اموزش کار با کتابخونه material dialog در بیسیک فور اندروید

سلام با این ارور مواجه شدم:

B4A Version: 9.80
Java Version: 8
Parsing code. (0.01s)
Building folders structure. (0.03s)
Compiling code. (0.02s)
Compiling layouts code. (0.00s)
Organizing libraries. (0.00s)
(AndroidX SDK)
Generating R file. (0.00s)
Compiling generated Java code. Error
javac 1.8.0_162
src\de\amberhome\materialdialogs\example\main.java:17: error: cannot access RecyclerView
public class main extends de.amberhome.materialdialogs.MaterialDialogsActivity implements B4AActivity{
^
class file for android.support.v7.widget.RecyclerView not found
Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output
۱ error