MultiSelectListPreference defaultValues not working

Question

I have a project that I am building in Android Studio. I've added the prebuilt preference screen with fragments which compiles and runs fine. I added a MultiSelectListPreference to one of the preference screens which displays fine and stores preference settings. However, the defaultValue is not working whether I add it via Java or XML. I have read the scores of other questions about how to do this. I know how. My question is what could cause it not to work as intended?

pref_general.xml

<MultiSelectListPreference
    android:key="@string/pref_key_starting_addresses"
    android:summary="@string/pref_description_addresses"
    android:title="@string/pref_title_addresses"
    android:entries="@array/empty_array"
    android:entryValues="@array/empty_array" />

PreferenceActivity.java

/**
 * This method autopopulates a MultiSelectListPreference with array values
 * loaded from XML.
 */
private void populateMultiSelectListPreference() {
    List<TypedArray> origins = ResourceHelper.getMultiTypedArray(mContext, "origins");
    CharSequence[] entries = new CharSequence[origins.size()];
    CharSequence[] values = new CharSequence[origins.size()];
    int counter = 0;
    for (TypedArray item : origins) {
        entries[counter] = item.getString(0);
        values[counter] = String.valueOf(counter);
        counter++;
    }

    final MultiSelectListPreference lp = (MultiSelectListPreference) findPreference(getString(R.string.pref_key_starting_addresses));
    lp.setEntries(entries);
    lp.setDefaultValue(values);
    lp.setEntryValues(values);
}

arrays.xml

<string-array name="empty_array" />

<!-- a number of these are used to generate the MultiSelectListPreference
     titles and entry values-->
<array name="origins_0">
    <item>Text used for title</item>
    <item>data 1</item>
    <item>data 2</item>
</array>

I know that everything is working properly because debugging shows that values contains a valid Set and saving preferences works fine. This means that lp.setEntryValues(values) works and that values is a properly formatted Set. However, lp.setDefaultValue(values) has no effect. The checkboxes are all unchecked at first run. My goal is to have them all selected by default.

Yes, I have used the Clean and rerun 'app' command from Android Studio's Run menu between tests. Additionally, I've cleared the app cache manually on the device.

[EDIT]

With suggestions in comments, I have also tried the following modification.

private void populateMultiSelectListPreference() {
    List<TypedArray> origins = ResourceHelper.getMultiTypedArray(mContext, "origins");
    CharSequence[] entries = new CharSequence[origins.size()];
    CharSequence[] values = new CharSequence[origins.size()];
    Set<String> defaults = new HashSet<>();
    int counter = 0;
    for (TypedArray item : origins) {
        entries[counter] = item.getString(0);
        values[counter] = String.valueOf(counter);
        defaults.add(String.valueOf(counter));
        counter++;
    }

    final MultiSelectListPreference lp = (MultiSelectListPreference) findPreference(getString(R.string.pref_key_starting_addresses));
    lp.setEntries(entries);
    lp.setEntryValues(values);
    lp.setDefaultValue(defaults);
}

Answer 1

A quick guess here but I wonder if the reason is just the order you are calling your values, I would set the default values in the last step considering the full list should be initialized first:

final MultiSelectListPreference lp = (MultiSelectListPreference) findPreference(getString(R.string.pref_key_starting_addresses));
lp.setEntries(entries);
lp.setEntryValues(values);
lp.setDefaultValue(values);