store and retrieve a class object in shared preference

Question

In Android can we store an object of a class in shared preference and retrieve the object later   If it is possible how to do it  If it is not possible what are the other possibilities of doing it    I know that serialization is one option  but I am looking for possibilities using shared preference

User · Answer

Yes we can do this using Gson

Download Working code from GitHub

SharedPreferences mPrefs = getPreferences(MODE_PRIVATE);

For save

Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(myObject); // myObject - instance of MyObject
prefsEditor.putString("MyObject", json);
prefsEditor.commit();

For get

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

Update1

The latest version of GSON can be downloaded from github.com/google/gson.

Update2

If you are using Gradle/Android Studio just put following in build.gradle dependencies section -

implementation 'com.google.code.gson:gson:2.6.2'

User · Answer

Yes  You can store and retrive the object using Sharedpreference

User · Answer

we can use Outputstream to output our Object to internal memory  And convert to string then save in preference  For example       mPrefs   getPreferences MODE PRIVATE       SharedPreferences Editor ed   mPrefs edit        ByteArrayOutputStream arrayOutputStream   new ByteArrayOutputStream         ObjectOutputStream objectOutput      try           objectOutput   new ObjectOutputStream arrayOutputStream           objectOutput writeObject object           byte   data   arrayOutputStream toByteArray            objectOutput close            arrayOutputStream close             ByteArrayOutputStream out   new ByteArrayOutputStream            Base64OutputStream b64   new Base64OutputStream out  Base64 DEFAULT           b64 write data           b64 close            out close             ed putString key  new String out toByteArray               ed commit          catch  IOException e            e printStackTrace            when we need to extract Object from Preference  Use the code as below      byte   bytes   mPrefs getString indexName        getBytes        if  bytes length    0            return null            ByteArrayInputStream byteArray   new ByteArrayInputStream bytes       Base64InputStream base64InputStream   new Base64InputStream byteArray  Base64 DEFAULT       ObjectInputStream in      in   new ObjectInputStream base64InputStream       MyObject myObject    MyObject  in readObject

User · Answer

Not possible    You can only store  simple values in SharedPrefences SharePreferences Editor  What particularly about the class do you need to save

User · Answer

Do you need to retrieve the object even after the application shutting donw or just during it s running    You can store it into a database  Or Simply create a custom Application class   public class MyApplication extends Application        private static Object mMyObject         static getter  amp  setter             lt manifest xmlns android  http   schemas android com apk res android  gt       lt application     android name   MyApplication  gt           lt activity       gt                   lt  application gt           lt  manifest gt    And then from every activities do      MyApplication  getApplication  getMyObject      Not really the best way but it works

User · Answer

Using Gson Library   dependencies   compile  com google code gson gson 2 8 2      Store   Gson gson   new Gson      Your json response object value store in json object JSONObject jsonObject   response getJSONObject      Convert json object to string String json   gson toJson jsonObject     Store in the sharedpreference getPrefs   setUserJson json     Retrieve   String json   getPrefs   getUserJson

User · Answer

You could use GSON  using Gradle Build gradle    implementation  com google code gson gson 2 8 0    Then in your code  for example pairs of string boolean with Kotlin            val nestedData   HashMap lt String Boolean gt            for  i in 0  29                nestedData put i toString    true                    val gson   Gson           val jsonFromMap   gson toJson nestedData    Adding to SharedPrefs            val sharedPrefEditor   context getSharedPreferences  prefName  Context MODE PRIVATE  edit           sharedPrefEditor putString  sig types   jsonFromMap          sharedPrefEditor apply     Now to retrieve data    val gson   Gson   val sharedPref  SharedPreferences   context getSharedPreferences  prefName  Context MODE PRIVATE  val json   sharedPref getString  sig types    false   val type   object   TypeToken lt Map lt String  Boolean gt  gt       type val map   gson fromJson json  type  as LinkedTreeMap lt String Boolean gt  for  key in map keys         Log i  myvalues   key toString     map get key  toString

