast.LENGTH_SHORT).show();
– getBaseContext() or getContext()
• Toast.LENGTH_SHORT or Toast.LENGTH_LONG is the
duration it will be displayed.
Notifications and Android APIs
• The notifications have underground a lot of
change.
– There is a completely deprecated method from
2.3.3 and below
– The newer method in 3.0 to 4.1
– 4.1+ (and popups in 5.0)
– And so much of this is used from the v4 support
library.
• Things will not look the same, but at least you can use
the same code.
Status Bar Notifications
• A status bar notification adds an icon
to the system's status bar (with an
optional ticker-text message) and an
expanded message in the
"Notifications" window.
– You can also configure the notification
to alert the user with a sound, a
vibration, and flashing lights on the
device.
• When the user selects the expanded
message, Android fires an Intent that
is defined by the notification (usually
to launch an Activity).
Basics of notifications (all APIs)
• First get the NotificationManager
– retrieve a reference to the NotificationManager with
getSystemService()
• Create a Notification object
– Min requirements are an icon, text, and time of the event.
• Note, time of event is the time currently or in past.
– For “future” events we have to use alarms, which is covered later.
• Pass it your Notification object with notify() via the
notification manager.
– Also send an ID number. This ID is used by your app, doesn’t
have to unique, but should be if you want more then one.
– The system will show your notification on the status bar and the
user will interact with it.
API 10 (2.3.3) and below
NotificationManager mNotificationManager =
(NotificationManager)
getSystemService(NOTIFICATION_SERVICE);
int icon = R.drawable.icon;
CharSequence tickerText = "Hello";
long when = System.currentTimeMillis();
Notification notification = new Notification(icon, tickerText,
when);
//send the notification
mNotificationManager.notify(ID_number, notification);
Canceling notifications
• To cancel a specific notification
mNotificationManager.cancel(ID_number);
• To cancel all of the notifications
mNotificationManager.cancelAll();
• In newer API/support library.
– .setAutoCancel(true)
• which the user clicks it, it will clear.
Adding to the notification
• To add sound
– default sound
• notification.defaults |= Notification.DEFAULT_SOUND;
– To use a different sound with your notifications, pass a
Uri reference to the sound field. The following
example uses a known audio file saved to the device
SD card:
• notification.sound =
Uri.parse("file:///sdcard/notification/ringer.mp3");
– the audio file is chosen from the internal MediaStore's
ContentProvider:
• notification.sound = Uri.withAppendedPath(
Audio.Media.INTERNAL_CONTENT_URI, "6");
Adding to the notification (2)
• Adding vibration
– To use the default pattern
• notification.defaults |= Notification.DEFAULT_VIBRATE;
– To define your own vibration pattern, pass an
array of long values to the vibrate field:
• long[] vibrate = {0,100,200,300};
• notification.vibrate = vibrate;
– You'll need to add <uses-permission
android:name="android.permission.VIBRATE"></u
ses-permission> in the AndroidManifest.xml
Adding to the notification (3)
• Adding flashing lights
– To use the default light setting, add "DEFAULT_LIGHTS" to
the defaults field:
• notification.defaults |= Notification.DEFAULT_LIGHTS;
– To define your own color and pattern, define a value for
the ledARGB field (for the color), the ledOffMS field
(length of time, in milliseconds, to keep the light off), the
ledOnMS (length of time, in milliseconds, to keep the light
on), and also add "FLAG_SHOW_LIGHTS" to the flags field:
•
•
•
•
notification.ledARGB = 0xff00ff00;
notification.ledOnMS = 300;
notification.ledOffMS = 1000;
notification.flags |= Notification.FLAG_SHOW_LIGHTS;
Adding to the notification (4)
• FLAG_AUTO_CANCEL
– flag Add this to the flags field to automatically cancel the notification after it is
selected from the Notifications window.
• FLAG_INSISTENT
– flag Add this to the flags field to repeat the audio until the user responds.
– Should be flag "uh pick me! PICK ME!"
• FLAG_ONGOING_EVENT
– flag Add this to the flags field to group the notification under the "Ongoing"
title in the Notifications window.
– This indicates that the application is on-going — its processes is still running in
the background, even when the application is not visible (such as with music
or a phone call).
• FLAG_NO_CLEAR
– flag Add this to the flags field to indicate that the notification should not be
cleared by the "Clear notifications" button
Emulator note
• Many of the additional flags do nothing with
the emulator
– There is no default sounds, it's set to silent
– no lights or vibration either, of course.
Notifications 3.0+
• We are going to use the support library at this
point, so we code everything the same.
