Apple的CurrentAddress示例中的MKReverseGeocoder自动释放/释放问题 [英] MKReverseGeocoder autorelease/release question in Apple's CurrentAddress sample

问题描述

我正在查看直接从 CurrentAddress示例可在Apple网站上找到:

I am looking at this code lifted straight from the MapViewController.m file in the CurrentAddress sample available on Apple's web site:

- (void)dealloc
{
    [reverseGeocoder release];
    [mapView release];
    [getAddressButton release];

    [super dealloc];
}

- (IBAction)reverseGeocodeCurrentLocation
{
    self.reverseGeocoder =
        [[[MKReverseGeocoder alloc] initWithCoordinate:mapView.userLocation.location.coordinate] autorelease];
    reverseGeocoder.delegate = self;
    [reverseGeocoder start];
}

我想知道分配对象时自动释放的功能是什么. (reverseGeocoder是MapViewController类中的一个带有保留属性的ivar.)在我的应用程序中，我有与此类似的代码，并且无论哪种方式都可以工作.

I am wondering what the function is of the autorelease when allocating the object. (The reverseGeocoder is an ivar in the MapViewController class set up with the retain property.) I have code similar to this in my application, and it seems to work either way.

推荐答案

设置您的reverseGeocoder属性会增加保留计数(+1)，但是由于您要使用alloc + init(+ 1)，您需要autorelease(-1)，以免最后保留2个计数.

Setting your reverseGeocoder property increments the retain count (+1), but since you're creating the object with alloc+init (+1), you need to autorelease (-1) so that you do not end up with a 2 retain count.

无论哪种方式都可以工作，唯一的区别是，当您执行不 autorelease时，会泄漏.

It does work either way, the only difference is that when you do not autorelease, you leak.

reverseGeocoder是一个ivar

The reverseGeocoder is an ivar

确实可以，但是请注意，当您使用self.reverseGeocoder表单时，并不是直接访问ivar，而是调用相关的setReverseGeocoder:函数，该函数由您自己编写或@由编译器合成.

It sure is, but note that when you're using the self.reverseGeocoder form, you're not accessing the ivar directly - instead, you're calling the relevant setReverseGeocoder: function, that is either written by yourself or @synthesized by the compiler.

请参阅: http://developer. apple.com/library/mac/#documentation/cocoa/conceptual/MemoryMgmt/MemoryMgmt.html

并且: 为声明的属性合成了什么等效代码?

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