You should probably write a custom PeoplePickerViewController since you'll never have enough control over Apple's default controller.
Anyway, as for your current problem, here's what you need to do:
Declare three new properties (use appropriate declarations based on if you are using ARC or not - I'm assuming no ARC)
@property (nonatomic, assign) ABPeoplePickerNavigationController *peoplePicker;
@property (nonatomic, assign) UIViewController *peoplePickerRootViewController;
@property (nonatomic, copy) NSString *currentSearchString;
Now, when you display people picker, add these lines:
// save people picker when displaying
self.peoplePicker = [[[ABPeoplePickerNavigationController alloc] init] autorelease];
// save it's top view controller
self.peoplePickerRootViewController = self.peoplePicker.topViewController;
// need to see when view controller is shown/hidden - viewWillAppear:/viewWillDisappear: won't work so don't bother with it.
self.peoplePicker.delegate = self;
Now, we'll save search string just before pushing person view:
- (BOOL)peoplePickerNavigationController:(ABPeoplePickerNavigationController *)peoplePicker shouldContinueAfterSelectingPerson:(ABRecordRef)person
{
self.currentSearchString = nil;
if ([self.peoplePickerRootViewController.searchDisplayController isActive])
{
self.currentSearchString = self.peoplePickerRootViewController.searchDisplayController.searchBar.text;
}
// other stuff...
Obviously, implement UINavigationControllerDelegate in this class. When the root view comes back into view, we will force display search results view. Here's the implementation for navigationController:willShowViewController:animated:
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
if (navigationController == self.peoplePicker)
{
if (viewController == self.peoplePickerRootViewController)
{
if (self.currentSearchString)
{
[self.peoplePickerRootViewController.searchDisplayController setActive: YES];
self.peoplePickerRootViewController.searchDisplayController.searchBar.text = self.currentSearchString;
[self.peoplePickerRootViewController.searchDisplayController.searchBar becomeFirstResponder];
}
self.currentSearchString = nil;
}
}
}
Don't forget to release currentSearchString in dealloc if not using ARC.
Small caveat: There is a slight flicker when you select a person when ABPeoplePickerNavigationController is trying to hide the search results view.