Store Arraylist of custom objects

Question

I have saved ArrayList of custom objects in the shared preferences like this:

SharedPreferences prefs = context.getSharedPreferences("prefName", Context.MODE_PRIVATE);
Editor editor = prefs.edit();
editor.putStringSet("myList", new Gson().toJson(arraylist).toString());
editor.apply();

By doing this, once values are saved but when i exit from the app and relaunch and try to save new values then the old values are gone.
Any idea how can i save old values and append new ones?
I want to keep all values in the same array and keep array saved to show values every time when the app loads.

Naturally the old values will be gone. If you need to append, then you need to read the original ones, append the new ones and save back. — Aleks G
– Aleks G, Commented Mar 6, 2013 at 8:41

class stacker · Accepted Answer · 2013-03-06 08:47:27Z

1

Read myList from prefName, append arraylist to what was already saved in the preferences, write back myList to preferences.

answered Mar 6, 2013 at 8:47

class stacker

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Bhavesh Jethani · Accepted Answer · 2013-03-06 09:10:59Z

0

This code may be work for you.

 SharedPreferences setting=context.getSharedPreferences("prefName", Activity.MODE_PRIVATE);
 SharedPreferences.Editor edit=setting.edit();
 edit.putStringSet("myList", new Gson().toJson(arraylist).toString());
 edit.commit();

answered Mar 6, 2013 at 9:10

Bhavesh Jethani

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4 Comments

Bhavesh Jethani Over a year ago

whenever you want to change the value put this code in method. call that method once again.

class stacker Over a year ago

I would really like to know who upvoted this answer because it does nothing but replace apply() by commit() which is definitely not the cause of the problem here. Quite to the contrary, it could even create a performance hit on the UI thread.

Noman Over a year ago

I am already doing it man.. Its just saving the things into prefs... Please read my question again.

Bhavesh Jethani Over a year ago

Get that listArray and append the new value in the list then after store it in shared preference.

kajothan · Accepted Answer · 2013-03-06 12:20:15Z

0

I hav faced this problem earlier... Use generics it will append the value rather than replacing the old datas....

answered Mar 6, 2013 at 12:20

kajothan

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1 Comment

kajothan Over a year ago

@Noman Kindly read how to use generics in java.. It may be useful for your future problems...

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