User · Answer

I had the same problem  here s my solution   I have class MyClass and ArrayList lt  MyClass   that I want to save to Shared Preferences  At first I ve added a method to MyClass that converts it to JSON object   public JSONObject getJSONObject         JSONObject obj   new JSONObject        try           obj put  id   this id           obj put  name   this name         catch  JSONException e            e printStackTrace              return obj      Then here s the method for saving object  ArrayList lt  MyClass   items    SharedPreferences mPrefs   context getSharedPreferences  some name   0       SharedPreferences Editor editor   mPrefs edit         Set lt String gt  set  new HashSet lt String gt         for  int i   0  i  lt  items size    i              set add items get i  getJSONObject   toString                editor putStringSet  some name   set       editor commit      And here s the method for retrieving the object   public static ArrayList lt MyClass gt  loadFromStorage         SharedPreferences mPrefs   context getSharedPreferences  some name   0        ArrayList lt MyClass gt  items   new ArrayList lt MyClass gt          Set lt String gt  set   mPrefs getStringSet  some name   null       if  set    null            for  String s   set                try                   JSONObject jsonObject   new JSONObject s                   Long id   jsonObject getLong  id                     String name   jsonObject getString  name                    MyClass myclass   new MyClass id  name                    items add myclass                  catch  JSONException e                    e printStackTrace                         return items      Note that StringSet in Shared Preferences is available since API 11

User · Answer

Using this object --  TinyDB--Android-Shared-Preferences-Turbo its very simple  you can save most of the commonly used objects with it like arrays  integer  strings lists etc

User · Answer

You can use Complex Preferences Android - by Felipe Silvestre library to store your custom objects  Basically  it s using GSON mechanism to store objects  To save object into prefs   User user   new User    user setName  Felipe    user setAge 22    user setActive true     ComplexPreferences complexPreferences   ComplexPreferences getComplexPreferences       this   mypref   MODE PRIVATE   complexPreferences putObject  user   user   complexPreferences commit      And to retrieve it back   ComplexPreferences complexPreferences   ComplexPreferences getComplexPreferences this   mypref   MODE PRIVATE   User user   complexPreferences getObject  user   User class

User · Answer

Common shared preference  CURD  SharedPreference  to Store data in the form of value-key pairs with a simple Kotlin class   var sp   SharedPreference this     Storing Data   To store String  Int and Boolean data we have three methods with the same name and different parameters  Method overloading    save  key-name1   string value   save  key-name2  int value  save  key-name3  boolean    Retrieve Data  To Retrieve the data stored in SharedPreferences use the following methods   sp getValueString  user name   sp getValueInt  user id   sp getValueBoolean  user session  true    Clear All Data  To clear the entire SharedPreferences use the below code    sp clearSharedPreference     Remove Specific Data    sp removeValue  user name     Common Shared Preference Class  import android content Context import android content SharedPreferences  class SharedPreference private val context  Context        private val PREFS NAME    coredata      private val sharedPref  SharedPreferences   context getSharedPreferences PREFS NAME  Context MODE PRIVATE                                                                                                       save all       To Store String data     fun save KEY NAME  String  text  String             val editor  SharedPreferences Editor   sharedPref edit           editor putString KEY NAME  text          editor apply                                                                                                                    To Store Int data     fun save KEY NAME  String  value  Int             val editor  SharedPreferences Editor   sharedPref edit           editor putInt KEY NAME  value          editor apply                                                                                                                    To Store Boolean data     fun save KEY NAME  String  status  Boolean             val editor  SharedPreferences Editor   sharedPref edit           editor putBoolean KEY NAME  status          editor apply                                                                                                              retrieve selected       To Retrieve String     fun getValueString KEY NAME  String   String             return sharedPref getString KEY NAME                                                                                                                       To Retrieve Int     fun getValueInt KEY NAME  String   Int            return sharedPref getInt KEY NAME  0                                                                                                                    To Retrieve Boolean     fun getValueBoolean KEY NAME  String  defaultValue  Boolean   Boolean            return sharedPref getBoolean KEY NAME  defaultValue                                                                                                             delete all        To clear all data     fun clearSharedPreference              val editor  SharedPreferences Editor   sharedPref edit           editor clear           editor apply                                                                                                              delete selected        To remove a specific data     fun removeValue KEY NAME  String            val editor  SharedPreferences Editor   sharedPref edit           editor remove KEY NAME          editor apply             Blog  https   androidkeynotes blogspot com 2020 02 shared-preference html

User · Answer

There is no way to store objects in SharedPreferences  What i did is to create a public class  put all the parameters i need and create setters and getters  i was able to access my objects

[android] store and retrieve a class object in shared preference

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