Question

I’m writing a custom addressbook app in ios and I use a singleton addressbookRef.

Here is my operation steps:

+ (ABAddressBookRef) sharedAddressBook
{
    static ABAddressBookRef ref = nil;
    if ( ref == nil )
    {
        ref = ABAddressBookCreate();
    }

    return ( ref );
}

step1:
Open my addressbook app

    ABAddressBookRef addressBook = [ABAddressBook sharedAddressBook];
    ABRecordRef person = ABAddressBookGetPersonWithRecordID( addressBook, 83 );
    NSString* name= ABRecordCopyValue(person,kABPersonFirstNameProperty);
    NSLog(@"%@",name);

console print “aaa”.

step2:

quit my app(enterBackground, not kill), change the “aaa” person name to “bbb” by using the system dialer.

step3:

open my app(enterForeground), do the same thing

ABAddressBookRef addressBook = [ABAddressBook sharedAddressBook];
ABRecordRef person = ABAddressBookGetPersonWithRecordID( addressBook, 83 );
NSString* name= ABRecordCopyValue(person,kABPersonFirstNameProperty);
NSLog(@"%@",name);

console print “aaa”.

My question is

1.Why the console print “aaa”, not “bbb” when used the old addressBookRef? When i change the [ABAddressBook sharedAddressBook] to ABAddressBookCreate(), everything seems to be ok. Why the old addressBookRef can not keep up-to-date?

2.Should I need do ABAddressBookCreate() at enterForeground everytime?

3.is the recordID changed when I edit the person info? I suspect.

Answer 1

static void _ExternalChangeCallback( ABAddressBookRef bookRef, CFDictionaryRef info, void * context )
{
    HMAddressBook * hmAddressBook = (HMAddressBook *)context;

    [hmAddressBook _resetSharedRef];
}

@implementation HMAddressBook
@synthesize addressBookRef = _ref;

+ (HMAddressBook *)sharedAddressBook
{
    static HMAddressBook * volatile __shared = nil;

    if ( __shared == nil )
    {
        HMAddressBook * tmp = [[HMAddressBook alloc] init];
        if ( OSAtomicCompareAndSwapPtr(nil, tmp, (void * volatile *)&__shared) == false )
            [tmp release];
    }

    return ( __shared );
}


- (void)_resetSharedRef
{
    if (_ref != NULL)
    {
        ABAddressBookUnregisterExternalChangeCallback(_ref, _ExternalChangeCallback, self);
        CFRelease(_ref);
    }
    _ref = ABAddressBookCreate();
    ABAddressBookRegisterExternalChangeCallback(_ref, _ExternalChangeCallback, self);

    if(_delegate && [_delegate respondsToSelector:@selector(addressBookDidResetSharedRef:)])
    {
        [_delegate addressBookDidResetSharedRef:self];
    }

}
- (void)addressBookDidResetSharedRef:(HMAddressBook *)addressBook
{
    NSLog(@"addressBookDidReset");    
    [self reloadAddressBookData_async:^(BOOL finished) {
        [completionBlock reloadData];
    }];

}

Now I reloadAddressbook async when _ExternalChangeCallback! reloadAddressbook need reallocate all the person(wrapped) instances, but no need to recreate it’s cache data.