Android Jetpack: Introducing WorkManager

your app won't always be in the foreground but you still need to do important background work like downloading updates and synching with your server now there are many existing api's for this each with their own particular use cases unfortunately when these api's are used incorrectly we see this

happen to save power for users Android has introduced many battery saving features and recent releases these features manage and balance the power usage of apps as a developer you need to work with these battery saving features to ensure your background tasks run across API levels this adds code

complexity but if you don't do this properly you risk your background work not running for all users this is where the work manager library comes in work manager provides a unified solution for background work taking androids power saving features and the users API level into account it's backwards

compatible to API level 14 part of android jetpack and it runs with or without Google Play services these features and more make it the recommended solution for most background work on Android there are two key attributes that make a task suitable for work manager first that the task

is deferrable and second that the test needs to be guaranteed to run deferrable work is any task which is still useful even if it's not run immediately so sending analytic data to your server is totally deferral work but sending an instant message is not deferrable guaranteed work means

that the task will run even if the app process is killed or the device restarts so a great use case for work manager would be backing up pictures to a server this work can be deferred but it should also be guaranteed to run work manager can be paired

with other api's like firebase Cloud messaging to trigger background work so for example when there's data ready to sync on your server you can use an FCM message to notify your app and then do the actual syncing with work manager while work manager is powerful background work isn't

a one-size-fits-all approach so for example while I've been talking a lot about background work when I don't mean is background threading work manager works in conjunction with but is not a replacement for calling co-routines thread pools or libraries like our extraña work manager is also not designed to

trigger work at an exact time for that you're going to need to use an API like a lar manager or start a foreground service if your users expect your task to happen immediately a complete view of modern background execution check out this blog post on the Android developer

blog which I've linked below now let me show you how to actually create and do some work let's say that I want to upload a photo using work manager first you define what your task does using a worker like this one all the code goes into the do

work method then you make a request to do this work using a class called work request as part of the work request you can add constraints specify the input and choose to run the work once or periodically the work request is basically a class for configuring when and

how your task will be run since this is non-repeating work i'm gonna go ahead and use a one-time work request I've added a constraint here that it should only do this upload when there's actually Network finally this passes in the URI of the photo as input data using

work manager's data object once you have a work request you couldnt queue it by calling work manager dot and queue and well that's it at this point I know that this photo will be uploaded at some point of the future when the network constraint is met even if

the app is closed or the phone restarts now let's say that I want the option of updated the UI when my work finishes I can use the method get work info by ID live data to get a work info live data the fact that the work info is

wrapped by live data makes it observable if you haven't used live data before you can read about it in the documentation linked below work info has all of the information about the current state of my work including the status of the work and the optional output so back

into work I could return an output and then add this live data observation code to my UI to display the output when available so what's going on behind the scenes when you in cue work as mentioned work manager is backwards compatible to API level 14 and runs without

Google Play services to ensure this work manager chooses between job scheduler and a combination of alarmmanager and broadcast receivers when running to guarantee that the work will keep running all of that information about a queued work is kept in a work manager bandaged database so that I can

be resumed if it's ever stopped now by default worker does work off of the main thread using an executor behind the scenes if you want to handle threading in some other way there's rx worker and coercion worker which are available out of the box or for even more

control you can make your old worker class by extending listenable worker and defining your exact threading strategy one area where work manager truly shines is when you create chains of dependent work let's say that I want to add a filter to multiple pictures compress those pictures together and

then batch upload the compressed file to share with the world assuming you created all of your work requests with the appropriate constraints the code to create this dependent shade of work looks like this inq the work requests in the order that I want them to run I've also

include these filter image work requests as a list which causes them to run in parallel work manager will take care of passing through the output and input in a chain so here it the output of these filter work requests will be passed as the input of the compressed

work request there is a ton more that you can do with work manager you can specify things like periodic work for work that needs to run repeatedly unique work tagged work so that you can query it or cancel related work and back off policies for retrying work for

even more features tips and tricks check out the working with work manager talk linked below so to summarize by using work manager you can and cue one-off and periodic tasks with constraints chain tasks with input and output and run these 10 tasks in parallel or sequentially display the

state of your tasks using observation and customized work managers threading strategy work manager does all of this while handling complex compatibility issues following system health best practices and guaranteeing your work will run if you're ready to get working with work manager I've linked tons of helpful documentation code

labs presentations and blog posts below happy coding you


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