android - What is AndroidX?

Question

I am reading about a room library of Android. I see they changed package android to androidx. I did not understand that. Can someone explain, please?

implementation "androidx.room:room-runtime:$room_version"
annotationProcessor "androidx.room:room-compiler:$room_version"

Even this is available with the android package also.

implementation "android.arch.persistence.room:runtime:$room_version"
annotationProcessor "android.arch.persistence.room:compiler:$room_version"

• What was in need of packaging new support libraries in androidx instead of android?
• Use case and affect factors in existing projects.

Answer 1

AndroidX - Android Extension Library

From AndroidX documentation

We are rolling out a new package structure to make it clearer which packages are bundled with the Android operating system, and which are packaged with your app's APK. Going forward, the android.* package hierarchy will be reserved for Android packages that ship with the operating system. Other packages will be issued in the new androidx.* package hierarchy as part of the AndroidX library.

Need of AndroidX

AndroidX is a redesigned library to make package names more clear. So from now on android hierarchy will be for only android default classes, which comes with android operating system and other library/dependencies will be part of androidx (makes more sense). So from now on all the new development will be updated in androidx.

com.android.support.** : androidx.
com.android.support:appcompat-v7 : androidx.appcompat:appcompat com.android.support:recyclerview-v7 : androidx.recyclerview:recyclerview com.android.support:design : com.google.android.material:material

Complete Artifact mappings for AndroidX packages

AndroidX uses Semantic-version

Previously, support library used the SDK version but AndroidX uses the Semantic-version. It’s going to re-version from 28.0.0 → 1.0.0.

How to migrate current project

In Android Studio 3.2 (September 2018), there is a direct option to migrate existing project to AndroidX. This refactor all packages automatically.

Before you migrate, it is strongly recommended to backup your project.

Existing project

• Android Studio > Refactor Menu > Migrate to AndroidX...
• It will analyze and will open Refractor window in bottom. Accept changes to be done.

New project

Put these flags in your gradle.properties

android.enableJetifier=true
android.useAndroidX=true

Check @Library mappings for equal AndroidX package.

Check @Official page of Migrate to AndroidX

What is Jetifier?

Bugs of migrating

• If you build app, and find some errors after migrating, then you need to fix those minor errors. You will not get stuck there, because that can be easily fixed.
• 3rd party libraries are not converted to AndroidX in directory, but they get converted at run time by Jetifier, so don't worry about compile time errors, your app will run perfectly.

Support 28.0.0 is last release?

From Android Support Revision 28.0.0

This will be the last feature release under the android.support packaging, and developers are encouraged to migrate to AndroidX 1.0.0

So go with AndroidX, because Android will update only androidx package from now.

Further Reading

https://developer.android.com/topic/libraries/support-library/androidx-overview

https://android-developers.googleblog.com/2018/05/hello-world-androidx.html