How do you save/store objects in SharedPreferences on Android?

Better is to Make a global Constants class to save key or variables to fetch or save data.

To save data call this method to save data from every where.

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

Use it to get data.

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

and a method something like this will do the trick

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;
}

To add to @MuhammadAamirALi's answer, you can use Gson to save and retrieve a list of objects

Save List of user-defined objects to SharedPreferences

public static final String KEY_CONNECTIONS = "KEY_CONNECTIONS";
SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();

User entity = new User();
// ... set entity fields

List<Connection> connections = entity.getConnections();
// convert java object to JSON format,
// and returned as JSON formatted string
String connectionsJSONString = new Gson().toJson(connections);
editor.putString(KEY_CONNECTIONS, connectionsJSONString);
editor.commit();

Get List of user-defined objects from SharedPreferences

String connectionsJSONString = getPreferences(MODE_PRIVATE).getString(KEY_CONNECTIONS, null);
Type type = new TypeToken < List < Connection >> () {}.getType();
List < Connection > connections = new Gson().fromJson(connectionsJSONString, type);

I know this thread is bit old. But I'm going to post this anyway hoping it might help someone. We can store fields of any Object to shared preference by serializing the object to String. Here I have used GSON for storing any object to shared preference.

Save Object to Preference :

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();
}

Retrieve Object from Preference:

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;
}

Note :

Remember to add compile 'com.google.code.gson:gson:2.6.2' to dependencies in your gradle.

Example :

//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);

Update:

As @Sharp_Edge pointed out in comments, the above solution does not work with List.

A slight modification to the signature of getSavedObjectFromPreference() - from Class<GenericClass> classType to Type classType will make this solution generalized. Modified function signature,

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

For invoking,

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

Happy Coding!

You can use gson.jar to store class objects into SharedPreferences. You can download this jar from google-gson

Or add the GSON dependency in your Gradle file:

implementation 'com.google.code.gson:gson:2.8.8'

you can find latest version here

Creating a shared preference:

SharedPreferences  mPrefs = getPreferences(MODE_PRIVATE);

To save:

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

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

To retrieve:

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