iOS Zombie - 无法弄清楚为什么对象被释放

Question

我正在尝试调试一些有exc_bad_access崩溃的代码。看来我有一个僵尸，但我无法弄清楚为什么对象被解除分配。这是一个针对iOS构建的Unity3D项目。有问题的代码是.mm文件，所以ObjectiveC ++。

因此，仪器显示正在解除分配的功能，但我并不真正了解正在发生的事情。 Responsible Caller是一个名为LoadVideo的函数，它包含在一个'extern“C”中。代码如下：

extern "C"
{
void LoadVideo()
{
    // get the current UIViewController
    UIViewController *viewController = UnityGetGLViewController();
    // create the videLoader object
    VideoLoaderUIObject * vidLoader = [VideoLoaderUIObject new];

    // start up our loading screen
    gSavingVideoAlert = [[CustomIOS7AlertView alloc] init];

    UIView* uiViewLoading = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 125)];

    UILabel* loadingLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 300, 40)];

    loadingLabel.numberOfLines = 2;
    [loadingLabel setText:@"Loading videos\nPlease Wait..."];
    [loadingLabel setTextAlignment:NSTextAlignmentCenter];
    [loadingLabel setTextColor:[UIColor blackColor]];
    [loadingLabel setBackgroundColor:[UIColor clearColor]];
    [loadingLabel setFont:[UIFont fontWithName: @"Trebuchet MS" size: 14.0f]];
    [uiViewLoading addSubview:loadingLabel];

    UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

    // Adjust the indicator so it is up a few pixels from the bottom of the alert
    indicator.center = CGPointMake(uiViewLoading.bounds.size.width / 2, uiViewLoading.bounds.size.height - 50);
    [indicator startAnimating];

    [uiViewLoading addSubview:indicator];
    [gSavingVideoAlert setContainerView:uiViewLoading];

    [gSavingVideoAlert show];

    // open the media gallery
    [vidLoader startMediaBrowserFromViewController: viewController usingDelegate: vidLoader];

#ifdef DEBUG_LOGS
    NSLog(@"video path %@", [vidLoader VideoPath]);
#endif

}
}

问题似乎出现在这一行：

[vidLoader startMediaBrowserFromViewController: viewController usingDelegate: vidLoader];

vidLoader对象来自VideoLoaderUIObject类，定义为：

@interface VideoLoaderUIObject : UIImagePickerController <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
{
    @private
    bool mIsUsingCam;
    NSMutableArray* mAssets;
    NSMutableArray *mVidIPod;
    NSMutableArray *mVidItems;
    std::vector<UIInterfaceOrientation> mVidOrientations;

    MyCustomViewController* mScrollViewController;
}

Instruments的输出如下：

什么阻止了vidLoader对象被保留？