• Note, the Action Buttons (AddAction()) will
not display on 4.1 and below.
NotificationCompat
• So you can write the “new” notifications, this
is a support library, call NotificationCompat
– This allows us to create fancy notifications, but
still work for the lower API.
How it works.
• Create a NotificationCompat.Builder object
and then once you have it configured, have it
build the notification.
– use the NotificationCompat from the support lib
v4
– import android.support.v4.app.NotificationCompat;
– import android.support.v4.app.NotificationManagerCompat;
– Side note, this also allows notifications to show up
on android wear devices as well.
Simple notification
Notification noti = new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.drawable.ic_launcher)
.setWhen(System.currentTimeMillis()) //When the event occurred, now
.setTicker("Message on status bar") //message shown on the status bar
.setContentTitle("Marquee Message") //Title message top row.
.setContentText("Icon and Message") //second row
.setContentIntent(contentIntent) //what activity to open.
.setAutoCancel(true) //allow auto cancel when pressed.
.build(); //finally build and return a Notification.
• Show the notification
nm.notify(NotID, noti);
Lights, sounds, etc.
• Just like before with can use the defaults
– .setDefaults(Notification.DEFAULT_LIGHTS |
Notification.DEFAULT_VIBRATE |
Notification.DEFAULT_SOUND);
• Or use the newer methods to choose your
own.
– setLights(int argb, int onMs, int offMs)
– setSound(Uri sound)
– setVibrate(long[] pattern)
Action Buttons
• Add the following to your notification
• addAction(int icon, CharSequence title,
PendingIntent intent)
– Icon and title for the button
– The intent should be completely different intent
from the setContentIntent(intent), so you know
which button was clicked.
• See the example code, where I have four intents for the
example with three buttons.
Expanded text
• This one we need change the style of the
notification. First use the builder to create the
default
• NotificationCompat.Builder build = new
NotificationCompat.Builder(ge …;
• Now change to another style and add more text
Notification noti = new
NotificationCompat.BigTextStyle(build)
.bigText(“…”) //lots text here.
.build();
Expanded text (2)
• And we can get something like this
Expanded with image.
• Same idea, except style is
Notification noti = new NotificationCompat.BigPictureStyle(build)
.bigPicture(BitmapFactory.decodeResource(getResources(),
R.drawable.jelly_bean))
.build();
• Note two addAction(..) methods
were added in the build.
Style of an inbox
• Inbox style and use addline and setSummaryText
Notification noti = new
NotificationCompat.InboxStyle(build)
.addLine("Cupcake: Hi, how are you?")
.addLine("Jelly Bean: Yummy")
.setSummaryText("+999 more emails")
.build();
But I want to notify a user later!
• There is no native way to that with the
notifications.
• You need to use an AlarmManager and
calendar object.
CALENDAR
Calendar object
• It a pretty simple object,
• Used briefly in the GUI demo for the date/time pickers.
• Get an intance, which has the current time set.
Calendar calendar = Calendar.getInstance();
• Use a get(..) and set(..) to change the information as needed.
– Set using the following constants Calendar.YEAR, Calendar.MONTH,
Calendar.DAY_OF_MONTH, Calendar.HOUR_OF_DAY, Calendar.MINUTE,
Calendar.SECOND
• Say I want to set the calendar to 4:40am
calendar.set(Calendar.HOUR_OF_DAY, 4);
calendar.set(Calendar.MINUTE, 40);
calendar.set(Calendar.SECOND, 0);
• As note, if it is already passed 4:40am, there would be a problem later
• Say I want to set it for 2 minutes from now.
calendar.set(Calendar.MINUTE, calendar.get(Calendar.MINUTE) +2);
ALARMMANAGER
AlarmManager
• These allow you to schedule your application to be run
at some point in the future. When an alarm goes off,
the Intent that had been registered for it is broadcast
by the system, automatically starting the target
application if it is not already running.
– We get an in AlarmManager service
• Set an intent and pendingIntent for the activity (or say a broadcast
receiver) to call.
• A time in Milliseconds when to send the intent
• And that we want a “wakeup call” at that time.
• Get the AlarmManager
– AlarmManager alarmManager = (AlarmManager)
getSystemService(ALARM_SERVICE);
Example code
• Using the calendar object for 2 minutes later.
• Create the intent and pendingIntent
Intent notificationIntent = new
Intent("edu.cs4730.notificationdemo.DisplayNotification");
PendingIntent contentIntent = PendingIntent.getActivity(MainActivity.this,
NotID, notificationIntent, 0);
• Now set the alarm
alarmManager.set(AlarmManager.RTC_WAKEUP,
calendar.getTimeInMillis(), contentIntent);
Example code (2)
• What is this:
• Intent("edu.cs4730.notificationdemo.DisplayNotification");
– We could also just give a Activity name.
