ExactCalculator: Convert to Material alert dialogs

import androidx.annotation.Nullable;

import androidx.annotation.StringRes;

import androidx.appcompat.app.AlertDialog;

import androidx.appcompat.app.AppCompatActivity;

import androidx.fragment.app.DialogFragment;

import androidx.fragment.app.FragmentManager;

import com.google.android.material.dialog.MaterialAlertDialogBuilder;

/**

 * Display a message with a dismiss putton, and optionally a second button.

 */

        dialogFragment.show(manager, tag /* tag */);

    }

    public AlertDialogFragment() {

        setStyle(STYLE_NO_TITLE, android.R.attr.alertDialogTheme);

    }

    @Override

    public Dialog onCreateDialog(Bundle savedInstanceState) {

        final Bundle args = getArguments() == null ? Bundle.EMPTY : getArguments();

        final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        final MaterialAlertDialogBuilder builder = new MaterialAlertDialogBuilder(getActivity());

        final LayoutInflater inflater = LayoutInflater.from(builder.getContext());

        final TextView messageView = (TextView) inflater.inflate(