UIActionSheet坏访问，UIPresentationController僵尸

Question

在iOS 8中测试应用程序时，ActionSheet的访问权限一直很差。(Xcode 6 beta 2，iOS 8模拟器)

这里有一个相关的帖子：UIActionSheet crash in iOS8beta

仪器确实能捕捉到与UIPresentationController相关的僵尸。我不确定我读的是否正确，但似乎保留数从6下降到-1。

下面是完整的日志：

Event Type  ∆ RefCt RefCt   Timestamp   Responsible Library Responsible Caller
0   Malloc  +1  1   00:14.487.023   UIKit   UINibDecoderDecodeObjectForValue
1   Retain  +1  2   00:14.493.979   UIKit   -[UIRuntimeConnection initWithCoder:]
2   Retain  +1  3   00:14.494.009   UIKit   -[UIRuntimeConnection initWithCoder:]
3   Retain  +1  4   00:14.494.069   UIKit   UINibDecoderDecodeObjectForValue
4   Retain  +1  5   00:14.494.089   UIKit   UINibDecoderDecodeObjectForValue
5   Retain  +1  6   00:14.494.190   Foundation  _NSSetUsingKeyValueSetter
6   Retain  +1  7   00:14.494.257   UIKit   -[UINib instantiateWithOwner:options:]
7   Release -1  6   00:14.494.395   UIKit   -[UIRuntimeConnection dealloc]
8   Release -1  5   00:14.494.414   UIKit   -[UIRuntimeConnection dealloc]
    Release (2) -2      00:14.494.435   UIKit   -[UINibDecoder finishDecoding]
10  Release -1  3   00:14.494.458   UIKit   -[UINibDecoder finishDecoding]
12  Retain  +1  3   00:14.496.105   Vit Calc    -[RBCViewController actionSheet:clickedButtonAtIndex:]
    Retain/Release (2)          00:14.496.275   UIKit   -[_UIFullscreenPresentationController _setPresentedViewController:]
14  Retain  +1  5   00:14.510.866   UIKit   -[UIViewController setChildModalViewController:]
15  Retain  +1  6   00:14.510.886   UIKit   -[UIApplication _addViewControllerForLockingStatusBarTintColor:]
    Retain/Release (2)          00:14.511.042   UIKit   -[UIPresentationController runTransitionForCurrentState]
17  Retain  +1  8   00:14.511.112   libsystem_sim_blocks.dylib  _Block_object_assign
18  Retain  +1  9   00:14.511.135   libsystem_sim_blocks.dylib  _Block_object_assign
19  Release -1  8   00:14.511.152   UIKit   -[UIActionSheet _indexTapped:]
20  Release -1  7   00:14.514.081   GraphicsServices    GSEventRunModal
21  Release -1  6   00:14.514.098   UIKit   -[UIStoryboardScene dealloc]
22  Retain  +1  7   00:14.556.304   UIKit   -[UIPeripheralHost(UIKitInternal) _beginPinningInputViewsOnBehalfOfResponder:]
23  Retain  +1  8   00:14.564.411   UIKit   -[UIViewController _setPresentedStatusBarViewController:]
24  Release -1  7   00:14.564.660   UIKit   __destroy_helper_block_1444
25  Release -1  6   00:14.564.715   UIKit   -[UIPeripheralHost(UIKitInternal) _stopPinningInputViewsOnBehalfOfResponder:]
26  Release -1  5   00:14.564.721   UIKit   __destroy_helper_block_382
    Retain/Release (2)          00:14.581.427   Foundation  +[NSConcreteNotification newTempNotificationWithName:object:userInfo:]
    Retain/Release (2)          00:14.595.199   Foundation  +[NSConcreteNotification newTempNotificationWithName:object:userInfo:]
    Retain/Release (4)          00:14.607.299   UIKit   -[UIResponder becomeFirstResponder]
34  Retain  +1  5   00:16.014.292   UIKit   -[UIViewController _dismissViewControllerWithAnimationController:interactionController:completion:]
    Retain/Release (2)          00:16.014.324   UIKit   -[UIPresentationController runTransitionForCurrentState]
36  Retain  +1  7   00:16.014.399   libsystem_sim_blocks.dylib  _Block_object_assign
37  Release -1  6   00:16.014.430   UIKit   -[UIViewController _dismissViewControllerWithAnimationController:interactionController:completion:]
38  Release -1  5   00:16.036.310   UIKit   -[UIViewController _setPresentedStatusBarViewController:]
39  Release -1  4   00:16.036.802   UIKit   __destroy_helper_block_382
42  Retain  +1  5   00:16.546.187   UIKit   -[UIViewController _didFinishDismissTransition]
43  Retain  +1  6   00:16.546.190   UIKit   -[UIApplication _removeViewControllerForLockingStatusBarTintColor:]
44  Release -1  5   00:16.546.190   UIKit   -[UIApplication _removeViewControllerForLockingStatusBarTintColor:]
45  Release -1  4   00:16.546.191   UIKit   -[UIApplication _removeViewControllerForLockingStatusBarTintColor:]
46  Release -1  3   00:16.546.192   UIKit   -[UIViewController setChildModalViewController:]
47  Release -1  2   00:16.546.195   UIKit   -[UIViewController _didFinishDismissTransition]
50  Zombie      -1  00:18.518.590   UIKit   -[UIPresentationController runTransitionForCurrentState]

