Did not succeed yet to run the Ham Menu

I'm a learner and I seek your help. I want to add this button into a project.

I wrote the following code in my activity_main.xml

<com.nightonke.boommenu.BoomMenuButton
        android:id="@+id/bmb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:bmb_buttonEnum="ham"
        app:bmb_buttonPlaceEnum="buttonPlace_ham_4"
        app:bmb_piecePlaceEnum="piecePlace_ham_4"
        />

I created a java file Nn.java

package myappname.name;

import android.os.Bundle;
import android.view.View;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;



import com.nightonke.boommenu.BoomButtons.ButtonPlaceEnum;
import com.nightonke.boommenu.BoomButtons.HamButton;
import com.nightonke.boommenu.BoomMenuButton;
import com.nightonke.boommenu.ButtonEnum;
import com.nightonke.boommenu.Piece.PiecePlaceEnum;



public class Nn extends AppCompatActivity {


    private BoomMenuButton bmb;

    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bmb = (BoomMenuButton) findViewById(R.id.bmb);
        bmb.setButtonEnum(ButtonEnum.Ham);
        bmb.setPiecePlaceEnum(PiecePlaceEnum.HAM_4);
        bmb.setButtonPlaceEnum(ButtonPlaceEnum.HAM_4);
        bmb.addBuilder(getHamButtonBuilder());
        bmb.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                for (int i = 0; i < bmb.getPiecePlaceEnum().pieceNumber(); i++) {
                    HamButton.Builder builder = new HamButton.Builder()
                            .normalImageRes(R.drawable.butterfly)
                            .normalTextRes("Butter Doesn't fly!")
                            .subNormalTextRes("Little butter Doesn't fly, either!");
                    bmb.addBuilder(builder);
                }
            }
        });



    }

    ;


    static HamButton.Builder getHamButtonBuilder() {
        return new HamButton.Builder()
                .normalImageRes(getImageResource())
                .normalTextRes(R.string.text_ham_button_text_normal)
                .subNormalTextRes(R.string.text_ham_button_sub_text_normal);
    }

    private static int[] imageResources = new int[]{
            R.drawable.bat,
            R.drawable.bear,
            R.drawable.bee,
            R.drawable.butterfly,
    };

    private static int imageResourceIndex = 0;

    static int getImageResource() {
        if (imageResourceIndex >= imageResources.length) imageResourceIndex = 0;
        return imageResources[imageResourceIndex++];
    }

}

Whenever I click the Menu button, I close the app. Would someone help me please. I one four buttons, to of them redirect to external links