導入地址簿聯繫信息，如何處理空字段？

Question

我導入聯繫人信息到一些文本框，但應用程序崩潰，如果有某些方面的任何條目，如電話，電子郵件等

這裏是我的文本框：

First Name 
    Middle Name 
    Last Name 

    Main Phone 
    Mobile Phone 

    Email Address 

    Website 

假設所選聯繫人不會有第二個電話號碼（在這種情況下爲手機），或者沒有該聯繫人的URL條目。該應用程序崩潰。

*ABMutableMultiValueRef phoneMulti = ABRecordCopyValue(person, kABPersonPhoneProperty); 
NSMutableArray *phones = [[NSMutableArray alloc] init]; 
int i; 
for (i = 0; i < ABMultiValueGetCount(phoneMulti); i++) { 
    NSString *aPhone = [(NSString*)ABMultiValueCopyValueAtIndex(phoneMulti, i) autorelease];   
    [phones addObject:aPhone]; 
} 

accountPhone1TextField.text = [phones objectAtIndex:0]; 
accountPhone2TextField.text = [phones objectAtIndex:1]; 
CFRelease(phoneMulti); 
[phones release];* 

或者，如果我試圖從該聯繫人的電子郵件地址，它不存在，這將崩潰：

NSString *anEmail = [(NSString*)ABMultiValueCopyValueAtIndex(emailMulti, i) autorelease]; 
//Variable is not a CFString 

***** UPDATE *****

結束了使用下面的代碼：

ABMutableMultiValueRef emailMulti = ABRecordCopyValue(person, kABPersonEmailProperty); 
NSMutableDictionary *myEmailDict = [NSMutableDictionary dictionaryWithCapacity:ABMultiValueGetCount(emailMulti)]; 
for (CFIndex i = 0; i < ABMultiValueGetCount(emailMulti); i++) { 
    emailLabel = ABAddressBookCopyLocalizedLabel(ABMultiValueCopyLabelAtIndex(emailMulti, i)); 
    email = ABMultiValueCopyValueAtIndex(emailMulti, i); 
    [myEmailDict setObject:(NSString*)email forKey:(NSString*)emailLabel]; 
    CFRelease(email); 
    CFRelease(emailLabel); 
} 

Answer 1

if (phones.count > 0) { 
    accountPhone1TextField.text = [phones objectAtIndex:0]; 
} 
if (phones.count > 1) { 
    accountPhone2TextField.text = [phones objectAtIndex:1]; 
}