UIViewController初始化没有 init 导致的 B
2019-11-06 本文已影响0人
韦弦Zhy
今天的这个bug，真的出现在我的项目里面了。。。知道原因时差点破腹自尽
我自闭了
事情是这样的，原本有个控制器是用Nav push 来显示的，现在需要改成用modal present 来显示。。还有比这个更容易的需求吗？？？？
但是bug出现了。。。
写个简易代码演示下：
// 控制器B的viewDidLoad()
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
UIView *view = [[UIView alloc] init];
view.backgroundColor = [UIColor redColor];
view.frame = CGRectMake(0, 0, 100, 100);
view.center = self.view.center;
[self.view addSubview:view];
}
这代码够简单吧，加了全局断点，然后如下：
全局断点
话说
*** Assertion failure in UITraitCollection * _Nonnull _UIGetCurrentFallbackTraitCollection(void)(), /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKitCore_Sim/UIKit-3899.13.13/_UIFallbackEnvironment.m:91这个错误我是左查右查都不知道为啥，为啥直接就停在这了。。。
好吧，我去掉断点
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '<NewViewController: 0x7fa6d6f0ace0> returned nil from -traitCollection, which is not allowed.'
*** First throw call stack:
(
0 CoreFoundation 0x00007fff23b98bde __exceptionPreprocess + 350
1 libobjc.A.dylib 0x00007fff503b5b20 objc_exception_throw + 48
2 CoreFoundation 0x00007fff23b98958 +[NSException raise:format:arguments:] + 88
3 Foundation 0x00007fff255eb7be -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 166
4 UIKitCore 0x00007fff46dd08bd _UIGetCurrentFallbackTraitCollection + 962
5 UIKitCore 0x00007fff476029fa UIViewCommonInitWithFrame + 617
6 UIKitCore 0x00007fff47602753 -[UIView initWithFrame:] + 98
7 UIKitCore 0x00007fff47601fa3 -[UIView init] + 44
8 PresentDemo 0x000000010ab18f05 -[NewViewController viewDidLoad] + 85
9 UIKitCore 0x00007fff46af87c2 -[UIViewController _sendViewDidLoadWithAppearanceProxyObjectTaggingEnabled] + 83
10 UIKitCore 0x00007fff46afd6d3 -[UIViewController loadViewIfRequired] + 1084
11 UIKitCore 0x00007fff46afdaf0 -[UIViewController view] + 27
12 UIKitCore 0x00007fff46a1776d -[_UIFullscreenPresentationController _setPresentedViewController:] + 84
13 UIKitCore 0x00007fff46a0b105 -[UIPresentationController initWithPresentedViewController:presentingViewController:] + 184
14 UIKitCore 0x00007fff46b0ec8e -[UIViewController _presentViewController:withAnimationController:completion:] + 3553
15 UIKitCore 0x00007fff46b1180b __63-[UIViewController _presentViewController:animated:completion:]_block_invoke + 98
16 UIKitCore 0x00007fff46b11d23 -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 511
17 UIKitCore 0x00007fff46b11769 -[UIViewController _presentViewController:animated:completion:] + 187
18 UIKitCore 0x00007fff46b119d0 -[UIViewController presentViewController:animated:completion:] + 150
19 PresentDemo 0x000000010ab18c82 -[ViewController viewDidAppear:] + 146
20 UIKitCore 0x00007fff46b036a2 -[UIViewController _setViewAppearState:isAnimating:] + 934
21 UIKitCore 0x00007fff46a57e2d -[UINavigationController viewDidAppear:] + 173
22 UIKitCore 0x00007fff46b036a2 -[UIViewController _setViewAppearState:isAnimating:] + 934
23 UIKitCore 0x00007fff46b040a6 -[UIViewController _endAppearanceTransition:] + 196
24 UIKitCore 0x00007fff46a0bf2b __48-[UIPresentationController transitionDidFinish:]_block_invoke + 138
25 UIKitCore 0x00007fff4716b85a _runAfterCACommitDeferredBlocks + 352
26 UIKitCore 0x00007fff4715c63c _cleanUpAfterCAFlushAndRunDeferredBlocks + 248
27 UIKitCore 0x00007fff4718bc6e _afterCACommitHandler + 85
28 CoreFoundation 0x00007fff23afaeb7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
29 CoreFoundation 0x00007fff23af594e __CFRunLoopDoObservers + 430
30 CoreFoundation 0x00007fff23af5fca __CFRunLoopRun + 1514
31 CoreFoundation 0x00007fff23af56b6 CFRunLoopRunSpecific + 438
32 GraphicsServices 0x00007fff3815cbb0 GSEventRunModal + 65
33 UIKitCore 0x00007fff47162a67 UIApplicationMain + 1621
34 PresentDemo 0x000000010ab191a4 main + 116
35 libdyld.dylib 0x00007fff5123bcf5 start + 1
36 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '<NewViewController: 0x7fa6d6f0ace0> returned nil from -traitCollection, which is not allowed.'
然后自闭了。。。。
直接push代码如下：
[self.navigationController pushViewController:[NewViewController alloc] animated:YES];
一点毛病没有，啥都正常。。。
所以我改的modal代码：
[self presentViewController:[NewViewController alloc] animated:YES completion:nil];
真的是疯了，主要是注意力全在 NewViewController 中。。。最后才看到，没有 init
[self presentViewController:[[NewViewController alloc] init] animated:YES completion:nil];
。。。。。。。。。。
心中一千匹草泥马奔过。。。。
所以大家要细心啊。。。
