Simulator上的Xcode应用程序可以在真实设备崩溃时正常工作

Question

I have a strange problem, whenever i run my app on the iPad simulator it works perfectly but if i try on a real device (iPad air iOS 7.0.4) it crashes while attempting this piece of code.

I have :

Nav controller embedded in a master detail split view controller (will call A) -> replace segue ->

uitableViewController -> replace segue ->

someViewController (will call B)

and now.. replace segue back to the Nav Controller (all are master detail) and here it crashed on the real device giving only: (lldb)

now this is B implementation

- (IBAction)backToTable:(id)sender
{
    id detail = self.splitViewController.viewControllers[1];
    if(detail) { // iPad
        [self performSegueWithIdentifier:@"backToTable" sender:self];
    }
    else       // iPhone
        [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"backToTable"]){
        ViewControllerA *destViewController = [[[segue destinationViewController] viewControllers] objectAtIndex:0];
        destViewController.boolForSegue = @"true";
    }
}

and this is A

.h
@property (strong) NSString *boolForSegue;

.m

-(void)viewWillAppear:(BOOL)animated
{
    if ([_boolForSegue isEqualToString:@"true"]){
        [self unlockView];
    }
}

- (void)unlockView
{
    [self performSegueWithIdentifier:@"mySegue" sender:self];
}

I repeat that on simulator works perfectly no issue at all. What could be the problem??

EDIT:

crash log
Date/Time:           2014-02-06 23:00:34.420 +0100
OS Version:          iOS 7.0.4 (11B554a)
Report Version:      104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000153edbeb8
Triggered by Thread:  0

Thread 0 Crashed:
0   libobjc.A.dylib                 0x00000001908879d0 objc_msgSend + 16
1   UIKit                           0x00000001873fb09c -[UISearchBar willMoveToSuperview:] + 64
2   UIKit                           0x00000001875d4ea0 __UIViewWillBeRemovedFromSuperview + 188
3   UIKit                           0x00000001873043f0 -[UIView(Hierarchy) removeFromSuperview] + 68
4   UIKit                           0x00000001873074f8 -[UIView dealloc] + 420
5   UIKit                           0x00000001873eb350 -[UIScrollView dealloc] + 968
6   UIKit                           0x00000001874abc3c -[UITableView dealloc] + 1300
7   UIKit                           0x000000018749c108 -[UIViewController dealloc] + 460
8   UIKit                           0x00000001875205f8 -[UITableViewController dealloc] + 288
9   UIKit                           0x000000018782cdc4 -[UIStoryboardSegue dealloc] + 68
10  libobjc.A.dylib                 0x00000001908893d0 (anonymous namespace)::AutoreleasePoolPage::pop(void*) + 520
11  CoreFoundation                  0x000000018433589c _CFAutoreleasePoolPop + 24
12  UIKit                           0x00000001872fde34 _wrapRunLoopWithAutoreleasePoolHandler + 72
13  CoreFoundation                  0x00000001843f77dc __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 28
14  CoreFoundation                  0x00000001843f4a64 __CFRunLoopDoObservers + 368
15  CoreFoundation                  0x00000001843f4df0 __CFRunLoopRun + 760
16  CoreFoundation                  0x0000000184335b34 CFRunLoopRunSpecific + 448
17  GraphicsServices                0x0000000189d1782c GSEventRunModal + 164
18  UIKit                           0x00000001873740e4 UIApplicationMain + 1152
19  MasterSecurity                  0x000000010006f688 main (main.m:16)
20  libdyld.dylib                   0x0000000190e77a9c start + 0

Thread 1:
0   libsystem_kernel.dylib          0x0000000190f59ac8 kevent64 + 8
1   libdispatch.dylib               0x0000000190e5dd74 _dispatch_mgr_thread + 48

Thread 2:
0   libsystem_kernel.dylib          0x0000000190f72e74 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x0000000190ff17a4 start_wqthread + 0

Thread 3:
0   libsystem_kernel.dylib          0x0000000190f72e74 __workq_kernreturn + 8
1   libsystem_pthread.dylib         0x0000000190ff17a4 start_wqthread + 0

Thread 0 crashed with ARM Thread State (64-bit):
    x0: 0x00000001701669c0   x1: 0x000000018798d5a1   x2: 0x0000000000000000   x3: 0x0000000000000000
    x4: 0x0000000000000000   x5: 0x0000000000000000   x6: 0x0000000000000000   x7: 0x0000000000000000
    x8: 0x0000000191a40750   x9: 0x0000000153edbea8  x10: 0x000011d61ce68cd1  x11: 0x000000050000000f
   x12: 0x00000001703e35e0  x13: 0xbaddd0ad53edbead  x14: 0x000000000000004c  x15: 0x0000000170036440
   x16: 0x00000001908879c0  x17: 0x00000001908a1b6c  x18: 0x0000000000000000  x19: 0x000000012450fdc0
   x20: 0x0000000124846a00  x21: 0x0000000191a7f000  x22: 0x0000000124846a00  x23: 0x0000000191a83000
   x24: 0x000000000000001e  x25: 0x000000018798df25  x26: 0x0000000124513b40  x27: 0x0000000000000001
   x28: 0x0000000191ac3550  fp: 0x000000016fda21c0   lr: 0x00000001873fb1d0
    sp: 0x000000016fda21a0   pc: 0x00000001908879d0 cpsr: 0x20000000

Answer 1

In your A implementation, in viewWillAppear: (before the view controller has finished appearing) you're calling a method that calls performSegueWithIdentifier: , which will try to display another view controller. You have to wait until the first segue has finished first. So if you move that call to viewDidAppear: instead, it will fix your problem.

Remember, don't try to display a view controller while another one is still in the process of being displayed.