Add button to the preference fragment...

add_view_preference_fragment

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        LinearLayout view = (LinearLayout) super.onCreateView(inflater, container, savedInstanceState);

        ZKButton btn_power_off = new ZKButton(getActivity().getApplicationContext());
        btn_power_off.setText(getResources().getString(R.string.power_off_text));

        ZKButton btn_restart = new ZKButton(getActivity().getApplicationContext());
        btn_restart.setText(getResources().getString(R.string.restart_text));

        view.addView(btn_power_off);
        view.addView(btn_restart);

        btn_power_off.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

        btn_restart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

        return view;

  }