Question

我有以下代码：

@implementation SendMapViewController

NSMutableArray *emails;

在这个方法中，我创建了电子邮件数组，并添加了一些NSStrings：

- (BOOL) peoplePickerNavigationController: (ABPeoplePickerNavigationController *)peoplePicker
       shouldContinueAfterSelectingPerson: (ABRecordRef)person {

    ABMultiValueRef emailInfo = ABRecordCopyValue(person, kABPersonEmailProperty);

    NSUInteger emailCount = ABMultiValueGetCount(emailInfo);

    if (emailCount > 1) {

        UIActionSheet *emailsAlert = [[UIActionSheet alloc]
                                      initWithTitle:@"Select an email"
                                      delegate:self 
                                      cancelButtonTitle:nil
                                      destructiveButtonTitle:nil
                                      otherButtonTitles:nil];

        emails = [NSMutableArray arrayWithCapacity: emailCount];

        for (NSUInteger i = 0; i < emailCount; i++) {
            NSString *emailFromContact = (NSString *)ABMultiValueCopyValueAtIndex(emailInfo, i);

            [emails addObject: emailFromContact];

            [emailsAlert addButtonWithTitle:emailFromContact];

            [emailFromContact release];
        }

        [emailsAlert addButtonWithTitle:@"Cancel"];

        [emailsAlert showInView:self.view];

        [emailsAlert release];
    }
    else {
        ...
    }

    CFRelease(emailInfo);

    [self dismissModalViewControllerAnimated:YES];

    return NO;
}

正如您在代码中看到的，如果我展示了多个电子邮件和UIActionSheet。当用户点击代表和发送电子邮件的按钮时，我想执行以下代码：

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {

    if ([emails count] >= buttonIndex) {
        NSString *contactEmail = (NSString *)[emails objectAtIndex:buttonIndex];

        ...
    }
}

但是电子邮件阵列没有收到任何电子邮件。我做错了什么？

我正在为iPhone开发。

Answer 1

当你不看时，你的emails物体可能是自动释放的。替换行：

emails = [NSMutableArray arrayWithCapacity: emailCount];

使用：

[emails release];
emails = [[NSMutableArray alloc] initWithCapacity:emailCount];

以便emails不会自动释放。（记住，你拥有init返回的任何内容，但是方便构造函数（如arrayWithCapacity:返回的对象会自动释放。）

最佳解决方案是声明属性：

@property (retain) NSMutableArray* emails;

然后使用：

[self setEmails:[NSMutableArray arrayWithCapacity: emailCount]];

使用属性的第二种方法确实是最好的，因为它更灵活，更清晰。这样，属性的访问者（使用@synthesize创建）将为您处理调用retain。

从UIActionSheet委托访问ViewController的变量

1 个答案: