Android 注销Google帐户时出现空指针异常

已创建Google帐户登录/注销方法。主要思想是当用户点击

“使用谷歌登录”，它将引导用户进入用户配置文件页面，当用户决定登录时，将调用谷歌注销方法并将用户重新引导回主页。但是，问题是，当用户单击注销按钮时，会发生以下错误，发生了什么？请帮忙

我已附上以下代码和错误日志

错误日志：

代码：

//注销：
案例2： //DAPO:DEV02-20141231：交替登录/注销选项，当用户登录时，登录更改为注销，反之亦然

            if (isLogin.equals("Login")){
                //If tab is login, user has not logged in, will navigate user to the login page and allow user to do a Google Login
                Intent intent = new Intent(getApplicationContext(),
                        ChannelAppLoginInfoMainActivity.class);
                startActivity(intent);
            }if (isLogin.equals("Logout")){
                //DAPO:DEV02:20150107:if tab is logout, will navigate user back to home page after user has logged out of Google account.

                Toast.makeText(getApplicationContext(), "Logging out of ChannelApp!", Toast.LENGTH_LONG).show();

                Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
                mGoogleApiClient.disconnect();
                mGoogleApiClient.connect();

                Intent intent= new Intent(getApplicationContext(),
                        ChannelAppMainActivity.class);
                startActivity(intent);
            }
            break;

编辑代码：

//DAPO:DEV02-20150108: Declare Google variable:Google+client
private GoogleApiClient mGoogleApiClient;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
//DAPO:DEV02-20150107: Initialize GoogleApiClient variable
    mGoogleApiClient= new GoogleApiClient.Builder(this).addApi(Plus.API).
            addScope(Plus.SCOPE_PLUS_LOGIN).build();
}
//DAPO:DEV02-20150110: Invoking of GoogleApiClient and connecting GoogleApiClient
@Override
protected void onStart() {
    super.onStart();
    // Connect To Drive and Google+
    mGoogleApiClient.connect();
  }
@Override
protected void onStop(){
    super.onStop();
    // Disconnect from Drive and Google+
    mGoogleApiClient.disconnect();
}

protected void onConnected(Bundle ConnectionHint){
    //All Clients are connected
    Intent intent = new Intent(getApplicationContext(),
            ChannelAppAbstractGetNameTask.class);
    startActivity(intent);
}
//DAPO:DEV02-20150110: End of Edited Version of Invoking of GoogleApiClient and connecting GoogleApiClient

改变它

else{ 
            mPlusClient.clearDefaultAccount();
            mPlusClient.disconnect();
            mPlusClient.connect();
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        } 

---

设法排除故障并发现困扰项目的问题：

首次发行：

GoogleAppClient不断提示建立连接

活动一直将用户导航到没有用户Google凭据的空用户配置文件页面

解决方案：

为GoogleAppClient声明参数（下面列出的代码）

删除

Plus.AccountApi.clearDefaultAccount（mgoogleapClient）

更新代码：

mGoogleApiClient= new GoogleApiClient.Builder(this).addApi(Plus.API).
            addScope(Plus.SCOPE_PLUS_LOGIN).build();

//DAPO:DEV02-20150110: Invoking of GoogleApiClient and connecting GoogleApiClient

@Override
protected void onStart() {
    super.onStart();
    // Connect To Drive and Google+
    mGoogleApiClient.connect();
  }
@Override
protected void onStop(){
    super.onStop();
    // Disconnect from Drive and Google+
    if(mGoogleApiClient.isConnected()){
    mGoogleApiClient.disconnect();
    }
}

protected void onConnected(Bundle ConnectionHint){
    //All Clients are connected
    mSignInClicked=false;
    Toast.makeText(this, "User is connected!", Toast.LENGTH_LONG).show();
}

/* A helper method to resolve the current ConnectionResult error. */
private void resolveSignInError() {
  if (mConnectionResult.hasResolution()) {
    try {
      mIntentInProgress = true;
      startIntentSenderForResult(mConnectionResult.getResolution().getIntentSender(),
          RC_SIGN_IN, null, 0, 0, 0);
    } catch (SendIntentException e) {
      // The intent was canceled before it was sent.  Return to the default
      // state and attempt to connect to get an updated ConnectionResult.
      mIntentInProgress = false;
      mGoogleApiClient.connect();
    }
  }
}
protected void onActivityResult(int requestCode, int responseCode, Intent intent) {
      if (requestCode == RC_SIGN_IN) {
        if (responseCode != RESULT_OK) {
          mSignInClicked = false;
        }

        mIntentInProgress = false;

        if (!mGoogleApiClient.isConnecting()) {
          mGoogleApiClient.connect();
        }
      }
    }
//DAPO:DEV02-20150110: End of Edited Version of Invoking of GoogleApiClient and connecting GoogleApiClient

//Logout:   
        case 2:
            //DAPO:DEV02-20141231: alternation of login/logout options, login to change to logout when user is login and vice versa

            if (isLogin.equals("Login")){
                //If tab is login, user has not logged in, will navigate user to the login page and allow user to do a Google Login
                Intent intent = new Intent(getApplicationContext(),
                        ChannelAppLoginInfoMainActivity.class);
                startActivity(intent);
            }if (isLogin.equals("Logout")){
                //DAPO:DEV02:20150107:if tab is logout, will navigate user back to home page after user has logged out of Google account.

