iPhone application crash on launch

Question

We are receiving a crash log from iTunes connect that is a little strange.

We were preivously having problems with our app taking to long to return from ApplicationDidFinishLaunching. This was caused by doing a too much work inside of applicationDidFinishLaunching and we exceeded the 20 second time out on slower devices.

To fix this we moved all of our setup code out of ApplicationDidFinishLaunching and moved it into a special secondaryLoadingController. On top of that we moved the setup code inside of that controller to a separate thread.

However, we are still seeing crash logs that say our app failed to launch in time even though the crash log shows a call to [UIApplication _reportAppLaunchFinished]. To me, this indicates that the app has finished launching and we should be free to take as long as we want to run our setup code. Below is the crash log.

Thanks for any help you can offer.

Incident Identifier: 429360D5-6B02-49BE-9A0F-164DC521BE36
Hardware Model:      iPod2,1
Process:         XYZ [357]
Path:            /var/mobile/Applications/D5038F26-CC5B-48E5-824E-090163B5C0C4/XYZ.app/XYZ
Identifier:      XYZ
Version:         ??? (???)
Code Type:       ARM (Native)
Parent Process:  launchd [1]



Date/Time:       2010-09-28 13:35:25.138 -0700
OS Version:      iPhone OS 4.0 (8A293)
Report Version:  104



Exception Type:  00000020
Exception Codes: 0x8badf00d
Highlighted Thread:  0



Application Specific Information:
com.xyz.xyz failed to launch in time
elapsed total CPU time (seconds): 20.180 (user 15.910, system 4.270), 100% CPU
elapsed application CPU time (seconds): 10.960, 54% CPU



Thread 0:
0   libobjc.A.dylib                   0x3523a50c objc_msgSend + 44
1   CoreFoundation                    0x363bf568 -[__NSArrayM addObject:]
2   XYZ                        0x0000a152 -[Database fetchDrinks:] + 290
3   XYZ                        0x0000677c -[Database getAllDrinks] + 136
4   XYZ                        0x0003a164 -[SecondaryLoadingViewController viewDidLoad] + 208
5   UIKit                             0x323e582c -[UIViewController view]
6   UIKit                             0x323f9628 -[UIViewController viewControllerForRotation]
7   UIKit                             0x323f9574 -[UIViewController _visibleView]
8   UIKit                             0x323f94fc -[UIViewController rotatingContentViewForWindow:]
9   UIKit                             0x3249a514 -[UIClientRotationContext initWithClient:toOrientation:duration:andWindow:]
10  UIKit                             0x32499314 -[UIWindow _setRotatableClient:toOrientation:duration:force:]
11  UIKit                             0x32497d78 -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:]
12  UIKit                             0x32497534 -[UIViewController presentModalViewController:withTransition:]
13  UIKit                             0x324977fc -[UIViewController _tryRecursivelyPresentModalViewController:withTransition:]
14  UIKit                             0x324977c0 -[UIViewController _tryRecursivelyPresentModalViewController:withTransition:]
15  UIKit                             0x32496e00 -[UIViewController presentModalViewController:withTransition:]
16  UIKit                             0x3249699c -[UIViewController presentModalViewController:animated:]
17  XYZ                        0x000044a2 -[HomeViewController viewDidLoad] + 82
18  UIKit                             0x323e582c -[UIViewController view]
19  UIKit                             0x323fd68c -[UIViewController contentScrollView]
20  UIKit                             0x323fd4ac -[UINavigationController _computeAndApplyScrollContentInsetDeltaForViewController:]
21  UIKit                             0x323fd358 -[UINavigationController _layoutViewController:]
22  UIKit                             0x323fccb8 -[UINavigationController _startTransition:fromViewController:toViewController:]
23  UIKit                             0x323fca1c -[UINavigationController _startDeferredTransitionIfNeeded]
24  UIKit                             0x323fc90c -[UINavigationController viewWillLayoutSubviews]
25  UIKit                             0x323fc43c -[UILayoutContainerView layoutSubviews]
26  UIKit                             0x32370ab0 -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
27  CoreFoundation                    0x363c85ba -[NSObject(NSObject) performSelector:withObject:]
28  QuartzCore                        0x30c8c61c 0x30c82000 + 42524
29  QuartzCore                        0x30c8c2a4 0x30c82000 + 41636
30  QuartzCore                        0x30c8bbb0 0x30c82000 + 39856
31  QuartzCore                        0x30c8b7d8 0x30c82000 + 38872
32  QuartzCore                        0x30c8b684 0x30c82000 + 38532
33  UIKit                             0x323d99d4 -[UIApplication _reportAppLaunchFinished]
34  UIKit                             0x3251d77c -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:]
35  UIKit                             0x323d87b8 -[UIApplication handleEvent:withNewEvent:]
36  UIKit                             0x323d7eb4 -[UIApplication sendEvent:]
37  UIKit                             0x323d77e8 _UIApplicationHandleEvent
38  GraphicsServices                  0x33c4dedc PurpleEventCallback
39  CoreFoundation                    0x364142ac __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__
40  CoreFoundation                    0x364161d6 __CFRunLoopDoSource1
41  CoreFoundation                    0x3641718e __CFRunLoopRun
42  CoreFoundation                    0x363be0bc CFRunLoopRunSpecific
43  CoreFoundation                    0x363bdfca CFRunLoopRunInMode
44  UIKit                             0x32363b18 -[UIApplication _run]
45  UIKit                             0x32361fb8 UIApplicationMain
46  XYZ                        0x00002b20 main + 36
47  XYZ                        0x00002af0 start + 32

UPDATE I am attempting to run the time consuming import code (only happens on an application update) on a separate thread. I am even updating the GUI using an AlertView with an embedded progress bar so the user knows something is still happening. During our testing process this works fine. Below is the thread code that seems to not be working. The crash log seems to indicate that all work is being done on the main thread.

    if ([database appDidUpdate] == YES) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    dbImportThread = [[NSThread alloc] initWithTarget:self selector:@selector(import) object:nil];
    [dbImportThread start];
    [pool release]; 

- (void)import {
 //do importing work and update the gui with the progress
}

Answer 1

You are still blocking the main thread too long - be it during launch or later. Only do lightweight GUI work on the main thread. The main thread is also blocked if you perform work on a second thread but wait in your main thread for the results.

Instruments is your friend here.