Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from AndroidManifest.xml:21:18-91 is also present at AndroidManifest.xml:21:18-86 value=(androidx.core.app.CoreComponentFactory). code example

Example: Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml

With Android Studio 3.2 and higher, you can migrate an existing project to AndroidX by selecting Refactor > Migrate to AndroidX from the menu bar.
The refactor command makes use of two flags. By default, both of them are set to true in your gradle.properties file:
android.useAndroidX=true
The Android plugin uses the appropriate AndroidX library instead of a Support Library.
android.enableJetifier=true
The Android plugin automatically migrates existing third-party libraries to use AndroidX by rewriting their binaries.