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

这么多好答案,她是我的2美分

我更喜欢使用内联函数和旧风格的put和get值

object PreferenceHelper {

    private const val PREFERENCES_KEY = "MyLocalPreference"

    private fun getPreference(context: Context): SharedPreferences {
        return context.getSharedPreferences(
            PREFERENCES_KEY,
            Context.MODE_PRIVATE
        )
    }

    fun setBoolean(appContext: Context, key: String?, value: Boolean?) =
        getPreference(appContext).edit().putBoolean(key, value!!).apply()

    fun setInteger(appContext: Context, key: String?, value: Int) =
        getPreference(appContext).edit().putInt(key, value).apply()

    fun setFloat(appContext: Context, key: String?, value: Float) =
        getPreference(appContext).edit().putFloat(key, value).apply()

    fun setString(appContext: Context, key: String?, value: String?) =
        getPreference(appContext).edit().putString(key, value).apply()

    // To retrieve values from shared preferences:
    fun getBoolean(appContext: Context, key: String?, defaultValue: Boolean?): Boolean =
        getPreference(appContext).getBoolean(key, defaultValue!!)

    fun getInteger(appContext: Context, key: String?, defaultValue: Int): Int =
        getPreference(appContext)
            .getInt(key, defaultValue)

    fun getString(appContext: Context, key: String?, defaultValue: String?): String? =
        getPreference(appContext)
            .getString(key, defaultValue)


}

使用

PreferenceHelper.setString(context,"CUSTOMER_NAME", "HITESH")

Toast.makeText(context, "Hello " + PreferenceHelper.getString(context,"CUSTOMER_NAME", "User"), Toast.LENGTH_LONG).show()

其他回答

你可以保存对象在首选项不使用任何库,首先你的对象类必须实现Serializable:

public class callModel implements Serializable {

private long pointTime;
private boolean callisConnected;

public callModel(boolean callisConnected,  long pointTime) {
    this.callisConnected = callisConnected;
    this.pointTime = pointTime;
}
public boolean isCallisConnected() {
    return callisConnected;
}
public long getPointTime() {
    return pointTime;
}

}

然后你可以很容易地使用这两个方法来转换对象到字符串和字符串到对象:

 public static <T extends Serializable> T stringToObjectS(String string) {
    byte[] bytes = Base64.decode(string, 0);
    T object = null;
    try {
        ObjectInputStream objectInputStream = new ObjectInputStream(new ByteArrayInputStream(bytes));
        object = (T) objectInputStream.readObject();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return object;
}

 public static String objectToString(Parcelable object) {
    String encoded = null;
    try {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
        objectOutputStream.writeObject(object);
        objectOutputStream.close();
        encoded = new String(Base64.encodeToString(byteArrayOutputStream.toByteArray(), 0));
    } catch (IOException e) {
        e.printStackTrace();
    }
    return encoded;
}

保存:

SharedPreferences  mPrefs = getPreferences(MODE_PRIVATE);
Editor prefsEditor = mPrefs.edit();
prefsEditor.putString("MyObject", objectToString(callModelObject));
prefsEditor.commit();

阅读

String value= mPrefs.getString("MyObject", "");
MyObject obj = stringToObjectS(value);

我在使用已接受的答案访问跨活动的共享首选项数据时遇到了麻烦。在这些步骤中,您将为getSharedPreferences提供一个名称以访问它。

在构建中添加以下依赖项。Gradle脚本下的gradel (Module: app)文件:

implementation 'com.google.code.gson:gson:2.8.5'

保存:

MyObject myObject = new MyObject;
//set variables of 'myObject', etc.

SharedPreferences mPrefs = getSharedPreferences("Name", Context.MODE_PRIVATE);

Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myObject);
prefsEditor.putString("Key", json);
prefsEditor.commit();

在不同的活动中检索:

SharedPreferences mPrefs = getSharedPreferences("Name", Context.MODE_PRIVATE);

Gson gson = new Gson();
String json = mPrefs.getString("Key", "");
MyObject obj = gson.fromJson(json, MyObject.class);

看这里,这可以帮助你:

public static boolean setObject(Context context, Object o) {
        Field[] fields = o.getClass().getFields();
        SharedPreferences sp = context.getSharedPreferences(o.getClass()
                .getName(), Context.MODE_PRIVATE);
        Editor editor = sp.edit();
        for (int i = 0; i < fields.length; i++) {
            Class<?> type = fields[i].getType();
            if (isSingle(type)) {
                try {
                    final String name = fields[i].getName();
                    if (type == Character.TYPE || type.equals(String.class)) {
                        Object value = fields[i].get(o);
                        if (null != value)
                            editor.putString(name, value.toString());
                    } else if (type.equals(int.class)
                            || type.equals(Short.class))
                        editor.putInt(name, fields[i].getInt(o));
                    else if (type.equals(double.class))
                        editor.putFloat(name, (float) fields[i].getDouble(o));
                    else if (type.equals(float.class))
                        editor.putFloat(name, fields[i].getFloat(o));
                    else if (type.equals(long.class))
                        editor.putLong(name, fields[i].getLong(o));
                    else if (type.equals(Boolean.class))
                        editor.putBoolean(name, fields[i].getBoolean(o));

                } catch (IllegalAccessException e) {
                    LogUtils.e(TAG, e);
                } catch (IllegalArgumentException e) {
                    LogUtils.e(TAG, e);
                }
            } else {
                // FIXME 是对象则不写入
            }
        }

        return editor.commit();
    }

https://github.com/AltasT/PreferenceVObjectFile/blob/master/PreferenceVObjectFile/src/com/altas/lib/PreferenceUtils.java

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);
// SharedPrefHelper is a class contains the get and save sharedPrefernce data
public class SharedPrefHelper {

    // save data in sharedPrefences
    public static void setSharedOBJECT(Context context, String key, 
                                           Object value) {

        SharedPreferences sharedPreferences =  context.getSharedPreferences(
                context.getPackageName(), Context.MODE_PRIVATE);

        SharedPreferences.Editor prefsEditor = sharedPreferences.edit();
        Gson gson = new Gson();
        String json = gson.toJson(value);
        prefsEditor.putString(key, json);
        prefsEditor.apply();
    }

    // get data from sharedPrefences 
    public static Object getSharedOBJECT(Context context, String key) {

         SharedPreferences sharedPreferences = context.getSharedPreferences(
                           context.getPackageName(), Context.MODE_PRIVATE);

        Gson gson = new Gson();
        String json = sharedPreferences.getString(key, "");
        Object obj = gson.fromJson(json, Object.class);
        User objData = new Gson().fromJson(obj.toString(), User.class);
        return objData;
    }
}
// save data in your activity

User user = new User("Hussein","h@h.com","3107310890983");        
SharedPrefHelper.setSharedOBJECT(this,"your_key",user);        
User data = (User) SharedPrefHelper.getSharedOBJECT(this,"your_key");

Toast.makeText(this,data.getName()+"\n"+data.getEmail()+"\n"+data.getPhone(),Toast.LENGTH_LONG).show();
// User is the class you want to save its objects

public class User {

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    private String name,email,phone;
    public User(String name,String email,String phone){
          this.name=name;
          this.email=email;
          this.phone=phone;
    }
}
// put this in gradle

compile 'com.google.code.gson:gson:2.7'

希望这对你有所帮助:)