Checking a radiobutton if a specific activity is chosen

Question

In my code, when an activity is opened/started, I am trying to check off one of the radiobuttons in the menu. I have a function in the onCreate method, but I am getting an error saying "int cannot be dereferenced." How do I fix it in this context? Or, is there a completely different way to go about my goal that would work?

onCreate method

    @Override

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_markets);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    R.id.servemenu.setChecked(true);  //this what what I am using to check the radio button

    //home button

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(ActivityMarkets.this, ActivityMenu.class);
            startActivity(intent);
        }
    });

    //Don't know what this is for but I'm not gonna mess with it

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    //Menu I think

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

}

.xml menu code

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<group android:checkableBehavior="single">
    <item
        android:id="@+id/servemenu"
        android:title="Markets We Serve" />
    <item
        android:id="@+id/federalmenu"
        android:title="Federal" />
    <item
        android:id="@+id/statelocalmenu"
        android:title="State and Local" />
    <item
        android:id="@+id/commercialmenu"
        android:title="Commercial" />
</group>

Answer 1

You cannot directly reference the button the way you are doing it.

R.id.servemenu is just an integer which identifies the radiobutton within the view. You must retrieve the radiobutton by using R.id.servemenu, if that is indeed the ID of your RadioButton.

You should do it like this,

RadioButton rb = (RadioButton) findViewById(R.id.servemenu); rb.setChecked(true);