Question

I am working on a small Android App!

I have a class MyPref

public class MyPref{
{
java.util.Calendar cal;
int id;
String name;
//some more methods and constructor
}

I need to store an array of MyPref objects to sharedpreferences…

java.util.ArrayList<MyPref> array=new java.util.ArrayList<MyPref>();
array.add(//MyPref object);
array.add(//MyPref object);

now how can I store this ArrayList object to sharedpreferences..
I tried..

JSONObject o=new JSONObject();
o.put("list",array);
SharedPreferences s=PreferenceManager.getDefaultSharedPreferences(this);
Editor edt=s.edit();
edt.putString("mylist",o.toString());
edt.commit();

but this doesn’t worked!
is there any other alternative??
plz help me..
thanx in advace..

Answer 1

JSONObject o=new JSONObject();
o.put("list",array);

I may be wrong but I’m pretty sure you can’t use JSONObject.put(...) to put an arbitrary Java object into a JSONObject. From the docs…

public JSONObject put (String name, Object value)

value a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities.

There’s no mention of being able to put a Java object of any other type and you’re trying to put an ArrayList<MyPref>.