给定线程 1 exc_bad_access（代码=2 地址=0x8），Xcode 不断崩溃
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Xcode continuously crashes given thread 1 exc_bad_access (code=2 address=0x8)
提问by mhamer13
after researching this error i have noticed it is code specific but any project i attempt to make, load, etc keeps giving me the same error and is always citing different parts of the code with this error message but because of the initial programs i setup, that have the exact default code nothing less nothing more and still receive the same errors i wouldn't see how adding my error log could help. Note this error occurs when using sprite kit in Xcode 5 and am running this on os x 10.8.5 thanks ahead of time for your patience, insight and hopefully an answer.
在研究了这个错误之后，我注意到它是特定于代码的，但是我尝试制作、加载等的任何项目都会给我同样的错误，并且总是用这个错误消息引用代码的不同部分，但是由于我设置的初始程序，具有确切的默认代码，仅此而已，并且仍然收到相同的错误，我看不出添加错误日志有何帮助。请注意，在 Xcode 5 中使用 sprite kit 并在 os x 10.8.5 上运行此错误时会发生此错误，提前感谢您的耐心、洞察力并希望得到答案。
回答by Jasper Blues
exc_bad_access is usually caused by what's known as a dangling pointer - accessing an object that has already been deallocated.
exc_bad_access 通常是由所谓的悬空指针引起的——访问一个已经被释放的对象。
To debug this, enable zombie objects by either:
要对此进行调试，请通过以下任一方式启用僵尸对象：
- Xcode : Edit the scheme and choose the 'Enabled Zombies' checkbox
- Xcode：编辑方案并选择“启用僵尸”复选框
- AppCode : Edit the run configuration and set the environment variable NS_ZOMBIE_ENABLED=YES
- AppCode : 编辑运行配置并设置环境变量 NS_ZOMBIE_ENABLED=YES
Spend some time to learn the Objective-C reference counting memory model - retains, releases, retain-cycles and autorelease pools.
花一些时间学习 Objective-C 引用计数内存模型 - 保留、释放、保留循环和自动释放池。
You need to ensure that your object is being retained for as long as its being used. In ARC (Automatic Reference Counting - the default for iOS) this usually means setting a property or ivar for any object that will be used accross multiple classes - designating one object as the 'owner' of this object. It will then be deallocated along with the object that 'owns' it.
您需要确保您的对象在使用期间一直保留。在 ARC（自动引用计数 - iOS 的默认设置）中，这通常意味着为将在多个类中使用的任何对象设置属性或 ivar - 将一个对象指定为该对象的“所有者”。然后它将与“拥有”它的对象一起被释放。
A good way to get an understanding of the Objective-C memory model and the way ARC works, is to try using manual memory management on a pet project (something with at least 2 or 3 view controllers). Once you're comfortable with manual-memory management, ARC will be super-easy, as well as save you time, typing and prevent forgetting to release an allocated object. Most/all Objective-C fundamentals books will cover memory management. (I've forgotten the name now of the one that I read).
了解 Objective-C 内存模型和 ARC 工作方式的一个好方法是尝试在宠物项目（至少有 2 或 3 个视图控制器的项目）上使用手动内存管理。一旦您对手动内存管理感到满意，ARC 将变得非常简单，并且可以节省您的时间、打字和防止忘记释放分配的对象。大多数/所有 Objective-C 基础书籍都将涵盖内存管理。（我现在忘记了我读过的那个人的名字）。
A Common Cause
一个共同的原因
Let's say you have a UIViewController and a View that you'd like to present from within your current view controller. . . its allocated as follows:
假设您有一个 UIViewController 和一个想要从当前视图控制器中呈现的视图。. . 其分配如下：
UIViewController* anotherController = [UIViewController make];
[self.view addSubView anotherController.view];
'anotherController' will now be deallocated because its no longer used. If anotherController.view has unsafe_unretained references to anotherController it will cause an exc_bad_access.
'anotherController' 现在将被释放，因为它不再使用。如果 anotherController.view 有对 anotherController 的 unsafe_unretained 引用，它将导致 exc_bad_access。
Infinite Recursion:
无限递归：
Another cause of EXC_BAD_ACCESS is infinite recurssion, which can be debugged by adding some log statements - it will soon become apparent then!
EXC_BAD_ACCESS 的另一个原因是无限递归，可以通过添加一些日志语句来调试——这很快就会变得明显！
