Question

我正在尝试获取联系人的电子邮件地址和电子邮件地址的类型（工作/家庭）。这是我写的代码

//Assume that 'personRef' of type ABRecordRef is available
....
ABMultiValueRef emailRef = ABRecordCopyValue(personRef, kABPersonEmailProperty);
NSMutableArray *emailAddresses = nil, *emailAddressLabels = nil;
int ctr = ABMultiValueGetCount(emailRef);
if(ctr!=0) {
    emailAddresses = [[NSMutableArray alloc]init];
    emailAddressLabels = [[NSMutableArray alloc]init];
    for(int i=0; i<ctr; i++) {
        NSString *eId = (__bridge_transfer NSString*)ABMultiValueCopyValueAtIndex(emailRef, i);
        [emailAddresses addObject:eId];
        CFStringRef label = ABMultiValueCopyLabelAtIndex (emailRef, i);
        if(label!=NULL) {
            NSString *eType = (__bridge_transfer NSString*)ABAddressBookCopyLocalizedLabel(label);
            if([eType isEqualToString:@""]) {
                [emailAddressLabels addObject:@"Email"];
            } else {
                [emailAddressLabels addObject:eType];
            }
            CFRelease(label);
        }
    }
}

代码在CFRelease（标签）崩溃，但为了防止内存泄漏，我应该这样做。当我尝试以下

NSString *eType = (__bridge_transfer NSString*) ABAddressBookCopyLocalizedLabel(ABMultiValueCopyLabelAtIndex (emailRef, i));

我从ARC收到以下警告

1. Call to function 'ABMultiValueCopyLabelAtIndex' returns a Core Foundation object with a +1 retain count
2. Object leaked: allocated object is not referenced later in this execution path and has a retain count of +1

现在我的问题是，如何进行嵌套__bridge_transfer调用？

Answer 1

NSString *eType = (__bridge_transfer NSString*)
    ABAddressBookCopyLocalizedLabel(
        ABMultiValueCopyLabelAtIndex (emailRef, i) /* <-- this object is leaked */
    );

此代码无效，因为您在此处泄漏了标签（我认为这是您的观点？）。

你应该在Instruments NSZombie工具下运行该代码，它将跟踪所有保留/释放，你将知道发生了什么，因为坦率地说，看看代码，我不明白为什么它是错的。

使用ARC嵌套桥接传输调用

1 个答案: