ClassNotFoundException: Didn't find class "android.support.v4.content.FileProvider" after androidx migration

Thanks to @CommonsWare

More explanation:

What to do, find the android.support.v4.FileProvider in your <provider> in AndroidManifest.xml.

Change it to androidx.core.content.FileProvider

In manifiest.xml file simply change this

<provider
        android:name="android.support.v4.content.FileProvider"
      .....
</provider>

To this one

<provider
    android:name="androidx.core.content.FileProvider"
    ......
</provider>

Or Simply

• Go to Refactor (Studio -> Menu -> Refactor)
• Click the Migrate to AndroidX.
• it's working.

why does it want to load the old version of FileProvider?

Based on the stack trace, perhaps you are still using the old package name in the <provider> element in the manifest.