UIAlertView show crash - ios

Question

I make an UIAleartView show information when first init:
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#""
message:#"..."
delegate:self
cancelButtonTitle:#"..."
otherButtonTitles:#"...", nil];
alertView.tag = 1;
[alertView show];
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
switch (alertView.tag) {
case 1: {
[UICKeyChainStore setString:#"YES" forKey:kDebutFirstMsgShow];
if (buttonIndex == 0) {
NSNotificationCenter *noti = [NSNotificationCenter defaultCenter];
[noti postNotificationName:#"...." object:nil];
}
break;
}
default:
break;
}
}
And here is log:
2017-02-10 01:16:44.206 audition[1740:55532] *** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array'
*** First throw call stack:
(
0 CoreFoundation 0x000000010b09bd4b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x000000010aad421e objc_exception_throw + 48
2 CoreFoundation 0x000000010afcd2eb -[__NSArrayM objectAtIndex:] + 203
3 UIKit 0x0000000109854e8f __86-[_UIAlertControllerView _unlocalizedOrderedPresentableAlertActionViewRepresentations]_block_invoke + 68
4 CoreFoundation 0x000000010b02b0b2 __53-[__NSArrayM enumerateObjectsWithOptions:usingBlock:]_block_invoke + 114
5 CoreFoundation 0x000000010b02af42 -[__NSArrayM enumerateObjectsWithOptions:usingBlock:] + 194
6 UIKit 0x0000000109854dfc -[_UIAlertControllerView _unlocalizedOrderedPresentableAlertActionViewRepresentations] + 213
7 UIKit 0x00000001098543b5 -[_UIAlertControllerView _reloadInterfaceActionViewRepresentations] + 50
8 UIKit 0x0000000109855f6e -[_UIAlertControllerView _setVisualStyle:] + 380
9 UIKit 0x00000001090bab35 -[UIAlertController _updateProvidedStyleWithTraitCollection:] + 455
10 UIKit 0x00000001090bac0f -[UIAlertController _updateProvidedStyle] + 57
11 UIKit 0x00000001090bae7a -[UIAlertController traitCollectionDidChange:] + 236
12 UIKit 0x0000000108eedfac -[UIViewController _traitCollectionDidChange:] + 108
13 UIKit 0x0000000108eee0cf -[UIViewController _updateTraitsIfNecessary] + 269
14 UIKit 0x0000000108e12957 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 884
15 QuartzCore 0x000000010bb2abf8 -[CALayer layoutSublayers] + 146
16 QuartzCore 0x000000010bb1e440 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366
17 UIKit 0x0000000108e00928 -[UIView(Hierarchy) layoutBelowIfNeeded] + 1509
18 UIKit 0x0000000108df6e33 -[UIView(Geometry) setBounds:] + 2387
19 UIKit 0x0000000108df603d -[UIView(Geometry) _applyISEngineLayoutValuesToBoundsOnly:] + 608
20 UIKit 0x0000000108e0080e -[UIView(Hierarchy) layoutBelowIfNeeded] + 1227
21 UIKit 0x0000000108df315b -[UIView(Geometry) setFrame:] + 1297
22 UIKit 0x00000001090b9f26 -[UIAlertController loadView] + 201
23 UIKit 0x0000000108eef61c -[UIViewController loadViewIfRequired] + 201
24 UIKit 0x0000000108eefe70 -[UIViewController view] + 27
25 UIKit 0x0000000108f0a0a5 -[UIViewController _setPresentationController:] + 100
26 UIKit 0x0000000108f015f4 -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1355
27 UIKit 0x0000000108f0328e -[UIViewController _presentViewController:withAnimationController:completion:] + 4971
28 UIKit 0x0000000108f0626b -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 530
29 UIKit 0x0000000108f05d51 -[UIViewController presentViewController:animated:completion:] + 179
30 UIKit 0x00000001098413bf -[_UIAlertControllerShimPresenterWindow presentAlertController:animated:completionBlock:] + 642
31 UIKit 0x000000010983f6f6 -[_UIAlertControllerShimPresenter _presentAlertControllerAnimated:completion:] + 219
32 UIKit 0x00000001090d42e6 -[UIAlertView _showAnimated:] + 278
33 audition 0x00000001063f9840 -[DebutVC viewWillAppear:] + 448
34 UIKit 0x0000000108ef596f -[UIViewController _setViewAppearState:isAnimating:] + 692
35 UIKit 0x0000000108ef607f -[UIViewController __viewWillAppear:] + 147
36 UIKit 0x0000000108e0b59b __86+[UIView(Internal) _transitionFromView:toView:duration:options:animations:completion:]_block_invoke + 62
37 UIKit 0x0000000108e085c0 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:] + 581
38 UIKit 0x0000000108e087f2 +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:animations:start:completion:] + 145
39 UIKit 0x0000000108e0b4bf +[UIView(Internal) _transitionFromView:toView:duration:options:animations:completion:] + 603
40 UIKit 0x0000000108f1677a -[UIViewController(UIContainerViewControllerProtectedMethods) transitionFromViewController:toViewController:duration:options:animations:completion:] + 771
41 audition 0x000000010645c1b1 -[MHTabBarController setSelectedIndex:animated:] + 2849
42 audition 0x000000010645cca3 -[MHTabBarController tabButtonPressed:] + 99
43 UIKit 0x0000000108d4f8bc -[UIApplication sendAction:to:from:forEvent:] + 83
44 UIKit 0x0000000108ed5c38 -[UIControl sendAction:to:forEvent:] + 67
45 UIKit 0x0000000108ed5f51 -[UIControl _sendActionsForEvents:withEvent:] + 444
46 UIKit 0x0000000108ed4910 -[UIControl touchesBegan:withEvent:] + 304
47 UIKit 0x0000000108dbd285 -[UIWindow _sendTouchesForEvent:] + 2043
48 UIKit 0x0000000108dbec33 -[UIWindow sendEvent:] + 4011
49 UIKit 0x0000000108d6b9ab -[UIApplication sendEvent:] + 371
50 UIKit 0x000000010955872d __dispatchPreprocessedEventFromEventQueue + 3248
51 UIKit 0x0000000109551463 __handleEventQueue + 4879
52 CoreFoundation 0x000000010b040761 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
53 CoreFoundation 0x000000010b02598c __CFRunLoopDoSources0 + 556
54 CoreFoundation 0x000000010b024e76 __CFRunLoopRun + 918
55 CoreFoundation 0x000000010b024884 CFRunLoopRunSpecific + 420
56 GraphicsServices 0x000000010ca64a6f GSEventRunModal + 161
57 UIKit 0x0000000108d4dc68 UIApplicationMain + 159
58 audition 0x0000000106493c91 main + 241
59 libdyld.dylib 0x000000010d05868d start + 1
From the log file NSRangeException there is an array empty but i access to element 0 of it. But
Crash disappear when i comment [alertview show];
What is reason of this crash ?

Answer 1

The crash log shows that your code is happening here:
33 audition 0x00000001063f9840 -[DebutVC viewWillAppear:] + 448
You can't show an alert from viewWillAppear, because your view is not in the interface yet (it will appear, but it has not yet done so). Try moving your show code to viewDidAppear instead.