After migrating to AndroidX, Error inflating class android.support.design.widget.AppBarLayout

You need to use com.google.android.material.appbar.AppBarLayout.

Version 1.0.0 is already out So you can use implementation 'androidx.appcompat:appcompat:1.0.0'

Add dependency implementation 'com.google.android.material:material:1.0.0'

See Material Component integration for latest release version.
And use

<com.google.android.material.appbar.AppBarLayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content">

</com.google.android.material.appbar.AppBarLayout>

For other artifact and Class Mapping see the AndroidX migration Doc.