android article jetpack Other Android Tutorials Tech Tools & Libraries

Introduction to Android Jetpack

Introduction to Android Jetpack

Introduction to Android Jetpack

Most Android apps now use the help libraries to assist customers add all types of up to date widgets and to tackle compatibility points throughout Android units and OS variations. You’d be hard-pressed to discover an Android app that doesn’t use one thing from them, they usually’re included as a dependency in template tasks made in Android Studio. Widgets as elementary as RecyclerView are included in them.

The help libraries are nice to use, however they’ve advanced fairly a bit through the years and the names have turn out to be considerably complicated. There are and, for instance. Wanting on the names alone, have you learnt what courses are in them? The names are supposed to designate what model of Android they help, however, as they’ve advanced, the minimal model has elevated to API Degree 14.

Google has realized that this number of ever-changing libraries could be very complicated for brand spanking new (and previous) builders and has determined to begin over. Consequently, it has created Android Jetpack as a method of each offering steerage and in addition as a advisable set of libraries and instruments. Via Jetpack, Google supplies elements that type a beneficial method to architect your app. Moreover, Google hopes that Jetpack will get rid of boilerplate code and simplify complicated duties whereas nonetheless offering backwards compatibility.

To assist tackle model confusion, Google can also be resetting all the Jetpack-related libraries to model and beginning their package deal names with a base identify of androidx. Furthermore, every element might be in its personal library, although it’s necessary to observe that Google continues to be engaged on transitioning libraries to the brand new package deal names.

There are additionally a few different assets in Jetpack, together with the Android KTX library, which makes it simpler to use Kotlin with Android. And, lastly, Android Studio three.2 Canary 14+ now has a Migrate to AndroidX choice to convert your present code and libraries to androidx (however I might advocate you wait till they’re out of alpha, since fairly substantial recognized points exist within the Canary 14 and 15 conversions).

Jetpack is damaged up into 4 fundamental areas: Structure, Basis, Conduct and UI. A lot of the gadgets in Jetpack are a re-arrangement and categorization of present libraries, however a number of of the gadgets are new. By the top of this text, you need to have a great sense of Jetpack’s options and the place to discover extra info on every of them.

Jetpack: Structure

The Structure space of Jetpack consists of eight totally different libraries and instruments that assist you architect your app and handle the info utilized by and displayed within the app. Most of those are present libraries. Nevertheless, there are three new libraries: Navigation, Paging, and WorkManager. Starting with the most recent libraries:


Navigating between actions and/or fragments has by no means been straightforward. Now, with the Navigation library and the navigation viewer constructed into Android Studio, you possibly can visually design how your screens are related to each other. Many individuals have observed that that is comparable to Storyboards in Apple’s Interface Builder for iOS app improvement.

Utilizing Navigation, you visually join one display to one other utilizing “destinations”. You create a navigation graph that may have a beginning vacation spot that may have actions to go to different locations. The wonderful thing about that is you can outline animations within the visible editor. The library even handles deep linking into your app. Passing knowledge between locations could be completed in a protected method with a brand new plugin referred to as safeargs. You possibly can outline what arguments the Fragments within the navigation graph settle for from inside the navigation file itself.

Here’s a screenshot of two fragments with an motion between the 2. You possibly can arrange your app to navigate to the second fragment from inside a button click on listener within the first fragment.


Observe: As of this writing, the Navigation libraries don’t work nicely with the androidx variations of the help libraries. They work sufficiently with the prevailing help libraries however not the brand new ones. Ensure to verify the discharge notes on every model of Android Studio three.2 to see when this has been addressed.

Yow will discover extra details about Navigation right here: Navigation.


Have you ever ever had to cope with giant quantities of associated knowledge? Perhaps an excessive amount of for you to obtain directly? The Paging library will assist by offering methods to deal with the paging of knowledge in a RecyclerView.

The Paging library makes use of a number of key courses: PagedList, PagedListAdapter, and DataSource. PagedList is an inventory that masses knowledge lazily from a DataSource, permitting the app to load knowledge in chunks or pages. PagedListAdapter is a customized RecyclerView.Adapter that handles pages with a DiffUtil callback.

For the DataSource, you’ll use one among three totally different subclasses: PageKeyedDataSource, ItemKeyedDataSource, or PositionalDataSource.

