The name `FB' does not exist in the current context

Question

I am trying to allow the user to share the final game score on their FaceBook timeline. I am following FaceBook tutorial and examples. When I try to download and import the FaceBook SDK package (7.11-2.0) in Unity (2017.3) I get the error:

error CD1704: An assembly with the same name 'FaceBook.Unity.Settings' has already been imported. Consider removing one of the references or sign the assembly Library/FacebookSDK/FaceBook.Unity.Settings.dll (Location of the symbol related to previous error)

I read on other posts that the latest version of Unity may have the Facebook SDK already integrated, and will not require importing the package manually.

I therefore removed the from my project. The error disappear, but when I try to initialize the Facebook SDK for Unity using the code below, I get the error:

The name `FB' does not exist in the current context

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using Facebook.Unity;

public class ShareOnFaceBook : MonoBehaviour {

    // Use this for initialization
    void Awake () {

    if (!FB.IsInitialized) {
        // Initialize the Facebook SDK
        FB.Init(InitCallback, OnHideUnity);
    } else {
        // Already initialized, signal an app activation App Event
        FB.ActivateApp();
    }
}

Answer 1

Assuming you are following this: https://developers.facebook.com/docs/unity/examples

Unity 2017.1.0f3 without the Facebook SDK installed leads to this error:

Error CS0246: The type or namespace name 'Facebook' could not be found (are you missing a using directive or an assembly reference?) (CS0246) (Assembly-CSharp)

Once Facebook SDK is installed, the script works (as long as you include all of the code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using Facebook.Unity;

public class ShareOnFaceBook : MonoBehaviour {

    // Use this for initialization
    void Awake () {

        if (!FB.IsInitialized) {
            // Initialize the Facebook SDK
            FB.Init(InitCallback, OnHideUnity);
        } else {
            // Already initialized, signal an app activation App Event
            FB.ActivateApp();
        }
}private void InitCallback ()
{
    if (FB.IsInitialized) {
        // Signal an app activation App Event
        FB.ActivateApp();
        // Continue with Facebook SDK
        // ...
    } else {
        Debug.Log("Failed to Initialize the Facebook SDK");
    }
}

private void OnHideUnity (bool isGameShown)
{
    if (!isGameShown) {
        // Pause the game - we will need to hide
        Time.timeScale = 0;
    } else {
        // Resume the game - we're getting focus again
        Time.timeScale = 1;
        }
    }
}

I can't find proof that FB SDK is included with newer Unity versions. Perhaps it is offered in the installer.

I speculate that your Unity or C# environment (MonoDevelop) is bugging out and might be "fixed" by a restart. Alternatively it could be that you only partially removed the FB SDK or have various versions of it conflicting with itself.

Also: perhaps your "FB"-related error refers to another script.

To verify, start a new project, import the FB SDK .unitypackage and try out above C# script. It should work.