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[MUSIC]

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[SOUND] Let's change
gears a little bit and

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talk about a different
kind of communication.

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Notifications, you probably know a little
bit about using Notifications from earlier

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work here at Treehouse.

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As usual check the teacher's notes for
links but

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will cover it pretty well
in this last section.

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Let's take another look at the table
we've been using in this course.

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This last row shows an example of
when we might want a notification.

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When a service needs to
send an update to the user.

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In this example we'll extend an existing
notification that shows in the drawer

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when the user is playing a song.

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Note in this list that we don't
talk about using notifications

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from an activity to the system.

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We don't need a notification in that
scenario because the activity's

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already visible to the user and
we can use a stacked bar or

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some other in app mechanism for
alerting the user to something.

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Let's start here by taking a look at
the documentation about notifications.

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First part of a notification
is the icon that appears

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in the notification bar at the top.

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Then when the user pulls the drawer down,
the notification has its own

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row in the drawer and
we can even add actions to them like this.

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This app is currently using
a notification in the player service.

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So let's check it out.

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So here in the onStartCommand method
we are using the builder pattern from

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the notification class to
build a simple notification.

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All it does is display our app's
icon when a song is playing and

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then it goes away when
the service stops playing music.

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I think it would be nice to show
the title of the song playing.

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So let's see how to do that.

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First the notification builder
has a fluent interface.

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So let's delete this semi-colon and
chain some of these things together.

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I'm gonna get rid of notification builder,
tab over and

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now at the end of this I can append
another line .setContentTitle.

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Okay how do we get the song title in here.

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We need to pass in a song
when this service is started.

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Let's go back to Main Activity.

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We're starting this service
when the play button is tapped.

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So let's look at the On Click listener
we're going to scroll all the way up

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to on create, and
here we have mplay button and

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in this listener is where we
are starting the service.

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All we need to do is add the song
as an extra to this intent.

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So we say, intent.putExtra.

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We can use the EXTRA key word SONG, and

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now for the song itself, we can just
pass in the first song in our playlist.

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Our playlist itself
isn't fully functional.

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Though that would be an interesting
exercise if you'd like to extend this and

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make it play everything in a given list.

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Anyhow, let's type Playlist.songs, and

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get the first one at index zero.

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Now a challenge for you.

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Pause me and see if you can set the song
and artist back in the service.

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Use autocomplete to help you figure
out the additional text field

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you might use for the artist name.

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Okay did you get it?

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I'm going to go back and

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let's start with some place holders
here before we build our notification.

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We have a string called title and
we'll initialize it to a blank string.

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And then a string called artist
also initialized to a blank value.

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I'm setting these to blank strings
because I'm going to do a null check and

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I'll only update them
if a song is passed in.

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I don't want the app to crash
if song data is missing.

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So for the null check,
if (intent.getParcelableExtra) and

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then we can use MainActivity.EXTRA_SONG.

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If that's not equal to null, then we can
get a song and set title and artist.

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So first, we have Song song
= intent.getParcelableExtra

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MainActivity EXTRA_SONG.

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Now we can set title equal
to song.getTitle and

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artist equal to song.getArtist.

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Now we can use these in
our notification builder.

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So for ContentTitle let's pass in title.

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And then I'm going to chain the artist
with .setContentText, and pass in artist.

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And one more thing,

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our regular app icon doesn't look
very good as a notification icon.

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So I downloaded another one.

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Let's call
R.Drawable.ic_queue_music_white.

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Okay, let's try it out.

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Okay, so we want to play some music.

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There we go.

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And look, there's our notification
showing up, and if we pull it down.

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Hey it's showing the icon,
the title, and the artist.

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Cool.

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It would be really nice to open our
app directly from this notification.

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Let's try to do that in the next video.