Coding effectively using the ‘MAD’ methodology

A definitive guide by Android developers

Background Processing with Work Manager

Our first speaker, Fedor Erofeev opened the meetup by talking about Background Processing With Work Manager in which he taught us about the best practices of scheduling one-time and periodic background work with Jetpack Work Manager.

There is no doubt that background processing is one of the hardest topics to talk about in Android. Google recommended Jetpack WorkManager to handle background processing. Fedor also recommended to use WorkManager because it has some benefits, which are:

• Guaranteed: The work is guaranteed to execute.

• Work constraints: Specify best conditions for work. For example:
  • When the device is using Wi-Fi
  • The device is charging
  • The device is idle
  • Etc.
• Flexible scheduling: One-time and repeated work:
• • Can be delayed
  • Minimum period between repeated work — 15 minutes
• Retry policies: Provide retry policies in case there are some errors during execution.
• Work chaining:Chain multiple works in specific order with specific constraints.
• Works with RxJava and Coroutines.

• Built-in functionality for long work:Run in the foreground and show notifications while the worker does the work.

• Integration with Hilt: Easily inject dependencies using only 3 annotations:
  • @HiltWorker, @AssistedInject, @Assisted

However there are no perfect tools. WorkManager also have some disadvantages, these are…

• Not precise: Repeated work is executed depending on various conditions and can be delayed by some time.
• Fast work doesn’t show notifications: The built-in functionality for notifications automatically removes the notification once the job is done. If your work is quick there is a big chance the notification will not appear at all (possible to use regular notification in this case).

After we understand the Advantages and disadvantages of WorkManager, we need to know when to use it. According to Fedor there are two types of time when we need to know when to use WorkManager. These are one time or periodic. For one-time work you can choose expedited
mode which is available in work manager 2.7 where this means this work will be executed faster than regular work and it will be less affected by device workload and other limitations. For periodic work or long-running work there is a functionality that let us to run work in the context of a foreground server service and it will show you a notification that will be automatically dismissed after some time once the work is done and deferrable uh which means that it will be executed sometime in the future and we can just do the work without any notification.

After we understand about the right time to use the WorkManager, now is the time to know how to use it.

The first step to use WorkManager is to create a worker. After the first step is done, the next step is to create work requests. In the work requests there are two types; One time work requests or Periodic work requests.

To understand more about how to create work requests for both One time work requests and periodic work requests , watch Fedor deep explanation in our YouTube channel.

How to use “Tools Attributes”?

We have to add “tools namespace” in our “root element” of the XML file that we want to use. Add “tools” and the auto suggestion will come up.

Here are some useful tools attributes examples that will help you work faster as they will not affect the APK size but still visible in layout preview.

tools:text

From the images above, there are 2 Textviews here, the first one is ‘first name’ which he saved it as android:text=”James” and the second one is ‘last name’ which uses tools:text=”Bond”.

As you can see in the layout preview, there are both ‘James’ and ‘Bond’, but when we run it, we can only see ‘James’. Tools attributes will not show up on the emulator or real devices meaning that only the first name, ‘James’, will be shown here.

Both tools text and android text can be set in the same textview.

For example, this last name is set to android:text=”Cameron” and tools:text=”Bond”. In the layout preview, ‘Bond’ will be visible because tools text is the main priority, but when the system is run, tools text will be deleted and replaced with ‘Cameron’.

tools:visibility 

tools:listitem

Many Android developers are probably familiar with “RecyclerView” and might face some difficulty when checking the item in it. Usually, you have to run the program to see the result which could take up to many minutes, however, using tools:listitem will allow you see the items in the preview saving quite a lot of time. We have to set it as tools:listitem=”@layout/item_person”. The example here is RecyclerView’s items and on the right side is the preview with a list of names.

tools:itemCount

In RecyclerView, we can set the number of items that we would like to see in the preview by using tools:itemCount=”5″. From the example, it was set to 5, however, it can be change to any number you prefer.

Sample Data

In the case that we want to set text or images to the preview but do not have the content yet, sample data from Android Studio can be used to fill those gaps.

Here are some examples of the attributes.

1) Image View

Image view is used together with data binding. Normally, we have to wait for the information from the API before setting the data binding and checking the visibility in the emulator which takes a lot of time. With this tool, we can set a sample avatar by using tools:src @tools:sample/avatars and the program will randomly pick avatars from the Android Studio.

2) Full Name

After we have the image, it’s full name’s turn. Android Studio also provides us some names. Similar to  avatars, type @tools:sample/full_names to randomly pick the name. When we go to the RecyclerView, both random names and avatar will be shown. This can only be seen in the layout preview and will not affect the emulator or the real program and it can save a lot of time from running the application.

3) Text Lorem

In the case that we have textview but no content to fill it yet, we can use tools:text=”@tools:sample/lorem” or tools:text=”@tools:sample/lorem/random” for a longer text. The steps are simple, type “tools” and there will be a pop-up dialogue to choose — it’s not necessary to remember all the commands. The text lorem will be updated after we set the tools attribute, and will be visible in the RecyclerView.

Customized Sample Data

To add the customized data, open the directory and right click at sample data > new > file. Then, the “register new file type association” window will pop-up. Type the file name that you want and choose “text”. From the example, “Fruits” is used as the file name and the list is fruit names. To use the custom sample data, type tools:text=”@sample/fruits”, then the fruit names will be randomly selected to show on the RecyclerView. Super easy!

If you want to learn more about tools attributes, you can visit Android official website.