我需要在许多地方获得用户对象,其中包含许多字段。登录后,我想保存/存储这些用户对象。我们如何实现这种场景?

我不能这样存储它:

SharedPreferences.Editor prefsEditor = myPrefs.edit();
prefsEditor.putString("BusinessUnit", strBusinessUnit);

当前回答

有两个文件解决了共享首选项的所有问题

1)AppPersistence.java

    public class AppPersistence {
    public enum keys {
        USER_NAME, USER_ID, USER_NUMBER, USER_EMAIL, USER_ADDRESS, CITY, USER_IMAGE,
        DOB, MRG_Anniversary, COMPANY, USER_TYPE, support_phone
    }

    private static AppPersistence mAppPersistance;
    private SharedPreferences sharedPreferences;

    public static AppPersistence start(Context context) {
        if (mAppPersistance == null) {
            mAppPersistance = new AppPersistence(context);
        }
        return mAppPersistance;
    }

    private AppPersistence(Context context) {
        sharedPreferences = context.getSharedPreferences(context.getString(R.string.prefrence_file_name),
                Context.MODE_PRIVATE);
    }

    public Object get(Enum key) {
        Map<String, ?> all = sharedPreferences.getAll();
        return all.get(key.toString());
    }

    void save(Enum key, Object val) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        if (val instanceof Integer) {
            editor.putInt(key.toString(), (Integer) val);
        } else if (val instanceof String) {
            editor.putString(key.toString(), String.valueOf(val));
        } else if (val instanceof Float) {
            editor.putFloat(key.toString(), (Float) val);
        } else if (val instanceof Long) {
            editor.putLong(key.toString(), (Long) val);
        } else if (val instanceof Boolean) {
            editor.putBoolean(key.toString(), (Boolean) val);
        }
        editor.apply();
    }

    void remove(Enum key) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.remove(key.toString());
        editor.apply();
    }

    public void removeAll() {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        editor.apply();
    }
}

2)AppPreference.java

public static void setPreference(Context context, Enum Name, String Value) {
        AppPersistence.start(context).save(Name, Value);
    }

    public static String getPreference(Context context, Enum Name) {
        return (String) AppPersistence.start(context).get(Name);
    }

    public static void removePreference(Context context, Enum Name) {
        AppPersistence.start(context).remove(Name);
    }
}

现在你可以保存,删除或者获取,

保存

AppPreference.setPreference(context, AppPersistence.keys.USER_ID, userID);

删除

AppPreference.removePreference(context, AppPersistence.keys.USER_ID);

-get

 AppPreference.getPreference(context, AppPersistence.keys.USER_ID);

其他回答

更好的方法是创建一个全局Constants类来保存键或变量以获取或保存数据。

要保存数据,请调用此方法保存来自任何地方的数据。

public static void saveData(Context con, String variable, String data)
{
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(con);
    prefs.edit().putString(variable, data).commit();
}

用它来获取数据。

public static String getData(Context con, String variable, String defaultValue)
{
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(con);
    String data = prefs.getString(variable, defaultValue);
    return data;
}

像这样的方法就可以了

public static User getUserInfo(Context con)
{
    String id =  getData(con, Constants.USER_ID, null);
    String name =  getData(con, Constants.USER_NAME, null);
    if(id != null && name != null)
    {
            User user = new User(); //Hope you will have a user Object.
            user.setId(id);
            user.setName(name);
            //Here set other credentials.
            return user;
    }
    else
    return null;
}

有两个文件解决了共享首选项的所有问题

1)AppPersistence.java

    public class AppPersistence {
    public enum keys {
        USER_NAME, USER_ID, USER_NUMBER, USER_EMAIL, USER_ADDRESS, CITY, USER_IMAGE,
        DOB, MRG_Anniversary, COMPANY, USER_TYPE, support_phone
    }

    private static AppPersistence mAppPersistance;
    private SharedPreferences sharedPreferences;

    public static AppPersistence start(Context context) {
        if (mAppPersistance == null) {
            mAppPersistance = new AppPersistence(context);
        }
        return mAppPersistance;
    }

    private AppPersistence(Context context) {
        sharedPreferences = context.getSharedPreferences(context.getString(R.string.prefrence_file_name),
                Context.MODE_PRIVATE);
    }

    public Object get(Enum key) {
        Map<String, ?> all = sharedPreferences.getAll();
        return all.get(key.toString());
    }

    void save(Enum key, Object val) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        if (val instanceof Integer) {
            editor.putInt(key.toString(), (Integer) val);
        } else if (val instanceof String) {
            editor.putString(key.toString(), String.valueOf(val));
        } else if (val instanceof Float) {
            editor.putFloat(key.toString(), (Float) val);
        } else if (val instanceof Long) {
            editor.putLong(key.toString(), (Long) val);
        } else if (val instanceof Boolean) {
            editor.putBoolean(key.toString(), (Boolean) val);
        }
        editor.apply();
    }

    void remove(Enum key) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.remove(key.toString());
        editor.apply();
    }

    public void removeAll() {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        editor.apply();
    }
}

