Good Morning, It’s your captain speaking. Welcome aboard the Developer’s Commute. Today we have Core Android Concepts, some interesting tweets, articles, motivation and in the end, Coding Motivation to keep you moving We hope that you enjoy this ride with us and you have a pleasant journey ahead.

Android Core Concepts

Explaining the Work Manager

Have you ever wondered, how an app uploads your image to the server even if it is closed by the user?

If an app is killed by the Android OS due to a lack of memory can I still upload my image?

It is an interesting question to think about.

How does an app upload or update something even when it is closed by the user or OS?

The answer is simple: Work Manager

But there is more to a work manager than meets the eye.

In today's newsletter, we explore more about work managers and try to find their inner workings. Let’s get started with the definition of a Work Manager.

Work Manager is an Android Jetpack Library that allows developers to run deferrable guaranteed tasks in the background when certain constraints are met. What do we exactly mean by that?

Let's try to understand its definition and when to use workmanager.

→ It is used for guaranteed deferrable tasks:

• Deferrable means that the work manager is used for the tasks that do not require immediate execution, instead, they can be carried out later on.

• Guaranteed means that these tasks are important to execute so they need to be executed no matter what.

• Let me give you an example: If you are trying to upload an image on Instagram and suddenly you receive a call. The Instagram app will go in the background. Now it is possible that the app gets closed by Android OS or stays in the background. If it gets closed by the Android OS, then whenever the user opens the app, it will resume uploading the image. If it is available in the background then the app will continue uploading the image in the background.

• In one case the tasks get deferred to whenever the user opens the app whereas in the other case, the tasks will continue in the background. The ultimate goal is to upload the image, which is guaranteed. But, it can be deferred if it is not possible at this exact moment.

→ When constraints are met:

• The background tasks will only continue if the constraints are met.

• We do not need to keep on uploading the image if the internet is not available. As soon as the internet becomes available we will continue the task. So the internet here is a constraint.

→ When to use WorkManager:

• Here is an interesting image from this blog post that might help you understand the concept of work manager better.

  

• If you are running a background task that is locally deferrable work and sync then use the Work Manager

• If you are running a background task that is triggered online use Firebase Cloud Messaging and Work Manager

• If you are running a task that is a high priority then run it as a foreground services

• If the task needs to be set at an exact time then use Alarm Manager

Benefits of using Work Manager:

• Handles compatibility with different OS versions

• Follows system health

• Supports asynchronous tasks

• Supports chained tasks

• Lets you set constraints

• Guarantees execution of tasks

How does the Work Manager work with different OS versions?

→ If the Work manager finds API 23+ then it uses a job scheduler else it uses a Broadcast receiver with Alarm Manage

How do the internals of a Work Manager work?

→ Internal Task Executor is a single-threaded executor that handles all the tasks.

→ WorkManager Database is a database that contains all the information on the tasks and keeps track of their status. It includes all input outputs and constraints. It is what guarantees that the task will be executed even if the app is closed.

→ WorkFactory creates these workers.

→ Default executor that runs the task on the main thread until you specify otherwise.

hen your work request enqueues the work it goes to the internal task executor. The internal task executor saves the database. When constraints are met, the internal task executor tells the work manager to produce a worker. The work executes dowork() on the main thread. That is how tasks are executed.

In the next newsletter, we will try to code our work manager. For now, this is for the newsletter. I hope you enjoyed this newsletter. If I have made some mistake. Please forgive me.

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Developer Motivation

Goodbye Fellow Developer

I hope you enjoyed this Developer’s Commute. Thank you for joining me.

Your Captain- Hitesh Kohli