sharedpreferences putting an array

Question

how can I use this code in order to add an array and retrieve it later? can I use a simple for loop?

  SharedPreferences settings = getSharedPreferences("isChk", 0);
  SharedPreferences.Editor editor = settings.edit();
  editor.putBoolean("keys",ArrayValue[i] );
  editor.commit();

and how can I then retrieve them and store each element in an array variable can I use this?

for( int i=0; i<myArr.size(); i++){
keys[i] = settings.getBoolean("isChk", false);
isChkb.add(keys[i]);
}

You can only store boolean, int, float, long and Strings. The only way to store an array is to use the String option and add all your variables together and then decode it as an array when you need it again (see answers below). — anthonycr, Mar 08 '14 at 17:04
noooo just save the array to the storage and then read it back when needed — user3368764, Mar 08 '14 at 17:05

ik024 · Answer 1 · 2014-03-08T17:09:32.463

Here is how u do to save Array in Shared Preferences

public static boolean saveTheArray()
{
 SharedPreferences sharedpref = SharedPreferences.getDefaultSharedPreferences(this);
 SharedPreferences.Editor mEdit1 = sharedpref .edit();
 mEdit1.putInt("Status_size", array.size()); //array-> the array to be saved 

for(int i=0;i<array.size();i++)  
{
    mEdit1.remove("Status_" + i);
    mEdit1.putString("Status_" + i, array.get(i));  
}

return mEdit1.commit();

}

To retriev it use the following code:

public static void loadArray(Context mContext)
{  
SharedPreferences mShrdPref = PreferenceManager.getDefaultSharedPreferences(mContext);
array.clear();
int size = mShrdPref.getInt("Status_size", 0);  

for(int i=0;i<size;i++) 
{
    array.add(mShrdPref.getString("Status_" + i, null));
}
}

Hope it helps :)

and in order to get retrieve the array can i use the same function and replace the put by get ? — user3368764, Mar 08 '14 at 17:05
is this still applicable isChkb.add(settings.getBoolean("Status_" + i, false)); after using the puBoolean() so i store boolean values — user3368764, Mar 08 '14 at 17:22

score 2 · Accepted Answer · answered Mar 08 '14 at 17:16

To store an array in sharedPreferences , you can put your array values in a String , then store this String .. and if you you want to get your array value (in our case ,stored in a string) , you get the string and parse it using StringTokenizer like this : (In my example I will store and retreive an array of Boolean)

Put your booleans into a string, delimiting every int by a character, for example a comma, and then save them as a string:

SharedPreferences prefs = getPreferences(MODE_PRIVATE);
Boolean[] list = new Boolean[10];
StringBuilder str = new StringBuilder();
for (int i = 0; i < list.length; i++) {
str.append(list[i]).append(",");
}
prefs.edit().putBoolean("keys", str.toString()).commit();

Get the string and parse it using StringTokenizer:

String savedString = prefs.getString("string", "");
StringTokenizer st = new StringTokenizer(savedString, ",");
Boolean[] savedList = new Boolean[10];
 for (int i = 0; i < 10; i++) {
    savedList[i] = Boolean.valueOf(st.nextToken();
  }

you'r welcome , i use this way because it's simple and do what i want perfectly — Zied R., Mar 08 '14 at 17:33
i am having trouble understanding what happens at the first launch of the application where the preferences are not yet present doesn't it return an error ? — user3368764, Mar 08 '14 at 17:35

score 0 · Answer 3 · edited May 23 '17 at 12:20

Use key names instead of isChk to get value of keys from SharedPreferences because isChk is SharedPreferences name :

keys[i] = settings.getBoolean("keys", false);

Also you are saving all values with same key keys so you only get last value which you have added. to store all values use unique keys like "keys"+i.

For more how we add Array in SharedPreferences see this post:

Save ArrayList to SharedPreferences

sharedpreferences putting an array

3 Answers3

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