How to get national holidays of selected country

The CalendarProvider documentation states that it only provides the current user's calendar information.

The Calendar Provider is a repository for a user's calendar events. The Calendar Provider API allows you to perform query, insert, update, and delete operations on calendars, events, attendees, reminders, and so on.

You will need to access a third-party API (this one, for example) and load that information into your application.

Problem solved by using Google Calendar API V3. The idea I found from this post. The holiday can get from default holiday calendar of google.

The ID list of default holiday calendar can be found here, support to 40 country.

A piece of code that handle permission and get holiday list:-

com.google.api.services.calendar.Calendar client = null;
        credential = GoogleAccountCredential.usingOAuth2(mContext, CalendarScopes.CALENDAR);
        credential.setSelectedAccountName(mList.get(0));
        client = getCalendarService(credential);
        do {
            com.google.api.services.calendar.model.Events events;
            events = client.events().list("en.usa#[email protected]").setPageToken(pageToken).execute();
            onHolidayChecked(events.getItems()); //result return here (events.getItems())
            pageToken = events.getNextPageToken();
        } while (pageToken != null);

private com.google.api.services.calendar.Calendar getCalendarService(GoogleAccountCredential credential) {
    return new com.google.api.services.calendar.Calendar.Builder(AndroidHttp.newCompatibleTransport(), new GsonFactory(), credential).build();
}