无法使用Facebook SDK登录

Question

In my app, I am trying to implement Facebook login. I have an IntroLogin Activity after splash to determine whether the user is already logged in or not. If the user is already logged in, it straight loads MainActivity. Otherwise, it asks the user to log in.

My method to determine if the user is logged in or not works well in Android 6+. However, in Android Lollipop, after user sign-in (user get's to give app authenticate to use there info in popup), the app closes. I get no FCs or any messages in log. It just closes. Even if the user restarts the app, it again prompts to login.

My IntroLogin Activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_intro_login);

    sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

    loginButton = (Button) findViewById(R.id.login_button);

    FacebookSdk.sdkInitialize(getApplicationContext());
    callbackManager = CallbackManager.Factory.create();

    AccessToken accessToken = AccessToken.getCurrentAccessToken();
    if(accessToken != null){
        finish();
    }
    else{
        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                PopupLogin();
            }
        });
    }
}

public void PopupLogin() {
    // Set permissions
    LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile"));
    LoginManager.getInstance().setLoginBehavior(LoginBehavior.WEB_VIEW_ONLY).registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            Log.i(TAG, "onSuccess: " + loginResult);
            startActivity(new Intent(IntroLogin.this, MainActivity.class));
            finish();
        }

        @Override
        public void onCancel() {
            Log.d("MyApp", "Login canceled");
            Snackbar snackbar = Snackbar.make(loginButton, "Login process canceled", Snackbar.LENGTH_INDEFINITE);
            snackbar.getView().setBackgroundColor(ContextCompat.getColor(IntroLogin.this, R.color.colorPrimaryDark));
            snackbar.setActionTextColor(ContextCompat.getColor(IntroLogin.this, R.color.pure_white));
            snackbar.setAction(R.string.retry_login, new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    loginButton.performClick();
                }
            });
            snackbar.show();
        }

        @Override
        public void onError(FacebookException error) {
            Log.d("Myapp", error.toString());
            Toast.makeText(IntroLogin.this, error.getMessage(), Toast.LENGTH_LONG).show();
        }
    });
}

UPDATE:

I found the cause but not the solution, I think OnActivityResult is not getting called in lollipop, that maybe the reason i am not seeing any log.

Answer 1

you should initialize your facebooksdk just after calling super.oncreate()

And also you are calling finish() when accessToken != null which means when user is already logged in facebook it will close the activity..

Change your onCreate() method code to:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FacebookSdk.sdkInitialize(getApplicationContext());
        setContentView(R.layout.activity_intro_login);
        callbackManager = CallbackManager.Factory.create();
        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

         loginButton = (Button) findViewById(R.id.login_button);
         updateWithToken(AccessToken.getCurrentAccessToken());
        accessTokenTracker = new AccessTokenTracker() {
            @Override
            protected void onCurrentAccessTokenChanged(AccessToken oldToken, AccessToken newToken) {
                updateWithToken(newToken);
            }
        };
        accessTokenTracker.startTracking();
    }

private void updateWithToken(AccessToken currentAccessToken) {

        if (currentAccessToken != null) {
            Log.d("FB", "User Logged IN.");
            //programetically logout user or do your on success
            LoginManager.getInstance().logOut();
        } else {
            Log.d("FB", "User Logged Out.");
            loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                PopupLogin();
            }
        });
      }
  }

Answer 2

Found out the cause. I have added android:launchMode="singleTop" in my loginActivity, that was the reason why OnActivityResult was not calling.