You will discover extra info right here: Paging.


Through the years, there have been a number of methods constructed into Android for dealing with background jobs or alarms. They differ on totally different variations of Android and you’ve got to write lots of code to deal with the totally different variations of the OS.

WorkManager solves this drawback and provides you one library for creating deferrable, asynchronous duties and defining when they need to run. You possibly can outline one-time jobs or repeating jobs.

You will discover extra info right here: WorkManager.

Knowledge Binding

This library has been round for awhile. Knowledge Binding permits you to bind your knowledge to your format in XML, in order that, if you change your knowledge in operating code, the views outlined by the format are routinely up to date. Furthermore, when your UI modifications, your knowledge objects are up to date.

You will discover extra info right here: Knowledge Binding.


The Lifecycle library helps you pay attention for lifecycle occasions in different elements in addition to an actions and fragments. This enables you to have lifecycle-aware logic in locations different than simply an Exercise or Fragment. The library works through the use of annotations on strategies so that you get notified for the occasions that you’re curious about.

You implement LifecycleObserver, annotate strategies and add this observer to a lifecycle proprietor, which is often an Exercise or Fragment. The LifecycleObserver class can get the present lifecycle state by calling lifecycle.getCurrentState() and may use this info to keep away from calling code when not within the right state.

A LifecycleOwner is an object that has Android lifecycle occasions. The help library Exercise and Fragment courses already implement the LifecycleOwner strategies. A LifecycleOwner has a Lifecycle object that it may well return to let the observer know what the present state is.

You’ll find extra info right here: Lifecycles.


The LiveData library makes use of the Observer sample for knowledge however handles it in a lifecycle-aware method. You get the advantages of automated UI updates when knowledge modifications with out calling UI parts when the UI isn’t within the right state.

LiveData is the category that implements the observer sample, holds that knowledge, and notifies listeners when that knowledge has modified.

Yow will discover extra info right here: LiveData.


In case you have ever struggled working with the SQLite database in an Android app, you’ll recognize what the Room library does for you. You create a number of easy courses that outline your knowledge and the way to entry them, and the Room library will do a lot of the relaxation. The one SQL code you have got to write is for queries, that are often fairly simple. And also you achieve compile-time checks of your SQL code when utilizing Room.

There are three necessary courses you want to use with Room: Database (this incorporates your major entry level and holds a reference to the database object for the app), Entity (you create one for every desk within the database), and DAO (this accommodates the strategies for retrieving and managing the info).

You’ll find extra info right here: Room.


Whereas the Room library persists your knowledge in everlasting storage, the ViewModel class permits you to maintain onto knowledge in system reminiscence in a lifecycle-aware method. One of many good options of a ViewModel is that it could survive the re-construction of an Exercise or Fragment over a configuration change resembling a tool rotation. The system will maintain onto that ViewModel re-associate it with the Exercise or Fragment. ViewModels are additionally the place you’ll be able to load knowledge within the background and use LiveData to notify listeners that the info is prepared.

You will discover extra info right here: ViewModel.

Jetpack: Basis

The Basis space of Jetpack includes core system elements, Kotlin extensions and Testing Libraries. This consists of the AppCompat library, which you’ve in all probability been utilizing for awhile, and the brand new Kotlin KTX extension library for simpler improvement in Kotlin.

Testing is essential and has it’s personal part to with frameworks to allow you to check your app, for each UI testing or unit testing.

Android app codebases are getting greater and larger, so that you’ll need to go to the Multidex part of Basis to see how to deal with the 64Okay technique restrict.

You will discover extra details about what’s obtainable in Basis right here: Basis.


The AppCompat library in Jetpack Basis consists of all the elements from the previous v7 libraries. This consists of:

  • AppCompat
  • Cardview
  • GridLayout
  • MediaRouter
  • Palette
  • RecyclerView
  • Renderscript
  • Preferences
  • Leanback
  • Vector Drawable
  • Design
  • Customized tabs
  • And even a couple of others…

You will discover extra info right here: AppCompat.

Android KTX

Android KTX is the one new library in Basis and is a set of Kotlin extensions designed to streamline the event of Android apps when utilizing Kotlin.

