TOPIC:

I've tried compiling the PDFSample project in Android Studio 4.1.2 and get the following error:

RadaeePDF-Android-3.54.1\RadaeePDF-Android\PDFSample\ViewLib\src\main\java\com\radaee\annotui\UILStyleButton.java:10: error: package android.support.annotation does not exist
import android.support.annotation.Nullable;

There are a lot of other errors as well, e.g.

RadaeePDF-Android-3.54.1\RadaeePDF-Android\PDFSample\ViewLib\src\main\java\com\radaee\view\PDFViewPager.java:182: error: cannot find symbol
return super.onInterceptTouchEvent(ev);
^
symbol: variable super
location: class PDFViewPager

Could you please help? Thanks!

maybe you are using AndroidX

import android.support.annotation
shall be changed to:
import androidx.annotation.Nullable;

and you can remove PDFViewPager.java and PDFPagerAct.java, if you are not using this class.
this feature can be removed.

Hi,

This is a compatibility issue between Android and AndroidX. It's can be automatically fixed by adding following two flags (or set to true if already exists) in the gradle.properties file in your project:
android.useAndroidX=true
android.enableJetifier=true

Rebuild the project when you have done.