从NSString调试EXC_BAD_ACCESS

Question

我的控制台中有一条EXC_BAD_ACCESS消息.我在这个网站上读到了环境变量NSZombieEnabled和MallocStackLoggingNoCompact .我创建了我的环境变量:NSZombieEnabled = YES 和MallocStackLoggingNoCompact = 1.在控制台中,我看到了

2010-03-01 19:13:46.924 CruzNomad [7952:207]*** - [CFString stringByAddingPercentEscapesUsingEncoding:]:发送到解除分配的实例0x58448e0的消息

然后在(gdb)提示符下,我做了信息malloc-history 0x58448e0,它给了我:

Alloc: Block address: 0x058448e0 length: 64
Stack - pthread: 0xa0b33500 number of frames: 25
    0: 0x98e089bc in malloc_zone_malloc
    1: 0x21516aa in _CFRuntimeCreateInstance
    2: 0x2152bf8 in __CFStringCreateImmutableFunnel3
    3: 0x21567d9 in CFStringCreateCopy
    4: 0x21742fc in _CFStringCreateWithFormatAndArgumentsAux
    5: 0xdb546 in -[NSPlaceholderString initWithFormat:locale:arguments:]
    6: 0xdb4d8 in +[NSString stringWithFormat:]
    7: 0x23aa3 in -[BuisnessCardViewController viewDidLoad] at /Users/.../Classes/BuisnessCardViewController.m:85
    8: 0x3d6796 in -[UIViewController view]
    9: 0x347b4 in -[gm_menuViewController btn5_Pressed:] at /Users/.../Classes/menuViewController.m:535
   10: 0x357459 in -[UIApplication sendAction:to:from:forEvent:]
   11: 0x3baba2 in -[UIControl sendAction:to:forEvent:]
   12: 0x3bcdc3 in -[UIControl(Internal) _sendActionsForEvents:withEvent:]
   13: 0x3bbb0f in -[UIControl touchesEnded:withEvent:]
   14: 0x370e33 in -[UIWindow _sendTouchesForEvent:]
   15: 0x35a81c in -[UIApplication sendEvent:]
   16: 0x3610b5 in _UIApplicationHandleEvent
   17: 0x2984ed1 in PurpleEventCallback
   18: 0x2197b80 in CFRunLoopRunSpecific
   19: 0x2196c48 in CFRunLoopRunInMode
   20: 0x298378d in GSEventRunModal
   21: 0x2983852 in GSEventRun
   22: 0x362003 in UIApplicationMain
   23: 0x2c8c in main at /Users/.../source/main.m:14
   24: 0x2bfa in start

第7行说问题出现在BuisnessCardViewController.m的第85行.那条线在这里:

fullAddress = [NSString stringWithFormat:@"%@ %@", fullAddress, myString];

我将附加fullAddress和myString的内容并将其存储在fullAddress中.

如果我正确地解释了这一点,那么看起来在此行之后,fullAddress被释放.当我删除断点并将鼠标悬停在变量上时,其值显示"超出范围".

fullAddress稍后在此方法中工作.我使用它发送给谷歌,以便在相同方法的第164行中进行反向地理编码.

NSString    *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps/geo?q=%@&output=csv", [fullAddress stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

即使在这里,它也说"超出范围".我很难过......任何建议？

谢谢!

托马斯

Answer 1

在大多数情况下，当您不保留对象属性并在其他方法中向其发送延迟消息时，就会发生这种情况。

因此，在初始化一些字符串的地方尝试：

[fullAddress retain];

或者

[myString retain];

取决于在其他方法中初始化哪一个。