在Swift中使用委托模式重构CNContactPicker UI代码

protocol ContactPickerDelegate: AnyObject {
    func contactPickerDidSelectContact(_ contact: CNContact)
    func contactPickerDidCancel()
}

class ContactPickerViewController: UIViewController {
    weak var delegate: ContactPickerDelegate?

    func showContactPicker() {
        let contactPicker = CNContactPickerViewController()
        contactPicker.delegate = self
        // 显示联系人选择器
        // ...
    }
}

extension ContactPickerViewController: CNContactPickerDelegate {
    func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
        delegate?.contactPickerDidSelectContact(contact)
    }

    func contactPickerDidCancel(_ picker: CNContactPickerViewController) {
        delegate?.contactPickerDidCancel()
    }
}

class MainViewController: UIViewController {
    // ...

    func showContactPicker() {
        let contactPicker = ContactPickerViewController()
        contactPicker.delegate = self
        contactPicker.showContactPicker()
    }
}

extension MainViewController: ContactPickerDelegate {
    func contactPickerDidSelectContact(_ contact: CNContact) {
        // 处理选择的联系人
    }

    func contactPickerDidCancel() {
        // 处理取消选择
    }
}