Hiding and showing a single Menu Button

I have a project for an Android class, so I'm still learning and this should be a basic question. We were given a tip calculator and already made some modifications, now we have to add a menu.

When it starts up, it will be in multi-person mode. Gives a text box and Text Field for how many people you want the bill split into. When you hit menu, it should show a Single person mode which eliminates a text box and text field. The menu then changes to show a multi-person mode button in the menu.

I've got everything to work except it's showing both buttons, I cannot figure out how to hide a button temporarily. The main error is:

Cannot invoke setVisibility(int) on the primitive type int

on the statement:

multiple_button.setVisibility(View.GONE);

I've tried every combination of hiding the button I can think of, and think that the above line is correct, but unsure of how make it work.

one_person_button = View.VISIBLE;
    multiple_button = View.GONE;

I have this in the code, but it's not doing anything either.

Any help would be greatly appreciated.

edit: code. I've read through the link, but considering I don't have a OnPrepareOptions section, I need to re-read it

package com.android;


import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.TextView;
import android.widget.Button;
import android.view.Menu;
import开发者_如何学编程 android.view.MenuItem;
import android.view.View;

public class tipcalc extends Activity
{

    public static int one_person_button = Menu.FIRST;
    private int multiple_button = Menu.FIRST +1;
    static final private int reset_button = Menu.FIRST +2;
    private static final int MENU_ITEM = 0;

    private EditText txtbillamount;
    private EditText txtpeople;
    private EditText txtpercentage;

    private TextView txtperperson;
    private TextView txttipamount;
    private TextView txttotal;

    private Button btncalculate;
    private Button btnreset;

    private double billamount = 0;
    private double percentage = 0;
    private double numofpeople=0; 
    private double tipamount = 0;
    private double totaltopay = 0;
    private double perperson = 0;
    private View view; 


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        initControls();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        MenuItem itemOne = menu.add(0, one_person_button, Menu.NONE,
                R.string.one_person);
        MenuItem itemMultiple = menu.add(1, multiple_button, Menu.NONE,
                R.string.multiple);



        MenuItem itemReset = menu.add(2, reset_button, Menu.NONE,
                                    R.string.reset);

        itemOne.setIcon(R.drawable.ic_menu_invite);
        itemMultiple.setIcon(R.drawable.ic_menu_allfriends);
        itemReset.setIcon(R.drawable.ic_menu_refresh);

        one_person_button.setGroupVisible(0, true);
        multiple_button.setVisibility(View.GONE);
        one_person_button = View.VISIBLE;
        multiple_button = View.GONE;

        return true;
    }


    public boolean onOptionsItemSelected(MenuItem item) {
        super.onOptionsItemSelected(item);
        if (one_person_button == View.VISIBLE) {
             ((TextView)findViewById(R.id.txtpeople)).setVisibility(View.INVISIBLE) ;
             ((TextView)findViewById(R.id.widget30)).setVisibility(View.INVISIBLE) ;
             multiple_button = View.VISIBLE;
             one_person_button = View.GONE;
             numofpeople = 1; }
        else if (multiple_button == View.VISIBLE) {
             ((TextView)findViewById(R.id.txtpeople)).setVisibility(View.VISIBLE) ;
             ((TextView)findViewById(R.id.widget30)).setVisibility(View.VISIBLE) ;
             multiple_button = View.GONE;
             one_person_button = View.VISIBLE;
        }
        return false;
    }

    private void initControls()
    {
        txtbillamount = (EditText)findViewById(R.id.txtbillamount);
        txtpeople = (EditText)findViewById(R.id.txtpeople);
        txtperperson=(TextView)findViewById(R.id.txtperperson);
        txttipamount=(TextView)findViewById(R.id.txttipamount);
        txttotal=(TextView)findViewById(R.id.txttotal);

        btncalculate = (Button)findViewById(R.id.btncalculate);
        btnreset = (Button)findViewById(R.id.btnreset);

        btncalculate.setOnClickListener(new Button.OnClickListener() { public void onClick (View v){ calculate(); }});
        btnreset.setOnClickListener(new Button.OnClickListener() { public void onClick (View v){ reset(); }});

    }

    private void calculate()
    {
    billamount=Double.parseDouble(txtbillamount.getText().toString()); 
    numofpeople=Double.parseDouble(txtpeople.getText().toString());    



        RadioButton poorButton = (RadioButton) findViewById(R.id.radioButton1);
        RadioButton goodButton = (RadioButton) findViewById(R.id.radioButton2);
        RadioButton excellentButton = (RadioButton) findViewById(R.id.radioButton3);

    if (poorButton.isChecked()){
       percentage = Double.parseDouble(poorButton.getText().toString());
    } else if (goodButton.isChecked()){
        percentage = Double.parseDouble(goodButton.getText().toString());
    } else if (excellentButton.isChecked()){
        percentage = Double.parseDouble(excellentButton.getText().toString());
    }




    tipamount=(billamount*percentage)/100;
    totaltopay=billamount+tipamount;
    perperson=totaltopay/numofpeople;

    txttipamount.setText(Double.toString(tipamount));
    txttotal.setText(Double.toString(totaltopay));
    txtperperson.setText(Double.toString(perperson));        
    }

    private void reset()
    {
    txtbillamount.setText("");
    txtpeople.setText("");

    txtperperson.setText("");
    txttipamount.setText("");
    txttotal.setText("");
    }
}

Post all of your relavent source code. Without it, we cannot give you specific advice about what is going wrong.

I can tell you though you'll be needing to override onPrepareOptionsMenu() and inside there you'll want to check which mode your in and make the proper button be visible. But you need to call setVisibility(View.VISIBLE); on a reference to the button widget, not on an int.

This page holds the answer to your questions.

try calling setVisibility with 8