Android Studio AlertDialog Customize 5

MyDialogFragment.java

public class MyDialogFragment extends DialogFragment {

    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {

        TextView titleView = new TextView(getActivity());
        titleView.setText("タイトル");
        titleView.setTextSize(24);
        titleView.setTextColor(Color.WHITE);
        titleView.setBackgroundColor(getResources().getColor(R.color.alertBlue));
        titleView.setPadding(20, 20, 20, 20);
        titleView.setGravity(Gravity.CENTER);

        TextView msgView = new TextView(getActivity());
        msgView.setText("ここにメッセージを入力します。ここにメッセージを入力します。ここにメッセージを入力します。");
        msgView.setTextSize(16);
        msgView.setTextColor(Color.BLACK);
        msgView.setPadding(20, 20, 20, 40);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setCustomTitle(titleView)
                .setView(msgView)
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // このボタンを押した時の処理を書きます。
                    }
                });
        return builder.create();
    }

    @Override
    public void onStart() {
        super.onStart();
        AlertDialog alertDialog = (AlertDialog) getDialog();
        if (alertDialog != null) {
            alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setTextColor(Color.WHITE);
            alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setBackgroundColor(getResources().getColor(R.color.alertBlue));
        }
    }
}