android adding MultiSelectListPreference

Question

I am trying to implement android jetpack preference for my settings screen. everything is working good, when I click on MultiSelectListPreference, it shows the list of entries, but I have few questions,

1. why can't the entryValues be a integer-array? (string-array is working fine)
2. how to set default values? for eg: I want to set the second and third entry to be checked by default in the beginning.

here is a part of my pref.xml file

...
app:entries="@array/res_entries"
app:entryValues="@array/res_id_values"
app:defaultValue="@array/res_def_values" //this line is not working
...

If I set res_id_values in arrays.xml file to be a integer-array, then app is crashing.

My settingsFragment class extends PreferenceFragmentCompat and override onCreatePreferences and in it, I have written

setPreferencesFromResource(R.xml.pref.xml, rootkey)

EDIT

My res_entries array :

<string-array name="res_entries">
  <item>apple</item>
  <item>Mango</item>
  <item>Guava</item>
</string-array>

My res_id_values array :

<string-array name="res_id_values">
  <item>1</item>
  <item>2</item>
  <item>12</item>
</string-array>

My res_def_values array :

<string-array name="res_def_values">
  <item>true</item>
  <item>false</item>
  <item>true</item>
</string-array>

Answer 1

So finally, I solved it. All thanks to @CommonsWare .

answer to my first question is that, we cannot use integer-array. Use a string array and store integer values in it. later when you get it, use Integer.parseInt().

now coming to second question, to store default value(let's say you want second and third item to be checked by default), use res_id_values in res_def_values. Don't use true/false or 0/1 like me.

eg: if in above question, If I want apple and guava to be checked by default, then my res_def_values will look like this:

<string-array name="res_def_values">
  <item>1</item>
  <item>12</item>
</string-array>