There are a number of KTX modules which are linked to different libraries in Jetpack. For example, in case you are working with the Navigation library, then you might use:

  • android.arch.navigation:navigation-common-ktx
  • android.arch.navigation:navigation-fragment-ktx
  • android.arch.navigation:navigation-runtime-ktx
  • and android.arch.navigation:navigation-ui-ktx

SharedPreferences is an instance of how utilizing KTX could make your code easier. Check out the Kotlin code under:

.putBoolean(“key”, worth)

Examine that with the KTX-based code:

putBoolean(“key”, worth)

The KTX code is streamlined a bit and eliminated the necessity to add apply().

And right here’s a SQLite instance with out KTX:

// insert knowledge

And the corresponding KTX model:

// insert knowledge

KTX streamlines a SQLite transaction right into a easy perform name with a trailing lambda.

You’ll find extra info right here: Android KTX.


The Check a part of Basis consists of the Espresso UI testing framework and AndroidJUnitRunner for unit testing. Unit checks are for writing small checks on the logic inside your code, often on the degree of particular person strategies. They need to run quick and provide help to check a selected piece of logic. Espresso is used for the testing of UI parts.

Yow will discover extra info right here: Testing.


As you construct out your app and embrace increasingly libraries, your app can develop giant sufficient that you simply want to use the Multidexing capabilities of Android. As soon as your app consists of greater than 65,536 strategies throughout all courses, you will want to have the system cut up your .dex file (principally, a .zip file of courses) into a number of .dex information.

You possibly can study extra about multidexing and the way to use it right here: Multidex.

Jetpack: Conduct

The Conduct space of Jetpack options libraries that show you how to work together together with your consumer by means of the UI, together with utilizing video or sound. It consists of many elements corresponding to media, notifications, permissions, downloading, sharing and the brand new Slices library.

You’ll find extra info right here: Conduct.


Android Notifications have been round because the starting however have modified over time. They’ve turn into extra expressive and may include buttons and pictures. Since Android Lollipop, a notification referred to as a heads-up notification could be displayed. You possibly can even use notifications on Android Put on and TV for controlling media.

You’ll find extra info right here: Notifications.


This a part of the Conduct space showcases how to use and request permissions. Since Android Marshmallow, permissions at the moment are required to be requested and given earlier than sure parts of a tool’s elements might be accessed, corresponding to contacts, location and digital camera info. You declare permissions within the manifest, and it’s essential to cope with each instances of a consumer accepting or denying your permission request.

You will discover extra info right here: Permissions.


The Sharing a part of Conduct explains how to share content material and the ShareActionProvider class and the way to use it. You’ll can share info with different apps and obtain info from different apps. You’ll be able to create a share motion, share information and use ContentProviders for sharing knowledge.

You will discover extra info right here: Sharing.


The Conduct space of Jetpack consists of the MediaPlayer and AudioManager courses. You’ll be able to play media and sounds, use the MediaPlayer in a service, and management the system quantity. Android helps numerous media codecs. It’s also possible to use the ExoPlayer library, which Google makes use of for it’s personal media gamers in apps similar to YouTube.

You will discover extra info right here: Media.

Obtain Supervisor

The DownloadManager service helps you obtain information within the background. Keep away from coping with connection issues, retrying and even system reboots through the use of the DownloadManager service. Because the DownloadManager is a system service, you’ll be able to simply begin a obtain and pay attention for a broadcast occasion to deal with the completed obtain. No want to fear about community points or crashes.

Yow will discover extra info right here: Obtain Supervisor.


The Slices library is new and allows you to create UI templates to share your knowledge by means of the system in wealthy, versatile layouts. One of many examples Google gave at Google I/O was a climate app that may present extra knowledge relying on the area it has to present. Presently, it is just utilized by the Google Search App however ought to prolong to the Google Assistant.

You can also make your app knowledge obtainable to these apps utilizing Slices so that a consumer can discover info out of your app through the use of Google Search or the Assistant.

You will discover extra info right here: Slices

Jetpack: UI

A lot of the UI libraries in Jetpack are based mostly on present code. They embrace: animations, fragments, palettes, layouts, Emojis, Android Auto, Put on and TV. The EmojiCompat library is the most recent of the libraries and provides you up-to-date emojis and the fonts wanted to use them.

Yow will discover extra details about the UI space right here: UI.


