iOS - contacts enable/disable ( privacy setting) changes reflection same as WhatsApp?

Question

I am working on a chat application same as whatsapp. So I need same functionality when user disable/enable contact access (privacy setting) for my app. If the user disable or enable the contact in app setting. How can I be notify in the app. I need to keep track when user changes enable/disable contact settings (privacy setting). So i do reflect changes on each event in My App. And if anyone knows how whatsapp doing this.

Given below is the screenshots of whatsapp.

Case 1.Has Contact Access

Case 2 Don't Have Contact Access

Answer 1

每次用户启动应用时，您都可以使用以下代码检查应用是否仍具有联系人权限：

  #import <AddressBookUI/AddressBookUI.h>


- (void)applicationWillEnterForeground:(UIApplication *)application {

  ABAddressBookRef addressBookRef = ABAddressBookCreateWithOptions(NULL, NULL);

  if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
    ABAddressBookRequestAccessWithCompletion(addressBookRef, ^(bool granted, CFErrorRef error) {
      if (granted) {
          // First time access has been granted
         // Show 4 Tabs
      } else {
          // User denied access
          // Show 3 Tabs
      }
    });
  }
  else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
    // The user has previously given access, add the contact
    // Show 4 Tabs

  }
  else {
    // The user has denied access
    // Show only 3 Tabs
  }

}

Answer 2

根据苹果公司的网站（在页面中间向下滚动到隐私），必须先授予对地址簿的访问权限，然后才能以编程方式进行访问。这就是我最终要做的事情 -

#import <AddressBookUI/AddressBookUI.h>

- (BOOL)isContactsFetchingAccessibleOrNot {
  // Request authorization to Address Book
  ABAddressBookRef addressBookRef = ABAddressBookCreateWithOptions(NULL, NULL);

  if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
    ABAddressBookRequestAccessWithCompletion(addressBookRef, ^(bool granted, CFErrorRef error) {
      if (granted) {
          // First time access has been granted, add the contact
          //do something
      } else {
          // User denied access
          // Display an alert telling user the contact could not be added
      }
    });
  }
  else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
    // The user has previously given access, add the contact
    //do something
  }
  else {
    // The user has previously denied access
    // Send an alert telling user to change privacy setting in settings app
  }
}

当app从后台到前台时，您也可以调用此方法。