Duplicate class android.support.v4.app.INotificationSideChannel found in modules classes?

Question

I am developing a news app but I am getting following errors in from gradle console

(androidx.core:core:1.0.1) and classes.jar (com.android.support:support-c         


        

Answer 1

Adding these lines to gradle.properties file solves "Duplicate Class" errors:

android.useAndroidX=true

android.enableJetifier=true

However, this generated new errors in my project:

"package android.support.annotation does not exist"

"cannot find symbol class Fragment"

"package android.support.v4.content does not exist"

"Program type already present"

etc.

However, the refactoring worked for me:

Migrate your project to AndroidX by selecting Refactor > 
"Migrate to AndroidX" from the menu bar.

Select Build > Clean project

Restore Android Studio

Now, my project (Match4app) works with AndroidX and I was able to publish it in the PlayStore without any issues.

Comment: This task also allowed me to upgrade all other libraries that depend on AndroidX (i.e. com.firebaseui:firebase-ui-auth:6.0.2, com.google.android.gms:play-services-games:18.0.1, com.google.android.gms:play-services-auth:17.0.0, com.google.android.gms:play-services-ads:18.2.0, etc.).