2)AppPreference.java

public static void setPreference(Context context, Enum Name, String Value) {
        AppPersistence.start(context).save(Name, Value);
    }

    public static String getPreference(Context context, Enum Name) {
        return (String) AppPersistence.start(context).get(Name);
    }

    public static void removePreference(Context context, Enum Name) {
        AppPersistence.start(context).remove(Name);
    }
}

现在你可以保存,删除或者获取,

保存

AppPreference.setPreference(context, AppPersistence.keys.USER_ID, userID);

删除

AppPreference.removePreference(context, AppPersistence.keys.USER_ID);

-get

 AppPreference.getPreference(context, AppPersistence.keys.USER_ID);

在SharedPreferences中存储Model的数组列表

Add this dependency implementation 'com.google.code.gson:gson:2.8.8' Then after you convert your Model Class into JSON using Gson. Gson gson = new Gson(); String json = gson.toJson(chModelArrayList); //here chModelArrayList is a ArrayList<Model> of Model Class Then after you can add this string to SharedPreferences SharedPreferences preferences; //Create Object of SharedPreferences SharedPreferences.Editor editor; //Create Object of SharedPreferences.Editor //initialize SharedPreferences preferences = activity.getPreferences(Context.MODE_PRIVATE); editor = preferences.edit(); //Add-In SharedPreferences editor.putString(key, json); editor.commit(); for your list from SharedPreferences String json = preferences.getString(key, defVal); Gson gson = new Gson(); //Pass Your Model ArrayList in TypeToken Type type = new TypeToken<ArrayList<ChModel>>() {}.getType(); //here you get your list ArrayList<ChModel> switchGroup1 = gson.fromJson(json, type);

我知道这个帖子有点旧了。 但我还是要把这个贴出来,希望它能帮助到一些人。 通过将对象序列化为String,可以将任何Object的字段存储为共享首选项。 这里我使用GSON存储共享首选项的任何对象。

保存对象到首选项:

public static void saveObjectToSharedPreference(Context context, String preferenceFileName, String serializedObjectKey, Object object) {
    SharedPreferences sharedPreferences = context.getSharedPreferences(preferenceFileName, 0);
    SharedPreferences.Editor sharedPreferencesEditor = sharedPreferences.edit();
    final Gson gson = new Gson();
    String serializedObject = gson.toJson(object);
    sharedPreferencesEditor.putString(serializedObjectKey, serializedObject);
    sharedPreferencesEditor.apply();
}

从首选项检索对象:

public static <GenericClass> GenericClass getSavedObjectFromPreference(Context context, String preferenceFileName, String preferenceKey, Class<GenericClass> classType) {
    SharedPreferences sharedPreferences = context.getSharedPreferences(preferenceFileName, 0);
    if (sharedPreferences.contains(preferenceKey)) {
        final Gson gson = new Gson();
        return gson.fromJson(sharedPreferences.getString(preferenceKey, ""), classType);
    }
    return null;
}

注意:

记得在gradle的dependencies中添加compile 'com.google.code.gson:gson:2.6.2'。

例子:

//assume SampleClass exists
SampleClass mObject = new SampleObject();

//to store an object
saveObjectToSharedPreference(context, "mPreference", "mObjectKey", mObject);

//to retrive object stored in preference
mObject = getSavedObjectFromPreference(context, "mPreference", "mObjectKey", SampleClass.class);

更新:

正如@Sharp_Edge在评论中指出的那样,上述解决方案不适用于List。

稍微修改一下getSavedObjectFromPreference()的签名——从Class<GenericClass> classType到Type classType将使这个解决方案一般化。修改后的函数签名

public static <GenericClass> GenericClass getSavedObjectFromPreference(Context context, String preferenceFileName, String preferenceKey, Type classType)

用于调用,

getSavedObjectFromPreference(context, "mPreference", "mObjectKey", (Type) SampleClass.class)

编码快乐!

步骤1:在java文件中复制粘贴这两个函数。

 public void setDefaults(String key, String value, Context context) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = preferences.edit();
        editor.putString(key, value);
        editor.commit();
    }


    public static String getDefaults(String key, Context context) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        return preferences.getString(key, null);
    }

步骤2: 为了节省使用:

 setDefaults("key","value",this);

检索使用:

String retrieve= getDefaults("key",this);

你可以通过使用不同的键名来设置不同的共享首选项,比如:

setDefaults("key1","xyz",this);

setDefaults("key2","abc",this);

setDefaults("key3","pqr",this);