SharedPreferences is being reset every time the app started

Question

I have this code on my MainActivity.java:

  SharedPreferences ids = getSharedPreferences(AddedIds, Context.MODE_PRIVATE);
  SharedPrefernces.Editor editor = ids.edit();
    if (ids.getStringSet(AddedIds, id).isEmpty()) {
        Set<String> id = new HashSet<String>();
        editor.putStringSet(AddedIds, id);
        editor.apply();
    }

This code is checking whether the Set<String> is existing in the SharedPreferences. If not, then it adds the Set<String> to the SharedPreferences.

The problem is that the code is being activated whenever I open the app, althrough it exist in the SharedPreferences.

Answer 1

I believe id is the string that you are searching in stringset. Change your code to below.

Set<String> set = ids.getStringSet(AddedIds, null);
    Boolean keyfound = false;
    if ( set != null){
        for (String key : set){
            if(key.equals(id)){
                keyfound = true;
                break;
            }
        }
        if(!keyfound){
            set.add(id);
            editor.putStringSet(AddedIds, set);
            editor.apply();
        }
    }
    else{
        set = new HashSet<String>();
        set.add(id);
        editor.putStringSet(AddedIds, set);
        editor.apply();
    }