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Foreground Services
4:21In this video we’ll learn about foreground Services and how to use them!
When you play music on your phone, it's
typically accompanied by a notification.
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This notification usually tells
you what song is playing and
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provides some basic functionality,
like play and pause.
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But this notification also
serves another purpose.
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If you want your service
to run in the foreground,
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then you need to have a notification.
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A foreground service is a service
that the user is actively aware of.
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Thus a foreground service
is given special priority
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when Android encounters
low memory situations.
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Remember the various levels
of importance for processes?
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Well, when we designate our
service as a foreground service,
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it's automatically part of the top group,
foreground processes.
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And it's extremely unlikely that our
services process will be killed.
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To make our service a foreground service,
all we need to do is call start
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foreground from our service and
provide a notification along with an id.
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Let's see how to do that.
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Let's start mPlayerService by creating
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a notification.builder object
at the top of OnStart command.
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Notification.Builder and
let's call it notificationBuilder and
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set it equal to new Notification.Builder,
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and pass in this for the context.
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Next let's call
setSmallIcon on our builder
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and pass in R.mipmap.ic_launcher
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to set our notifications icon to be
the default icon included in our app.
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Then let's create a new notification,
Notification, and
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we'll call it notification and
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set it equal to notificationBuilder.build.
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Next let's call startForeground and
pass an 11 for
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the first parameter and
our notification for the second.
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The first parameter is
an id that we choose,
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we just need to not reuse
notification ids in the same app.
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Since this is our only notification, we'll
be fine just picking any random number,
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like 11, just don't pick zero,
that's not allowed.
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Lastly, if the music is done playing
we can stop running in the foreground.
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Let's call stopForeground
right below stopSelf and
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pass in true to make sure that
we remove the notification.
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And that's it, that's all you need to do
to run your service in the foreground.
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If we were making a more finished product,
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we might want to add some buttons to our
notification and update our app icon.
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But we're not, so
let's go ahead and test the app and
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see what a foreground service looks like.
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But before we get to testing,
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it looks like there's an error
with this call to build.
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It looks like this call
requires API 16 but
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our current min is 15,
down here at the bottom left.
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Let's open our app's
build.gradle file to fix this.
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And set minSdkversion to 16,
and then sync now.
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And if we go back to player service,
no more errors.
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Let's get back to testing the app.
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And if we play the music,
there's our notification.
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And if we quit the activity,
the notification is still there.
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And if we wait for the song to end,
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we could even watch our notification
disappear because the service was stopped,
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and it triggers the stop
foreground method.
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Fantastic work.
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This is definitely some of the most
difficult material in Android,
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and you should be extremely proud for
finishing this course.
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Keep practicing and I'll see you soon.
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