• It comes from the manifest file where we describe the
activity or broadcast receiver. This case an activity.
<activity android:name=".DisplayNotification" … />
<intent-filter>
<action
android:name="edu.cs4730.notificationdemo.DisplayNotification" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
Finally!
• The displayNotification activity is called when
the alarm goes off. And it’s the
displayNotification activity that now creates
and notification.
BROADCAST RECEIVER
BroadcastReceiver
• Part of the android.content package.
– Basically a listener, but for “broadcast”
information.
• Such as sms and other broadcast data.
• Including our own broadcast intents.
• Note, you don’t have access to most screen widgets in a
broadcast receiver, except toast.
– Override the onReceive(Context, Intent) method
• The intent holds the information from the broadcast.
Note, we will come back with a full lecture on BroadcastReceiver later on as well.
BroadcastReceiver (2)
• A broadcastReceiver can be registered into
two ways:
– Context.registerReceiver() in the “main” code
• The receiver can be added and removed as needed.
– Via a receiver tag in the AndroidManifest file.
• will start up at boot.
– We use this method for simplicity.
Extend the BroadcastReceiver
public class myReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
}
}
• Intent Tells you what it is, via the get getAction() method.
AndroidManifest.xml
• We also need to add the class. This is a receiver
class so it may look something like this
<receiver android:name=".myRecv">
<intent-filter>
<action
android:name="edu.cs4730.notificationdemo.broad
Notification"/>
</intent-filter>
</receiver>
As a Note
• We could setup multiple intents to be received
by the receiver, so we normally check the
action to make sure it’s “ours”.
Example
public class myBroadcastReciever extends BroadcastReceiver {
private static final String ACTION = "edu.cs4730.notificationdemo.broadNotification";
•
@Override
public void onReceive(Context context, Intent intent) {
String info= "no bundle";
if (intent.getAction().equals(ACTION)){ //is it our action
Bundle extras = intent.getExtras();
if (extras != null) {
info = extras.getString("mytype");
if (info == null) {
info = "nothing";
}
Likely toast or start an activity or notification. Whatever is needed now.
}}}
Demo code
• notificiationDemo.zip
– notificationDemo project
• All the different notifications listed in here
– Lots of buttons to try out each one.
• Alarms and the broadcastReceiver
– notificationDemo2 project
• Need first one installed
• Sends to the broadcast receiver
• And uses an alarm to send to the broadcast receiver
• You may also find
http://developer.android.com/guide/topics/ui/no
tifiers/notifications.html helpful.
Lastly android 5 notifications.
• In Lollipop three new pieces were added.
– setVisibility() and specify one of these values:
– VISIBILITY_PRIVATE: Shows basic information, such as the
notification’s icon, but hides the notification’s full content.
– VISIBILITY_PUBLIC: Shows the notification’s full content.
– VISIBILITY_SECRET: Shows nothing, excluding even the
notification’s icon.
– addPerson(): Enables you to add one or more people
who are relevant to a notification.
– setPriority(): Marks the notification as more or less
important than normal notifications.
• Notifications with the priority field set to PRIORITY_MAX or
PRIORITY_HIGH appear in a small floating window if the
notification also has sound or vibration.
Lastly android 5 notifications (2)
• Adding the following (with
NotificationCompat)
.setPriority(Notification.PRIORITY_MAX)
.setVibrate(new long[]{1000, 1000, 1000, 1000, 1000})
– We can produce this kind of notification:
References
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http://stackoverflow.com/questions/1198558/how-to-send-parameters-from-a-notification-clickto-an-activity
http://mobiforge.com/developing/story/displaying-status-bar-notifications-android
http://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html
http://mobiforge.com/developing/story/displaying-status-bar-notifications-android
http://stackoverflow.com/questions/12006724/set-a-combination-of-vibration-lights-or-sound-fora-notification-in-android
http://developer.android.com/reference/android/app/Notification.html
http://developer.android.com/reference/android/content/BroadcastReceiver.html
http://stackoverflow.com/questions/12372654/how-to-trigger-broadcast-receiver-fromnotification
http://www.vogella.com/articles/AndroidBroadcastReceiver/article.html
Android 5 notifications information:
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http://developer.android.com/about/versions/android-5.0.html#Notifications
http://www.intertech.com/Blog/android-development-tutorial-lollipop-notifications/
Q&A