我有一个类在 iPhone 应用程序中保存我的用户的联系人列表。

其核心实现如下。

//file Contacts.m
//imports here
    void MyAddressBookExternalChangeCallback (
                                              ABAddressBookRef addressBook,
                                              CFDictionaryRef info,
                                              void *context
                                              )
    {
        NSLog(@"callback called ");
        [[Contacts sharedInstance] refresh];
    }

@implementation Contacts
@synthesize addressBook;

+ (Contacts*)sharedInstance
{
    @synchronized(self)
    {
        if (sharedInstance == nil)
        {
            sharedInstance = [[Contacts alloc] init];
        }
    }
    return sharedInstance;
}

- (void)refresh
{
    ABAddressBookRevert(addressBook); /*refreshing the address book in case of changes*/
   [people release];
    people = (NSArray*)ABAddressBookCopyArrayOfAllPeople(addressBook);

}

- (id)init
{
    if ((self = [super init]))
    {
        sharedInstance = self;
        addressBook = ABAddressBookCreate();;
        people = nil;                                                               
        [self refresh];
        ABAddressBookRegisterExternalChangeCallback (      addressBook,
                                                           MyAddressBookExternalChangeCallback,
                                                          self
                                                          );
    }
    return sharedInstance;
}

在 init 中，我设置了一个外部回调 MyAddressBookExternalChangeCallback 来通知联系人列表的更改。 我遇到的问题是，当我在 iPhone 手机应用程序中添加联系人时，不会调用外部回调(我从未看到 nslog 消息的结果)。

我做错了什么？

添加注释:如果我这样做，甚至更陌生

ABAddressBookRevert(addressBook);

每次我的应用程序出现在前面并且通讯录被修改时，回调就会被调用。

最佳答案

我在我的 iPhone 上测试了这个并验证回调被调用:

联系人.h:

#import <Foundation/Foundation.h>
#import <AddressBook/AddressBook.h>

@interface Contacts : NSObject
{
    ABAddressBookRef addressBook;
    NSArray *people;
}

+ (Contacts*)sharedInstance;
- (void)refresh;

void MyAddressBookExternalChangeCallback (
                                          ABAddressBookRef addressBook,
                                          CFDictionaryRef info,
                                          void *context
                                          );

@end

联系人.m:

#import "Contacts.h"

void MyAddressBookExternalChangeCallback (
                                          ABAddressBookRef addressBook,
                                          CFDictionaryRef info,
                                          void *context
                                          )
{
    NSLog(@"callback called ");
    [[Contacts sharedInstance] refresh];
}

@implementation Contacts

+ (Contacts*)sharedInstance
{
    static Contacts *sharedInstance = nil;

    @synchronized(self)
    {
        if (sharedInstance == nil)
        {
            sharedInstance = [[Contacts alloc] init];
        }
    }
    return sharedInstance;
}

- (void)refresh
{
    ABAddressBookRevert(addressBook); /*refreshing the address book in case of changes*/
    [people release];
    people = (NSArray*)ABAddressBookCopyArrayOfAllPeople(addressBook);

}

- (id)init
{
    if ((self = [super init]))
    {
        //sharedInstance = self;
        addressBook = ABAddressBookCreate();
        people = nil;                                                               
        [self refresh];
        ABAddressBookRegisterExternalChangeCallback (addressBook,
                                                     MyAddressBookExternalChangeCallback,
                                                     self
                                                     );
    }
    return self;
}

@end

关于objective-c - iOS 中未调用 ABAddressBook 外部回调，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9112671/