Shared Preference not saving value

Question

I am just learning to build some applications in Android. Out of curiosity, I have a small and weird problem using Shared Preferences. If someone can help me addressing this issue , I would be most thankful to them. Anyways,here goes the problem. I have 2 Activities. 1. Activity 1 : Consists of just one button that will get you to the next activity. 2. Activity 2 : Consists of a listview with checkbox (simple_list_item_checked or simple_list_multi_choice_item).

My question is: I open my application, hit the button on my first activity screen, this moves me to the second activity. I check an item in the listview. I hit the back button on my phone, go to the first activity, again press the button on my activity 1 screen, this takes me to the list again. Now I just leave my list item checked(I don't change anything that is already checked previously). Now again, I hit back button on my phone, get back to activity one. Now again when I press the button on my activity one screen. It takes me back to the listview but SURPRISINGLY nothing is checked. To note a point here, I had also set and retrieved my shared preference.

MY QUESTION IN A SINGLE LINE IS : If I don't change a value in the check list while I'm in that Activity and then go back to the Main Activity, and get back to the same check list activity, my shared preference does not load what has been saved earlier. Is this the normal behavior of Shared Preference or is it a problem in the coding.

I would just like to know how preference values are saved and retrieved and how long does a preference save a value ? I mean the lifecycle of the saved value in preference.

MY SECOND QUESTION : Also, I would like to know one more thing in activity life cycle. When I am in the second activity as explained in the above example. Now I press the home button , now I go to the background tasks and clear all the tasks(Apps) that are running . Now, my question is which state of activity life cycle is followed or what will be the final activity lifecycle before i clear all my apps from the background ? Please someone help me out on this. Thanks to all those creative developers out there in advance. Hope someone can solve my issue.

public class Secondact extends ListActivity {
    ListView list;
    SharedPreferences pref;
     int pos,itemposition,positionvalue;
     boolean boolval,checkvalue;
     SharedPreferences.Editor editor;
     @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
          // setContentView(R.layout.secondact);
            Toast.makeText(getApplicationContext(), "ONCREATE", 50).show();

            list=getListView();

           String[] family_array=this.getResources().getStringArray(R.array.family);
           ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_multiple_choice,family_array);
           list.setAdapter(adapter);
           list.setChoiceMode(1);
           pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
         pos=pref.getInt("itempos", pos);
             boolval=pref.getBoolean("boolvalue", true);
            list.setItemChecked(pos, boolval);
            Toast.makeText(getApplicationContext(), "DATA LOADED ITEM NO:"+pos, 50).show();

           list.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // TODO Auto-generated method stub


                pos=position;
                list.setItemChecked(pos, true);
                pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
                editor=pref.edit();
                editor.putInt("itempos", pos);
                editor.putBoolean("boolvalue", list.isItemChecked(pos));
                editor.commit();
            }
        });

}

    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
     editor=pref.edit();
        editor.putInt("itempos", pos);
        editor.putBoolean("boolvalue", list.isItemChecked(pos));
        editor.commit();
    //  Toast.makeText(getApplicationContext(), "PAUSE", 50).show();

    }

    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
         pos=pref.getInt("itempos", pos);
         boolval=pref.getBoolean("boolvalue", true);
        list.setItemChecked(pos, boolval);
        //Toast.makeText(getApplicationContext(), "RESUME", 50).show();

    }

    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
         editor=pref.edit();
        editor.putInt("itempos", pos);
        editor.putBoolean("boolvalue", list.isItemChecked(pos));
        editor.commit();
        Toast.makeText(getApplicationContext(), "DESTROY", 50).show();
        Toast.makeText(getApplicationContext(), "DATA SAVED ITEM NO:"+pos, 50).show();

    }

    @Override
    protected void onRestart() {
        // TODO Auto-generated method stub
        super.onRestart();
        pref=PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
     pos=pref.getInt("itempos", pos);
         boolval=pref.getBoolean("boolvalue", true);
        list.setItemChecked(pos, boolval);
        //Toast.makeText(getApplicationContext(), "RESTART", 50).show();

    }

    @Override
    protected void onSaveInstanceState(Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        savedInstanceState.putInt("itempositionno", positionvalue);
        savedInstanceState.putBoolean("checkvalue", true);
        Toast.makeText(getApplicationContext(), "ONSAVEINSTANCE", 50).show();
        list.setItemChecked(pos, checkvalue);
        super.onSaveInstanceState(savedInstanceState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        pos=savedInstanceState.getInt("itempositionno", pos);
         checkvalue=savedInstanceState.getBoolean("checkvalue", true);
        list.setItemChecked(pos, checkvalue);
        Toast.makeText(getApplicationContext(), "ONRESTOREINSTANCE", 50).show();
        super.onRestoreInstanceState(savedInstanceState);
    }




}

I'm at office. Will update the code in a couple of hours. Pardon me for that.Completely forgot to attach the coding. Please do help me once I update the question with some codes in it. — Krish3090, Jul 07 '14 at 12:43
Hi guys !Updated with the code as requested. Please read through and let me know if I had done any mistakes. — Krish3090, Jul 07 '14 at 16:06

score 4 · Accepted Answer · edited May 23 '17 at 11:50

I would just like to know how preference values are saved and retrieved and how long does a preference save a value ? I mean the lifecycle of the saved value in preference.

A single line reply to your single line question -

It is saved throughout the life-cycle of the application unless you yourself clear it.

To obtain shared preferences:

SharedPreferences prefs = this.getSharedPreferences(
      "com.example.app", Context.MODE_PRIVATE);

To read preferences:

String dateTimeKey = "com.example.app.datetime";

// use a default value using new Date()
long l = prefs.getLong(dateTimeKey, new Date().getTime());

To edit and save preferences

In order to edit(clear) -

SharedPreferences.Editor editor = prefs.edit();
    editor.clear();
    editor.commit();

In order to save -

Date dt = getSomeDate();
prefs.edit().putLong(dateTimeKey, dt.getTime()).commit();

Read - how-to-use-sharedpreferences-in-android-to-store-fetch-and-edit-values.

Which state of activity life cycle is followed or what will be the final activity life-cycle before I clear all my apps from the background ?

Depends on your requirement. No need to follow final activity life-cycle to do this. For example - When the user logs out from the application, preferences related to the user are of no use and can be cleared independent of the life-cycle just after the log out button press.

Ups for reading through the long post and answering so clearly! — cokeby190, Jul 07 '14 at 12:48
@Ved Prakash : Thanks man ! Appreciate that. Reading such a huge post and answering to the point . Great! Now, when you look at my question, the preference stays only for the first time. The second time , when I go to the check list activity and I don't change anything(leave the same value as checked earlier), now when I hit the back button and get to the main activity and getting back again to the check list activity, my CHECK MARK is gone. This is where I have a doubt. Coz, I had set the preference values in ON PAUSE, ON RESUME, ON DESTORY, etc. But still don't get the value checked earlier. — Krish3090, Jul 07 '14 at 12:54

score 1 · Answer 2 · edited Apr 29 '18 at 04:36

Alright, for those who are suffering from the same problem of the shared preference not maintaining the value on activity switch. This piece of logic does the trick:

Set your default value of your row in the listview like this

sp.getInt("CheckedValue",

pass the position of the ealier checked row as the default one

    viz.Listitem.getCheckedItemPosition());

This will save the checked value throughout your application's life cycle and/or activity life cycle.

NOTE:

Make sure to clear your sharedpreference before commit() so as to avoid the hectic memory usage of your app.

Shared Preference not saving value

2 Answers2

To obtain shared preferences:

To read preferences:

To edit and save preferences