How to store a set of ArrayList values using sharedpreference

Question

The code below retrieves multiple selected contacts and stores it in the form of ArrayList but once I close the application and open the selected contact list is removed ,so the data should be stored so that once I close and open the app the data remains until the data is removed. Can anyone please help me to store the ArrayList values using shared preference .

 private void chooseContact() {
    Intent intentContactPick = new Intent(MainActivity.this,ContactsPickerActivity.class);
    MainActivity.this.startActivityForResult(intentContactPick,CONTACT_PICK_REQUEST);
}

@Override
public void onActivityResult(int requestCode,int resultCode,Intent data){
    super.onActivityResult(requestCode, resultCode, data);

    if(requestCode == CONTACT_PICK_REQUEST && resultCode == RESULT_OK){


        ArrayList<Contact> selectedContacts = data.getParcelableArrayListExtra("SelectedContacts");

        String display="";
        for(int i=0;i<selectedContacts.size();i++){

            display += (i+1)+". "+selectedContacts.get(i).toString()+"\n";

        }
        contactsDisplay.setText("Selected Contacts : \n\n"+display);

    }

}

}

the below code is the ArrayList which holds the selected contact values.

 ArrayList<Contact> selectedContacts = data.getParcelableArrayListExtra("SelectedContacts");

You can store only Primitive datatype in SharedPreferences... But you can store ArrayList in SharedPreferences using Gson library — ak sacha, Jan 20 '17 at 10:53
Possible duplicate of [Save ArrayList to SharedPreferences](http://stackoverflow.com/questions/7057845/save-arraylist-to-sharedpreferences) — Akshay Tilekar, Jan 27 '17 at 08:53

score 1 · Answer 1 · answered Jan 20 '17 at 10:56

You have different options.

Use a service and run it on background so data will not lost on close.
Write the data to an object and save it as file and read the object when you need the data.
Write object to shared preference.

Convert your array or object to Json with Gson library and store your data as String in json format.

Save;

SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
Editor editor = sharedPrefs.edit();
Gson gson = new Gson();

String json = gson.toJson(arrayList);

editor.putString(TAG, json);
editor.commit();

Read;

SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
Gson gson = new Gson();
String json = sharedPrefs.getString(TAG, null);
Type type = new TypeToken<ArrayList<ArrayObject>>() {}.getType();
ArrayList<ArrayObject> arrayList = gson.fromJson(json, type);

use import java.lang.reflect.Type for avoiding errors.

What does context refer in the above code and how am I supposed to use it in my code above because i am coming cross lot of errors. — Meghana, Jan 20 '17 at 11:06

score 0 · Answer 2 · answered Jan 20 '17 at 10:57

See this.

Store

public void storeData(Context context,List<Contact> offlineData){

        SharedPreferences preferences=context.getSharedPreferences("contact_prefs",Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = preferences.edit();

        Gson gson=new Gson();
        editor.putString("data",gson.toJson(offlineData));
        editor.apply();
    }

Read

 public List<Contact> getData(Context context){
        SharedPreferences preferences=context.getSharedPreferences("contact_prefs",Context.MODE_PRIVATE);
        Gson gson = new Gson();
        return gson.fromJson(preferences.getString("data",null), new TypeToken<List<Photo>>() {
        }.getType());

    }

Alon Aviram · Answer 3 · 2017-01-20T15:54:49.017

0

Ranjith KP answer is great. dont forget to add dependecy:

compile 'com.google.code.gson:gson:2.8.0'

for the context u can pass ur activity (just use 'this' instead).

TAG - thats just a string, add

String TAG = "tag";

on your activity's members.

edited Jan 20 '17 at 15:54

answered Jan 20 '17 at 11:02

Alon Aviram

190
1
15

Febin K R · Answer 4 · 2017-01-20T11:47:28.620

0

To save a key value pair to the shared preferences :

SharedPreferences sharedPreference = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
Editor editor = sharedPreference.edit();
editor.putString(key, value);
editor.apply();

context : Pass the calling context or Base Context or Application Context (getContext() in Fragments or getBaseContext() in Activity)

edited Jan 20 '17 at 11:47

answered Jan 20 '17 at 11:40

Febin K R

886
2
11
21

How to store a set of ArrayList values using sharedpreference

4 Answers4