如何在alertDialog中更新按钮颜色变量？

<style name="CustomAlertDialog" parent="Theme.AppCompat.Light.Dialog.Alert">
    <item name="android:buttonBarButtonStyle">@style/CustomButtonBarButton</item>
</style>

<style name="CustomButtonBarButton" parent="Widget.AppCompat.Button.ButtonBar.AlertDialog">
    <item name="android:textColor">@color/custom_button_text_color</item>
    <item name="android:background">@drawable/custom_button_background</item>
</style>

AlertDialog.Builder builder = new AlertDialog.Builder(context, R.style.CustomAlertDialog);
builder.setTitle("Title")
       .setMessage("Message")
       .setPositiveButton("OK", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // 点击按钮后的操作
           }
       })
       .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
               // 点击按钮后的操作
           }
       });

AlertDialog dialog = builder.create();
dialog.show();