调用[myString release]不会减少[myString retainCount] [英] calling [myString release] does NOT decrement [myString retainCount]

问题描述

我有以下情况，这似乎导致我的iPad应用程序泄漏内存。

I have the following situation, which seems to cause my iPad application to leak memory.

我有一个带字符串属性的类......

I have a class with a string property...

@property(nonatomic,retain) NSString * synopsis;

我从一些HTTP响应中设置字符串属性，来自JSON或XML响应。

I set the string property from some HTTP response, either from JSON or XML response.

此时，概要对象的保留计数为1.

At that point the retain count of the synopsis object is 1.

但我有这种情况：

我将概要保存到本地sqlite数据库，然后我想从内存中释放它，但我有奇怪的情况，调用 [概要发布] 从我的对象中不会将保留计数减少到0。

I save the synopsis to a local sqlite database, and then I want to release it from memory, but I have the situation where strangely, calling [synopsis release] from within my object does not decrement the retain count to 0.

(void) save
{
  NSLog(@"synopsis before save retainCount=%d",[synopsis retainCount]);
  [self saveToDb:synopsis withKey:@"synopsis"];
  NSLog(@"synopsis after save retainCount=%d",[synopsis retainCount]);
  [synopsis release];
  NSLog(@"synopsis after release retainCount=%d",[synopsis retainCount]);
  synopsis=nil;
}

在控制台中我得到：

synopsis before save retainCount=1

synopsis after save retainCount=1

synopsis after release retainCount=1

这怎么可能？我在模拟器或设备上运行相同的结果。

How can this be possible? I get the same result running in simulator or on the device.

推荐答案

不要依赖 RETAINCOUNT ！

对于人类来说，它不是对象所有权的准确度量。你不知道框架中幕后的保留和发布是什么。

Cocoa中的内存管理很简单：

Memory management in Cocoa is simple:

1. 如果你 alloc / init 或复制一个对象，请确保调用 release 在某些时候。


2. 如果你想保留一个物体，请拨打保留 - 但要确保在某些时候也要打电话给发布。

1. If you alloc/init or copy an object, make sure you call release on it at some point.
2. If you want to keep an object around, call retain -- but make sure to call release at some point, too.

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