How do I add an int array into shared preferences?

Question

I am trying to save an int array into the shared preferences.

int myInts[]={1,2,3,4};
SharedPreferences prefs = getSharedPreferences(
                        "Settings", 0);
                SharedPreferences.Editor editor = prefs
                        .edit();
                editor.putInt("savedints", myInts);

Since the putInt method does not accept int arrays, I was wondering if anyone knew another way to do this. Thanks

John Slavick · Accepted Answer · 2015-03-29 12:26:47Z

11

Consider JSON. JSON is well integrated into Android and you can serialize any complex type of java object. In your case the following code would be suited well.

// write
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
    JSONArray arr = new JSONArray();
    arr.put(12);
    arr.put(-6);
    prefs.edit().putString("key", arr.toString());
    prefs.edit().commit();
    // read
    try {
        arr = new JSONArray(prefs.getString("key", "[]"));
        arr.getInt(1); // -6
    } catch (JSONException e) {
        e.printStackTrace();
    }

edited Mar 29, 2015 at 12:26

John Slavick

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answered Aug 26, 2011 at 8:34

AZ13

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2 Comments

Sean Over a year ago

the problem with the JSON method is that I would like to change the array and there doesnt seem to be a way to do something like myInt[3]=4 because we're just stacking ints

AZ13 Over a year ago

unfortunately, yes! there is no way of doing this with the json library of the Android framework...

Vineet Shukla · Accepted Answer · 2011-08-26 07:40:59Z

4

you can add only primitive values to sharedpreference ......

refer this doc:

http://developer.android.com/reference/android/content/SharedPreferences.html

answered Aug 26, 2011 at 7:40

Vineet Shukla

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4 Comments

Sean Over a year ago

Do you have a suggestion that I could do to have the same effect?

Vineet Shukla Over a year ago

you can use Sqlite ...and if the data is not too large the u can put int array value one by one to sharedpreference as int value..

Sean Over a year ago

lets say I did the one by one int value. if I named my keys 1.2.3etc could I call it using a for loop like prefs.getInt(i,0)? Or are the keys always strings

Vineet Shukla Over a year ago

you key should be String...you can do that if store the keys in constant file like this public static final String VAR = "var"; and public static final String VAR1 = "var1"; -------now you can use for loop to add and fetch value like this:------for(int i = 1; i <= value; i++){ String yourVarName = pref.getString(AppConstants.VAR + i, ""); }

Michael · Accepted Answer · 2011-08-26 07:58:30Z

3

You can serialize an array to String using TextUtils.join(";", myInts) and the deserialize it back using something like TextUtils. SimpleStringSplitter or implement your own TextUtils.StringSplitter.

answered Aug 26, 2011 at 7:58

Michael

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Comments

Andree · Accepted Answer · 2013-02-03 14:53:44Z

0

If your integers are unique, perhaps you can use putStringSet (see docs). Otherwise you have to resort to serializing / formatting your integer array as String, as suggested by other answers.

answered Feb 3, 2013 at 14:53

Andree

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