Transparent ProgressDialog with ProgressBar

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:context="net.pupli.lastlab.PupliProgressDialogFragment">

    <android.support.constraint.Guideline
        android:id="@+id/guideline12"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.5" />

    <me.zhanghai.android.materialprogressbar.MaterialProgressBar
        android:id="@+id/progressbarMain"
        style="@style/Widget.MaterialProgressBar.ProgressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:indeterminate="true"
        app:layout_constraintEnd_toEndOf="@id/guideline12"
        app:layout_constraintStart_toStartOf="@id/guideline12"
        app:mpb_progressStyle="circular" />

</android.support.constraint.ConstraintLayout>

public class PupliProgressDialogFragment extends DialogFragment {

    MaterialProgressBar progressbarMain;

    public PupliProgressDialogFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_pupli_progress_dialog, container, false);

        // make dialogFragment transparent
        getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

        // remove title of dialog fragment
        getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);

        // set dialogFragment non cancelable, so users can not dismiss progressbar from screen
        this.setCancelable(false);

        progressbarMain = view.findViewById(R.id.progressbarMain);

        return view;
    }

    @Override
    public void onResume() {
        super.onResume();

        // set width and hight of dialogFragment
        getDialog().getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
    }
}