50僵尸-100:18.518.590 UIKit -UIPresentationController runTransitionForCurrentState

短版本(过滤)

Event Type  ∆ RefCt RefCt   Timestamp   Responsible Library Responsible Caller
    Retain/Release (2)          00:14.496.275   UIKit   -[_UIFullscreenPresentationController _setPresentedViewController:]
1   Retain  +1  7   00:14.511.042   UIKit   -[UIPresentationController runTransitionForCurrentState]
2   Retain  +1  8   00:14.564.411   UIKit   -[UIViewController _setPresentedStatusBarViewController:]
3   Retain  +1  6   00:16.014.324   UIKit   -[UIPresentationController runTransitionForCurrentState]
4   Release -1  5   00:16.036.310   UIKit   -[UIViewController _setPresentedStatusBarViewController:]
6   Zombie      -1  00:18.518.590   UIKit   -[UIPresentationController runTransitionForCurrentState]

在短版本中，保留似乎实际上起到了相反的作用：

1   Retain  +1  7   00:14.511.042   UIKit   -[UIPresentationController runTransitionForCurrentState]
3   Retain  +1  6   00:16.014.324   UIKit   -[UIPresentationController runTransitionForCurrentState]

我试着在一个新的项目中复制这个，但做不到。

而且，似乎只有当我的UIActionSheet委托(设置为self)时才会发生。

在这一点上，我只想寄给苹果一份更简洁的bug报告，所以我只是想找出问题所在。

更新

可以繁殖。

当UIActionSheet在单独的方法中被初始化时，而不是在呈现它的方法中时，就会发生这种情况。和它的代表正在提交另一个ViewController。

对于exapmle：

@implementation RBCViewController
{
    UIActionSheet *actionSheet;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self createActionSheet];
}

- (void)createActionSheet
{
    actionSheet = [[UIActionSheet alloc]init];
}

- (IBAction)showActionSheet:(UIButton *)sender {

    // Add buttons, assign delegate here

    [actionSheet showInView:self.view];
}

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    // Present another ViewContoller here.
    // This will fail with 'Bad Access' on the second time
}

Answer 1

我也有过同样的问题。解决方案是在每次使用之后释放您的UIActionSheet，因为它将保存它用来显示自己的UIWindow (它有一个指向您提供的模式VC的unsafe_unretained指针)。

未来的读者:当心，当iOS8发布时，这可能不再是真的。