为什么我的Facebook与Android应用程序集成会崩溃？

我是安卓系统的新手。我已经将Facebook集成到Android中。该应用程序工作正常，但在出现以下错误后崩溃。我的Facebook集成代码如下：

Login.class

public class Login extends Activity {
private static final String URL_PREFIX_FRIENDS = "https://graph.facebook.com/me/friends?access_token=";
private ImageButton buttonLoginLogout;
public static final String PREFS_PRIVATE = "PREFS_PRIVATE";
private Button b;

private Session.StatusCallback statusCallback = new SessionStatusCallback();
Databasehandler db=new Databasehandler(this);
HashMap<String, String>map=new HashMap<String, String>();
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.login);
    buttonLoginLogout = (ImageButton)findViewById(R.id.imageButton1);



    Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);

    Session session = Session.getActiveSession();
    if (session == null) {
        if (savedInstanceState != null) {
            session = Session.restoreSession(this, null, statusCallback, savedInstanceState);
        }
        if (session == null) {
            session = new Session(this);
        }
        Session.setActiveSession(session);
        if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {
            session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
        }
    }

    updateView();
}

@Override
public void onStart() {
    super.onStart();
    Session.getActiveSession().addCallback(statusCallback);
}

@Override
public void onStop() {
    super.onStop();
    Session.getActiveSession().removeCallback(statusCallback);
}



@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
}

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    Session session = Session.getActiveSession();
    Session.saveSession(session, outState);
}
@Override
protected void onDestroy() {

    super.onDestroy();

}
private void updateView() {
    Session session = Session.getActiveSession();
    if (session.isOpened()) {
        Request.executeMeRequestAsync(session,new Request.GraphUserCallback() {

            @Override
            public void onCompleted(GraphUser user, Response response) {
                // TODO Auto-generated method stub
                final String t1=user.getId();
                final String t2=user.getName();
                 // SharedPreferences myPrefs =getSharedPreferences("myprefs",MODE_WORLD_READABLE);
                int count=db.getme();
                if(count==0)
                {
                map.put("uid",t1.toString());
                map.put("name",t2.toString());
                db.insertnewuser(map);
                }
   }
        });

     Intent ik=new Intent(Login.this,MainActivity.class);

        ik.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
        startActivity(ik);
         } else {

        buttonLoginLogout.setOnClickListener(new OnClickListener() {
            public void onClick(View view) { onClickLogin(); }
        });
    }
}

private void onClickLogin() {
    Session session = Session.getActiveSession();
    if (!session.isOpened() && !session.isClosed()) {
        session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
    } else {
        Session.openActiveSession(this, true, statusCallback);
    }
}
 private class SessionStatusCallback implements Session.StatusCallback {
    @Override
    public void call(Session session, SessionState state, Exception exception) {
        updateView();
    }
}
}

---

由于某种原因，

onCompleted

回调中

user

变量的值为

null

。如果你看一下，上面写着：

user    The GraphObject representing the returned user, or null

---

因此，您应该始终检查

user

是否为

null

。我不熟悉Facebook SDK，所以我不能说为什么它可以是空的，但是我想你可以从同样的方法提供的

响应
对象中得到关于错误的有用信息。
登录名是什么。java:355
？最终字符串t1=user.getId（）；
user    The GraphObject representing the returned user, or null