Facebook Unity SDK Auto Login not works?

Question

I use unity3D, When I open my game first time on android then Facebook login works fine but when I re-open the game I have to re-login every time. I don't want this, I want it to login itself once I login

Here the code:

public class FaceBook : MonoBehaviour
{

public Text FB_userName;
public Image FB_userDp;

void Start()
{
    FB.Init(InitCallback);
}

void InitCallback()
{
    if (FB.IsInitialized)
    {
        FBLogin();
    }
    else
    {
        Debug.Log("Failed to Initialize the Facebook SDK");
    }
}

void FBLogin()
{
    List<string> perms = new List<string>() { "gaming_user_picture" };
    FB.LogInWithReadPermissions(perms, AuthCallback);
}

void AuthCallback(ILoginResult result)
{
    if (FB.IsLoggedIn)
    {
        FB.API("/me?fields=first_name", HttpMethod.GET, DisplayUsername);
        FB.API("/me/picture?type=med", HttpMethod.GET, DisplayProfilePic);
    }
}

void DisplayUsername(IResult result)
{
    string name = "" + result.ResultDictionary["first_name"];
    FB_userName.text = name;
}

void DisplayProfilePic(IGraphResult result)
{
    FB_userDp.sprite = Sprite.Create(result.Texture, new Rect(0, 0, result.Texture.width, result.Texture.height), new Vector2());
}
}

Answer 1

You just check FB.IsLoggedIn and only prompt the user if they are not logged in