This a part of Jetpack consists of APIs for the several types of animations out there on Android. The Jetpack website documentation covers the previous in addition to new methods to use animations. Vector graphics and vector animations are included as nicely.

There’s additionally a physics-based animation system that features spring and fling animations. You possibly can setup transitions between actions in addition to property and object animations. It’s also possible to set a format to animate any updates you make to the format.

Yow will discover extra info right here: Animations.


EmojiCompat handles emoji characters and makes use of downloadable font help. This enables your app to keep up to date with the newest emojis with out relying on the Android OS. Everytime you replace this library dependency, you’ll have the newest emojis. There’s a concrete Span class referred to as EmojiSpan that’s used to create emojis in your textual content.

You will discover extra info right here: Emoji.


The Fragment help class has moved into this a part of Jetpack. It consists of the totally different sorts of fragments, resembling: DialogFragment, ListFragment, and PreferenceFragmentCompat. An necessary a part of a Fragment is the lifecycle, and the Fragment class included in Jetpack is well-integrated with the Lifecycle class in Jetpack: Structure.

You’ll find extra info right here: Fragments.


A Format defines the Views and ViewGroups in your app. Within the Jetpack Format documentation, you find out how to declare layouts in XML and in code. It additionally describes a number of the extra widespread layouts, comparable to LinearLayout, RelativeLayout and the newer ConstraintLayout. Furthermore, you’ll decide up recommendations on extra particular options like creating lists of things with RecyclerView, in addition to the cardboard format CardView.

You will discover extra info right here: Layouts.


The Palette library permits you to decide colours for themes and from photographs to make your UI’s match your photographs. It’s also possible to create a palette and select totally different colours utilizing the Palette.Builder class. A few of the varieties of colours produced are: Mild Vibrant, Vibrant, Darkish Vibrant, Mild Muted, Muted and Darkish Muted.

You will discover extra info right here: Palettes.


In case you are constructing your app for Android TV, then the TV a part of Jetpack is for you. You’ll be able to management TV Hardware and controllers and create a navigation system that works for TVs. There’s the leanback theme that’s used for TV layouts and the Leanback library helps with TV controls. You’ll be able to setup a D-pad controller to let customers navigate the TV UI.

You will discover extra info right here: TV.

Put on

Put on OS is the model of Android for wearable units. You possibly can create an app that performs media, controls your media from a watch, or create a standalone watch app or watch face.

You will discover extra info right here: Put on.


Jetpack helps you develop apps for Android Auto — audible solely, messaging, working with hardware and extra. You’ll be able to present audio playback for the automotive in addition to messaging. You’ll be able to check Auto apps on the automotive display utilizing the Desktop Head Unit (DHU), which is a testing software that permits you to check with out the hardware.

Yow will discover extra info right here: Auto.

The place to Go From Right here?

As you’ll be able to see, there’s quite a bit included in Google’s new Android Jetpack package deal. All the libraries you understand and love may be discovered there, in addition to a number of new ones.

On this article, you have been launched to the 4 important elements of Jetpack: Structure, Basis, UI and Conduct. A few of the new libraries, just like the Navigation library, will change the best way you write your apps, making it simpler than ever. WorkManager solves an extended standing drawback of reliably operating jobs at totally different occasions on totally different OS variations. Paging will assist with bigger knowledge units and allow you to use RecyclerViews and adapters with much less code. The Android KTX library makes working in Kotlin even simpler and can proceed to evolve. Slices are new and, as you study extra, you need to be in a position to make out there extra of your knowledge outdoors of your app. With the Emoji library, you’ll be able to have all the newest and greatest emojis out there.

Hopefully this publish offered a very good overview of what’s obtainable in Jetpack and can get you enthusiastic about utilizing one thing new. The primary Jetpack web page is situated right here: Android Jetpack

If you need extra in-depth info on Jetpack Navigation, you’ll find a screencast right here. We even have screencasts on LiveData, ViewModel, and Paging Library. Lastly, you’ll find a brief introduction to WorkManager in our Background Processing course right here.

Tell us what a part of Android Jetpack you’re most wanting ahead to utilizing within the dialogue discussion board under!

(perform(d, s, id)
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); = id;
js.src = “//”;
fjs.parentNode.insertBefore(js, fjs);
(doc, ‘script’, ‘facebook-jssdk’));