Android : Running a public void via a String [duplicate]

This question already has an answer here:

• Cannot Make Static Reference to Non-Static Method 6 answers

I have a function that's saving a string, and I want that this function will run another one. this is my code:

public static String IsLoggedIn() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            String cookies = CookieManager.getInstance().getCookie(getUrl);
            BasicCookieStore lCS = getCookieStore(cookies, "klh-dev.com");
            HttpContext localContext = new BasicHttpContext();
            DefaultHttpClient httpclient = new DefaultHttpClient();
            httpclient.setCookieStore(lCS);
            localContext.setAttribute(ClientContext.COOKIE_STORE, lCS);

            HttpGet get = new HttpGet("http://klh-dev.com/lehava/lehava/system/isloggedin.php");

            try {
                result=httpclient.execute(get,localContext);
                response_str = EntityUtils.toString(result.getEntity());
                System.out.println(response_str);
                UpdateMenu(); //This is the line I'm trying to add
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }).start();
    return response_str;
}
public void UpdateMenu() {

    mTitle = mDrawerTitle = getTitle();
    mPlanetTitles = getResources().getStringArray(R.array.planets_array);
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.left_drawer);

    if (isUserLoggedIn.equals("0")) {
        Arrays.copyOfRange(mPlanetTitles, 0, 2);
    }

    mDrawerList.setAdapter(new ArrayAdapter<String>(this,
            R.layout.drawer_list_item, mPlanetTitles));

}

In the try I'm trying to add UpdateMenu(); but it's not working. The error is: Cannot make a static reference to the non-static method UpdateMenu() from the type MainActivity

Thank you for helping!