Question

我在android中开发应用程序。在那里，我使用SharedPreferences进行会话管理的登录和注销活动。我的应用程序注销，将数据存储在sharedpreferences中以保持会话成功完成。当我从应用程序注销（第二个活动）并获得渲染到第一个活动（登录活动）但发生的事情是当我成功注销后再点击模拟器上的按钮仍然再次呈现给第二个活动和某些版本如2.3.3等遇到例外

java.lang.RuntimeException: Unable to destroy activity {com.oj.bs/com.oj.bs.LoginActivity}: java.lang.NullPointerException

任何人都可以解决问题。请参考以下代码

以下是登录活动代码

sessionmngr = new SessionManager(getApplicationContext());

                    JSONObject json_user = jsonObj.getJSONObject("user");
                    sessionmngr.createLoginSession(id,json_user.getString(KEY_UNAME), 
                            json_user.getString(KEY_UEMAIL));
                     .
                     .

以下是会话管理

public class SessionManager {

SharedPreferences pref;
Editor editor;
Context contxt;
//shared pref mode
int PRIVATE_MODE = 0;
 // Sharedpref file name
private static final String PREF_NAME = "bookingScapePref";

// All Shared Preferences Keys
private static final String IS_LOGIN = "IsLoggedIn";
public static final String KEY_NAME = "name";
public static final String KEY_ID = "id";
public static final String KEY_EMAIL = "email";

public SessionManager(Context context) {
    super();
    this.contxt = context;
    pref = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = pref.edit();
    editor.commit();
}
/**
 * Create login session
 * */
public void createLoginSession(int id,String name, String email) {

    editor.putBoolean(IS_LOGIN,true);
    editor.putString(KEY_NAME, name);
    editor.putString(KEY_EMAIL, email);
    editor.putInt(KEY_ID, id);
    editor.commit();
}
/**
 * Get stored session data
 * */
public HashMap<String, String> getUserDetails() {
    HashMap<String, String> userDetails = new HashMap<String, String>();
    userDetails.put(KEY_NAME, pref.getString(KEY_NAME, null));
    userDetails.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));
    return userDetails;
}
/**
 * Check login method will check user login status
 * */
public void checkLogin() {

    if (!this.isLoggedIn()) {
        Intent i = new Intent(contxt, LoginActivity.class);
        //closing all the activity
        i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        //Add new Flag to start new Activity
        i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        contxt.startActivity(i);
    }
}

public void logoutUser() {
    //clearing all data from sharedPreferences
    editor.clear();
    editor.commit();
    Intent intnt = new Intent(contxt, LoginActivity.class);
    // Closing all the Activities
    intnt.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    // Add new Flag to start new Activity
    intnt.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

    // Staring Login Activity
    contxt.startActivity(intnt);
}

/**
 * Quick check for login
 * **/
// Get Login State
public boolean isLoggedIn(){
    return pref.getBoolean(IS_LOGIN, false);
}

}

这是第二项活动，我正在检查会话

public class ProjectFragActivity extends SherlockFragmentActivity {

SessionManager sessionMngr ;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    sessionMngr = new SessionManager(getApplicationContext());

    Toast.makeText(getApplicationContext(), "User Login Status: " + sessionMngr .isLoggedIn(), 
            Toast.LENGTH_LONG).show();
    sessionMngr.checkLogin();
            .
            .

Answer 1

我不知道这个会话和所有的工作是如何工作的，bt，你在执行注销操作时尝试使用finish（）函数，这样当按下后退按钮时动作不会出现

注销后，第二个活动仍然在会话中

1 个答案: