我看过几次这个崩溃报告。极其随意和稀有，看不懂。我所做的只是使用以下代码呈现模态视图 Controller

ComposeController *newcontrol = [[ComposeController alloc]initWithMode:1 withNIB:@"ComposeController"];
newcontrol.delegate = self;

UINavigationController  *holder = [[UINavigationController alloc] initWithRootViewController:newcontrol];
[self presentViewController:holder animated:YES completion:NULL];

不知何故，这完全是随机的:

OS Version:      iPhone OS 6.1 (10B143)
Report Version:  104

Exception Type:  SIGSEGV
Exception Codes: SEGV_ACCERR at 0x9
Crashed Thread:  0

Thread 0 Crashed:
0   libobjc.A.dylib                     0x3b25c5d0 objc_msgSend + 16
1   CoreFoundation                      0x334ba73f -[__NSPlaceholderArray initWithObjects:count:] + 271
2   CoreFoundation                      0x334bae09 +[NSArray arrayWithObject:] + 45
3   UIKit                               0x353e80ab -[UIWindow _rotationViewControllers] + 51
4   UIKit                               0x353e7fe3 -[UIViewController viewControllerForRotation] + 91
5   UIKit                               0x353e7f39 -[UIViewController _visibleView] + 97
6   UIKit                               0x3546c05b -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:] + 2483
7   UIKit                               0x3546afab -[UIViewController presentViewController:withTransition:completion:] + 3399
8   MyApp                               0x00046e97 -[Inbox composeHit] (Inbox.m:207)

最佳答案

我一直有同样的问题。这似乎是由于我从弹出窗口中呈现模态视图 Controller 这一事实引起的，它没有经过很好的测试并触发了 Apple 代码中的错误。错误是 UIKit 保留了对我的 View Controller 的未保留引用，该引用已经被解除和释放，因此稍后会命中该引用。我的解决方法是要么避免从弹出窗口中呈现模态 VC，要么自己无限期地保留所有此类 VC(在成员变量或类似变量中)。

下面是血淋淋的细节。

这是我用来触发问题的代码。

-(void) handlePinchFromCell:(AMPSupportingPhotoCell*) cell
{
    UIViewController * vc = [[UIViewController alloc] init]; // UIViewController #0
    [self presentViewController:vc animated:YES completion:nil];
    [self performSelector:@selector(dismiss:) withObject:vc afterDelay:2];
}

-(void) dismiss:(UIViewController*)vc
{
    [self dismissViewControllerAnimated:YES completion:^(){NSLog(@"-------");}];
}

此代码是 UIViewController #1 的一部分，它位于 UIPopoverController 内，它从另一个 UIViewController #2 弹出，它本身是从另一个 View UIViewController #3 呈现的。崩溃发生在弹出窗口关闭后， Controller #2 id 被关闭。

如果我启用 Zombies，我会得到相同的堆栈跟踪，但有一条消息:

2013-03-13 20:04:24.681 Mercury[16698:19d03] handlePinchFromCell: a225710
2013-03-13 20:04:27.083 Mercury[16698:19d03] -------
2013-03-13 20:04:31.606 Mercury[16698:19d03] *** -[UIViewController retain]: message sent to deallocated instance 0xa225710

因此，请注意 VC#0 已分配、显示、2 秒后解除、释放，但在 Apple 代码的某处仍然存在对它的悬空引用。当弹出窗口关闭并且 VC#2 被关闭时，整个事情都会崩溃，试图访问已释放的 VC。我相当确定这是Apple的错误。我还猜想它与从弹出窗口中呈现 VC 有关，所以如果你远离它，或者自己保留 VC，你应该没问题。

同一问题的另一个堆栈跟踪是这样的。如果上面的代码运行两次，就会发生这种情况:

2013-03-13 20:12:53.883 Mercury[16735:19d03] handlePinchFromCell: 16d54da0
2013-03-13 20:12:56.285 Mercury[16735:19d03] -------
2013-03-13 20:13:03.481 Mercury[16735:19d03] handlePinchFromCell: a2565f0
2013-03-13 20:13:03.481 Mercury[16735:19d03] *** -[UIViewController isKindOfClass:]: message sent to deallocated instance 0x16d54da0
(lldb) bt
* thread #1: tid = 0x1f03, 0x017f8a97 CoreFoundation`___forwarding___ + 295, stop reason = EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0)
    frame #0: 0x017f8a97 CoreFoundation`___forwarding___ + 295
    frame #1: 0x017f894e CoreFoundation`_CF_forwarding_prep_0 + 14
    frame #2: 0x00c42f90 UIKit`-[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:] + 907
    frame #3: 0x00a40ee3 UIKit`-[UIViewController presentViewController:withTransition:completion:] + 4521
    frame #4: 0x00a41167 UIKit`-[UIViewController presentViewController:animated:completion:] + 112
    frame #5: 0x0006c32d Mercury`-[AMPSupportingPhotosViewController handlePinchFromCell:](self=0x16d55360, _cmd=0x0007a64a, cell=0x0a22a2a0) + 205 at AMPSupportingPhotosViewController.m:184
    frame #6: 0x015336b0 libobjc.A.dylib`-[NSObject performSelector:withObject:] + 70
    frame #7: 0x0006f317 Mercury`-[AMPSupportingPhotoCell handlePinch:](self=0x0a22a2a0, _cmd=0x00efb0db, sender=0x0a2504a0) + 215 at AMPSupportingPhotoCell.m:53
    frame #8: 0x00c2185a UIKit`_UIGestureRecognizerSendActions + 139

关于ios - 呈现模态 UIViewController 时发生奇怪的崩溃，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14967840/