使用google plus-android注册

我尝试在我的应用程序中使用google plus添加注册时遇到问题，但出现以下错误：

10-15 16:30:04.697: E/AndroidRuntime(24508): FATAL EXCEPTION: main
10-15 16:30:04.697: E/AndroidRuntime(24508): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=9000, result=0, data=null} to activity {com.mycompany.myapp/com.mycompany.myapp.activities.SignUp}: java.lang.NullPointerException
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread.deliverResults(ActivityThread.java:3000)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread.handleSendResult(ActivityThread.java:3043)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread.access$1100(ActivityThread.java:127)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1188)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.os.Handler.dispatchMessage(Handler.java:99)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.os.Looper.loop(Looper.java:137)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread.main(ActivityThread.java:4441)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at java.lang.reflect.Method.invokeNative(Native Method)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at java.lang.reflect.Method.invoke(Method.java:511)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at dalvik.system.NativeStart.main(Native Method)
10-15 16:30:04.697: E/AndroidRuntime(24508): Caused by: java.lang.NullPointerException
10-15 16:30:04.697: E/AndroidRuntime(24508):    at com.mycompany.myapp.activities.SignUp.onActivityResult(SignUp.java:313)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.Activity.dispatchActivityResult(Activity.java:4649)
10-15 16:30:04.697: E/AndroidRuntime(24508):    at android.app.ActivityThread.deliverResults(ActivityThread.java:2996)
10-15 16:30:04.697: E/AndroidRuntime(24508):    ... 11 more

下面是我的代码：

private static final int REQUEST_CODE_RESOLVE_ERR = 9000;
private ProgressDialog mConnectionProgressDialog;
private PlusClient mPlusClient;
private ConnectionResult mConnectionResult;
private SignInButton signupButtonPlus;

    @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.signup);
            mPlusClient = new PlusClient.Builder(this, this, this)
                    .setVisibleActivities("http://schemas.google.com/AddActivity",
                            "http://schemas.google.com/BuyActivity")
                    .setScopes("PLUS_LOGIN") // Space separated list of scopes
                    .build();
            initWidgets();

        }

在

initwidgets（）

中，我有：

mConnectionProgressDialog = new ProgressDialog(this);
        mConnectionProgressDialog.setMessage("Signing in...");
        signupButtonPlus = (SignInButton) findViewById(R.id.sign_in_button_plus);
        signupButtonPlus.setOnClickListener(this);

还有google plus的其他内容：

@Override
    public void onClick(View v) {
        if (v.getId() == R.id.sign_in_button_plus) {
            Log.v("--", "gplus");
            if (!mPlusClient.isConnected()) {
                mPlusClient.connect();
            }
        }
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode,
            android.content.Intent data) {
        Log.v("--", resultCode+" fb");
        if (requestCode == REQUEST_CODE_RESOLVE_ERR && resultCode == RESULT_OK) {
            mConnectionResult = null;
            mPlusClient.connect();
        } else
            fbLoginManager.loginSuccess(data);
    }



    @Override
    public void onDisconnected() {
        Log.e("gPlus", "disconnected");
    }

    @Override
    public void onConnected(Bundle b) {
        String accountName = mPlusClient.getAccountName();
        Toast.makeText(this, accountName + " is connected.", Toast.LENGTH_LONG)
                .show();
    }

---

fbLoginManager未初始化（代码中的第313行）。根据给定的信息，我只能猜到这些。