应用程序崩溃在iOS 8中工作的iOS 8中

Question

如果我将带有动画的视图设置为YES，则应用程序崩溃，下面是堆栈跟踪。如果我在没有动画的情况下推动它正常工作。

-[NewsFeedDetailView viewWillAppear:]
Nov 26 17:58:48  <Error>: -[NSNull length]: unrecognized selector sent to instance 0x307c1400
Nov 26 17:58:48  <Warning>: Stack Trace:: (
        0   CoreFoundation                      0x225f8d7f <redacted> + 150
        1   libobjc.A.dylib                     0x2fe57c77 objc_exception_throw + 38
        2   CoreFoundation                      0x225fe22d <redacted> + 0
        3   CoreFoundation                      0x225fc109 <redacted> + 712
        4   CoreFoundation                      0x2252d938 _CF_forwarding_prep_0 + 24
        5   UIKit                               0x25aa7a9b <redacted> + 38
        6   UIKit                               0x25b16d5b <redacted> + 66
        7   UIKit                               0x25b16d11 <redacted> + 84
        8   UIKit                               0x25b16c99 <redacted> + 400
        9   QuartzCore                          0x254f4681 <redacted> + 228
        10  QuartzCore                          0x254de0c1 <redacted> + 2068
        11  QuartzCore                          0x255bfb4d <redacted> + 52
        12  QuartzCore                          0x254dd8a5 <redacted> + 88
        13  QuartzCore                          0x254dd555 <redacted> + 1156
        14  QuartzCore                          0x254c1b1d <redacted> + 200
        15  QuartzCore                          0x254c17e1 <redacted> + 24
        16  QuartzCore                          0x254c11c7 <redacted> + 222
        17  QuartzCore                          0x254c0fd1 <redacted> + 324
        18  UIKit                               0x25a9c5f9 <redacted> + 1384
        19  CoreFoundation                      0x225bf5e7 <redacted> + 14
        20  CoreFoundation                      0x225be9fb <redacted> + 222
        21  CoreFoundation                      0x225bd079 <redacted> + 768
        22  CoreFoundation                      0x2250a981 CFRunLoopRunSpecific + 476
        23  CoreFoundation                      0x2250a793 CFRunLoopRunInMode + 106
        24  GraphicsServices                    0x298e3051 GSEventRunModal + 136
        25  UIKit                               0x25afc981 UIApplicationMain + 1440
        26  W I T Party                         0x0014b1fd main + 220
        27  libdyld.dylib                       0x303f3aaf <redacted> + 2
    )

请帮我解决这个问题

这是我的观点WillAppear。我只是打电话给超级。

-(void)viewWillAppear:(BOOL)animated {
    NSLog(@"%s",__func__);

    [super viewWillAppear:NO];
}