                Toast.makeText(getApplicationContext(), "Logging out of ChannelApp!", Toast.LENGTH_LONG).show();

                //To disconnect user from GoogleApiClient server, remove all Google login credentials.
                mGoogleApiClient.disconnect();
                mGoogleApiClient.connect();

                //Return user to Main HomePage
                startActivity(new Intent(getApplicationContext(), ChannelAppMainActivity.class));
                // make sure the user can not access the page after he/she is logged out
                // clear the activity stack
                finish();
            }
            break;
            //DAPO:DEV02-20141231: End of Edited Version to implement GoogleApiClient logout method and implementation for login/logout method.

---

哪一行是ChannelAppMainActivity.java中的第377行？@Rohit5k2是这一行“mpluClient.clearDefaultAccount（）；”哦……

mpluClient

为空。请发布

ChannelAppMainActivity

activity@Rohit5k2，ChannelAppMainActivity活动的代码是什么？以上代码是ChannelAppMainActivity的一部分。我已经初始化了MPlucClient，但没有查看代码，我无法告诉您为什么为空，这就是为什么我需要完成该活动的代码。您加上客户端对象不知何故变为null。您如何解释此代码？当您未声明意图路径时，意图是什么？您正在重新创建您的活动，以便在注销后重新创建，并使用登录按钮返回同一活动尝试解决方案后仍然存在null指针错误不启动活动检查witout启动活动是否注销？如何初始化MPluClient变量？显然，这是不正确的

else{ 
            mPlusClient.clearDefaultAccount();
            mPlusClient.disconnect();
            mPlusClient.connect();
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        } 

mGoogleApiClient= new GoogleApiClient.Builder(this).addApi(Plus.API).
            addScope(Plus.SCOPE_PLUS_LOGIN).build();

//DAPO:DEV02-20150110: Invoking of GoogleApiClient and connecting GoogleApiClient

@Override
protected void onStart() {
    super.onStart();
    // Connect To Drive and Google+
    mGoogleApiClient.connect();
  }
@Override
protected void onStop(){
    super.onStop();
    // Disconnect from Drive and Google+
    if(mGoogleApiClient.isConnected()){
    mGoogleApiClient.disconnect();
    }
}

protected void onConnected(Bundle ConnectionHint){
    //All Clients are connected
    mSignInClicked=false;
    Toast.makeText(this, "User is connected!", Toast.LENGTH_LONG).show();
}

/* A helper method to resolve the current ConnectionResult error. */
private void resolveSignInError() {
  if (mConnectionResult.hasResolution()) {
    try {
      mIntentInProgress = true;
      startIntentSenderForResult(mConnectionResult.getResolution().getIntentSender(),
          RC_SIGN_IN, null, 0, 0, 0);
    } catch (SendIntentException e) {
      // The intent was canceled before it was sent.  Return to the default
      // state and attempt to connect to get an updated ConnectionResult.
      mIntentInProgress = false;
      mGoogleApiClient.connect();
    }
  }
}
protected void onActivityResult(int requestCode, int responseCode, Intent intent) {
      if (requestCode == RC_SIGN_IN) {
        if (responseCode != RESULT_OK) {
          mSignInClicked = false;
        }

        mIntentInProgress = false;

        if (!mGoogleApiClient.isConnecting()) {
          mGoogleApiClient.connect();
        }
      }
    }
//DAPO:DEV02-20150110: End of Edited Version of Invoking of GoogleApiClient and connecting GoogleApiClient

//Logout:   
        case 2:
            //DAPO:DEV02-20141231: alternation of login/logout options, login to change to logout when user is login and vice versa

            if (isLogin.equals("Login")){
                //If tab is login, user has not logged in, will navigate user to the login page and allow user to do a Google Login
                Intent intent = new Intent(getApplicationContext(),
                        ChannelAppLoginInfoMainActivity.class);
                startActivity(intent);
            }if (isLogin.equals("Logout")){
                //DAPO:DEV02:20150107:if tab is logout, will navigate user back to home page after user has logged out of Google account.

                Toast.makeText(getApplicationContext(), "Logging out of ChannelApp!", Toast.LENGTH_LONG).show();

                //To disconnect user from GoogleApiClient server, remove all Google login credentials.
                mGoogleApiClient.disconnect();
                mGoogleApiClient.connect();

                //Return user to Main HomePage
                startActivity(new Intent(getApplicationContext(), ChannelAppMainActivity.class));
                // make sure the user can not access the page after he/she is logged out
                // clear the activity stack
                finish();
            }
            break;
            //DAPO:DEV02-20141231: End of Edited Version to implement GoogleApiClient logout method and implementation for login/logout method.