Android: sharedPreference片段，而不是从类读取数据

Question

我为SharedPref工作准备了这门课

package com.box.a100rados.Data;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;

import static android.content.Context.MODE_PRIVATE;


public class UserAccessSession {

    private SharedPreferences sharedPref;
    private Editor editor;


    private static final String FILTER_RADIUS_DISTANCE      = "FILTER_RADIUS_DISTANCE";
    private static final String Name = "Name";
    private static final String Photo = "Photo";
    private static final String Rank = "Rank";
    private static final String Sid = "Sid";
    private static final String Ban = "Ban";
    private static final String Latitude = "Latitude";
    private static final String Longitude = "Longitude";

    private static final String SHARED = "UserData";
    private static UserAccessSession instance;

    public static UserAccessSession getInstance(Context context) {
        if(instance == null)
            instance = new UserAccessSession(context);
        return instance;
    }

    public UserAccessSession(Context context) {
        sharedPref = context.getSharedPreferences(SHARED, MODE_PRIVATE);
        editor = sharedPref.edit();
    }

    public void storeUserSession(UserSession session) {
        editor.putString(Name, session.getUsername());
        editor.putString(Photo, session.getPhoto_url());
        editor.putInt(Rank, session.getUser_Rank());
        editor.putString(Sid, session.getUser_id());
        editor.putBoolean(Ban, session.getUser_Ban());
        editor.putString(Latitude, session.getLatitude());
        editor.putString(Longitude, session.getLongitude());
        editor.apply();
    }

    public void clearUserSession() {
        editor.putString(Name, null);
        editor.putString(Photo, null);
        editor.putInt(Rank, 1);
        editor.putString(Sid, null);
        editor.putBoolean(Ban, false);
        editor.putString(Latitude, null);
        editor.putString(Longitude, null);
        editor.apply();
    }

    public UserSession getUserSession() {
        UserSession session = new UserSession();
        session.setUsername( sharedPref.getString(Name, null) );
        session.setPhoto_url( sharedPref.getString(Photo, null) );
        session.setUser_Rank( sharedPref.getInt(Rank, 1) );
        session.setUser_id( sharedPref.getString(Sid, "") );
        session.setUser_Ban( sharedPref.getBoolean(Ban, false) );
        session.setLatitude(sharedPref.getString(Latitude,"59.946104"));
        session.setLongitude(sharedPref.getString(Longitude,"30.306048"));
        return session;
    }

    public void setFilterDistance(float radius) {
        editor.putFloat(FILTER_RADIUS_DISTANCE, radius);
        editor.commit();
    }

    public float getFilterDistance() {
        return  sharedPref.getFloat(FILTER_RADIUS_DISTANCE, 0);
    }
}

我怎么称呼：

UserAccessSession tes = UserAccessSession.getInstance(getActivity().getApplicationContext());
                UserSession test = tes.getUserSession();

但在test.getLatitude()或test.getLongitude()中，我有空值。在使用getUser_Rank和getUsername或其他值的主活动中，有时也会发生同样的情况。我做错了什么，该如何解决呢？在地图上，在重新打开后，我从SharedPref获得数据，并且地图摄像机移动到我需要的地方。

我添加这样的数据

UserSession userSession = new UserSession();
                UserAccessSession session = UserAccessSession.getInstance(MainActivity.this);
                String sid = User_SID;
                userSession.setUsername(UserName);
                userSession.setPhoto_url(Photo_URL);
                userSession.setUser_Rank(Rank);
                userSession.setUser_id(sid);
                session.storeUserSession(userSession);

我添加的坐标如下：

userAccess = UserAccessSession.getInstance(MainActivity.this);
                userSession = userAccess.getUserSession();
                userSession.setLatitude(String.valueOf(location.getLatitude()));
                userSession.setLongitude(String.valueOf(location.getLongitude()));
                userAccess.storeUserSession(userSession);

谢谢你的帮助。我为可能重复这个问题而道歉。我英语说得不好，很难找到信息。

Answer 1

我想，由于您访问的是来自不同的来源，问题会发生。

使用默认的共享首选项，它使用单个文件来存储，而不是使用不同的文件。

替换此context.getSharedPreferences(SHARED, MODE_PRIVATE);

用这个PreferenceManager.getDefaultSharedPreferences(context.getApplicationContext());

Answer 2

更改设置为获取

    public UserSession getUserSession() {
     UserSession session = new UserSession();
    session.getUsername( sharedPref.getString(Name, null) );
    session.getPhoto_url( sharedPref.getString(Photo, null) );
    session.getUser_Rank( sharedPref.getInt(Rank, 1) );
    session.getUser_id( sharedPref.getString(Sid, "") );
    session.getUser_Ban( sharedPref.getBoolean(Ban, false) );
    session.getLatitude(sharedPref.getString(Latitude,"59.946104"));
    session.getLongitude(sharedPref.getString(Longitude,"30.306048"));
    return session;
}

Answer 3

我太傻了。

userAccess = UserAccessSession.getInstance(MainActivity.this);
                userSession = userAccess.getUserSession();
                userSession.setLatitude(String.valueOf(location.getLatitude()));
                userSession.setLongitude(String.valueOf(location.getLongitude()));
                userAccess.storeUserSession(userSession);

此呼叫清除了现有数据。把坐标转换成单独的方法，一切正常。