DecorView paddingでDialogがフルスクリーンにならないという問題が発生

AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(), R.style.dialog_bg_theme);
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.dialog_layout, null);
builder.setView(view);

AlertDialog dialog = builder.create();
//    Style    ，               
dialog.setCanceledOnTouchOutside(false);
//   DecorView Padding 0， Dialog     
Window window = dialog.getWindow();
window.setGravity(Gravity.CENTER);
window.getDecorView().setPadding(0, 0, 0, 0);
window.setWindowAnimations(R.style.dialog_animation);
WindowManager.LayoutParams lp = window.getAttributes();
lp.width = WindowManager.LayoutParams.MATCH_PARENT;
lp.height = WindowManager.LayoutParams.WRAP_CONTENT;
window.setAttributes(lp);

return dialog;