Question

我的主要活动中有一个方法，如果用户登录，则允许用户注销，如果用户注销，则登录。但是当我调用facebook sdk的.logout（）方法时，应用程序崩溃了。我的代码出现错误 Logcat在fb.logout（MainActivity.this）返回NULLPOINTEREXCEPTION错误;

public void loginFacebook(View v) {
    // TODO Auto-generated method stub
    new Thread(new Runnable() {

        @Override
        public void run() {

            // log out if logged in
            if (fb.isSessionValid()) {
                try {
                    updateButtonImage();
                    Log.d("Session Valid", "Session Valid");
                    fb.logout(MainActivity.this);
                    if (fb.isSessionValid())
                        Log.d("Session Valid", "Session Valid");
                    else
                        Log.d("Session Not Valid", "Session Not Valid");

                } catch (MalformedURLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

            else {
                // log in if logged out
                Log.d("Session Not Valid", "Session Not Valid");
                // login
                runOnUiThread(new Runnable() {
                    public void run() {
                        fb.authorize(MainActivity.this,
                                new DialogListener() {

                                    // I have deleted this part as this is not relevant to this question
                                });

                    }
                });

            }
        }

    }).start();

}

logcat的：

    03-08 16:11:22.242: E/AndroidRuntime(11956): FATAL EXCEPTION: Thread-14
03-08 16:11:22.242: E/AndroidRuntime(11956): java.lang.NullPointerException
03-08 16:11:22.242: E/AndroidRuntime(11956):    at android.webkit.CookieSyncManager.createInstance(CookieSyncManager.java:96)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.facebook.internal.Utility.clearCookiesForDomain(Utility.java:554)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.facebook.internal.Utility.clearFacebookCookies(Utility.java:578)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.facebook.Session.closeAndClearTokenInformation(Session.java:798)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.facebook.android.Facebook.logoutImpl(Facebook.java:669)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.facebook.android.Facebook.logout(Facebook.java:646)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at com.appquest.awaaziitkgp.MainActivity$4.run(MainActivity.java:167)
03-08 16:11:22.242: E/AndroidRuntime(11956):    at java.lang.Thread.run(Thread.java:1019)

Answer 1

出于某种原因，Facebook对象fb在null方法中变为run()。您可以尝试拨打

session.closeAndClearTokenInformation();

相反，它做同样的事情。或者，您可以尝试找出fb成为null的原因。我怀疑它与你在另一个Thread上运行它的事实有关（我真的不需要这样做）。

应用程序在facebook logout，NullPointerException崩溃

1 个答案: