尝试使用Xamarin Studio中的自动升级工具启动我升级到统一API的应用时出现异常。我可以在iPhone模拟器中看到启动画面显示大约一秒钟，然后在Main方法中抛出以下异常。
Objective-C exception thrown. Name: NSInvalidArgumentException Reason: *** -[__NSArrayM insertObject:atIndex:]: object cannot be nil
Native stack trace:
0 CoreFoundation 0x00940a94 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x087ffe02 objc_exception_throw + 50
2 CoreFoundation 0x007ee3a1 -[__NSArrayM insertObject:atIndex:] + 881
3 CoreFoundation 0x007ee001 -[__NSArrayM addObject:] + 65
4 UIKit 0x0342e9b6 -[UINavigationController _navigationItems] + 341
5 UIKit 0x0342c3ac -[UINavigationController initWithCoder:] + 1009
6 UIKit 0x0364c834 -[UIClassSwapper initWithCoder:] + 279
7 UIKit 0x03846e99 UINibDecoderDecodeObjectForValue + 739
8 UIKit 0x03846bae -[UINibDecoder decodeObjectForKey:] + 320
9 UIKit 0x0333a812 -[UINavigationBar initWithCoder:] + 472
10 UIKit 0x03846e99 UINibDecoderDecodeObjectForValue + 739
11 UIKit 0x03846bae -[UINibDecoder decodeObjectForKey:] + 320
12 UIKit 0x0332f9a9 -[UINavigationItem initWithCoder:] + 899
13 UIKit 0x03846e99 UINibDecoderDecodeObjectForValue + 739
14 UIKit 0x03846bae -[UINibDecoder decodeObjectForKey:] + 320
15 UIKit 0x033f217e -[UIViewController initWithCoder:] + 528
16 UIKit 0x03455f5e -[UITabBarController initWithCoder:] + 68
17 UIKit 0x0364c834 -[UIClassSwapper initWithCoder:] + 279
18 UIKit 0x03846e99 UINibDecoderDecodeObjectForValue + 739
19 UIKit 0x03846bae -[UINibDecoder decodeObjectForKey:] + 320
20 UIKit 0x0364c403 -[UIRuntimeConnection initWithCoder:] + 148
21 UIKit 0x03846e99 UINibDecoderDecodeObjectForValue + 739
22 UIKit 0x038470aa UINibDecoderDecodeObjectForValue + 1268
23 UIKit 0x03846bae -[UINibDecoder decodeObjectForKey:] + 320
24 UIKit 0x0364b43d -[UINib instantiateWithOwner:options:] + 1411
25 UIKit 0x039f4ace -[UIStoryboard instantiateViewControllerWithIdentifier:] + 220
26 UIKit 0x039f4c5b -[UIStoryboard instantiateInitialViewController] + 78
27 UIKit 0x032355e7 -[UIApplication _loadMainStoryboardFileNamed:bundle:] + 99
28 UIKit 0x03235964 -[UIApplication _loadMainInterfaceFile] + 292
29 UIKit 0x03233d35 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1575
30 UIKit 0x03257905 __84-[UIApplication _handleApplicationActivationWithScene:transitionContext:completion:]_block_invoke3171 + 68
31 UIKit 0x03230bae -[UIApplication workspaceDidEndTransaction:] + 163
32 FrontBoardServices 0x0b013ccc __37-[FBSWorkspace clientEndTransaction:]_block_invoke_2 + 71
33 FrontBoardServices 0x0b0137a3 __40-[FBSWorkspace _performDelegateCallOut:]_block_invoke + 54
34 FrontBoardServices 0x0b0311cb -[FBSSerialQueue _performNext] + 184
35 FrontBoardServices 0x0b031602 -[FBSSerialQueue _performNextFromRunLoopSource] + 52
36 FrontBoardServices 0x0b0308fe FBSSerialQueueRunLoopSourceHandler + 33
37 CoreFoundation 0x0085ae7f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
38 CoreFoundation 0x00850b0b __CFRunLoopDoSources0 + 523
39 CoreFoundation 0x0084ff28 __CFRunLoopRun + 1032
40 CoreFoundation 0x0084f866 CFRunLoopRunSpecific + 470
41 CoreFoundation 0x0084f67b CFRunLoopRunInMode + 123
42 UIKit 0x03230497 -[UIApplication _run] + 540
43 UIKit 0x03235cc1 UIApplicationMain + 160
44 ??? 0x17eb7288 0x0 + 401306248
45 ??? 0x17eb7080 0x0 + 401305728
46 ??? 0x17eb5210 0x0 + 401297936
47 ??? 0x17eb4f48 0x0 + 401297224
48 ??? 0x17eb50d8 0x0 + 401297624
49 myAppiOS 0x00207d9b mono_jit_runtime_invoke + 715
50 myAppiOS 0x002a66ef mono_runtime_invoke + 127
51 myAppiOS 0x002ab8e1 mono_runtime_exec_main + 401
52 myAppiOS 0x002ab697 mono_runtime_run_main + 711
53 myAppiOS 0x00167fad mono_jit_exec + 93
54 myAppiOS 0x00384bd1 xamarin_main + 2497
55 myAppiOS 0x00385562 main + 114
56 libdyld.dylib 0x08cd9a21 start + 1
57 ??? 0x00000003 0x0 + 3
这是默认的Main方法：
using System.Collections.Generic;
using System.Linq;
using Foundation;
using UIKit;
namespace myAppiOS
{
public class Application
{
// This is the main entry point of the application.
static void Main (string[] args)
{
// if you want to use a different Application Delegate class from "AppDelegate"
// you can specify it here.
UIApplication.Main (args, null, "AppDelegate");
}
}
}
有什么想法吗？
答案 0 :(得分：1)
我只有分享的疑难解答提示。
问题出在StackTrace的第3行：
2 CoreFoundation 0x007ee3a1 - [__ NSArrayM insertObject：atIndex ：] + 881
很明显，你正在添加一个项目， libobjc.A.dylib 这个东西正在陷入困境：
1 libobjc.A.dylib 0x087ffe02 objc_exception_throw + 50 2
为了诊断根本原因，需要经典的ASP故障排除方法。 Debug.Print语句无处不在！
您必须在代码中搜索要将项目添加到集合的位置。那个地方可能会在instantiateViewControllerWithIdentifier电话中。
因为在您可以单步执行代码之前抛出异常，唯一的其他选项（除了内存转储调试）是注释掉或Debug.Print所有调用以缩小问题范围！一个接一个:(
这是一个PITA和I do empathize with you。我认为它是由于根据错误消息添加了一个空对象对象不能为零
它可能是任何东西，并且添加null可能是另一个问题的症状。 也许您添加的项目太大，可能超出了数组的范围，也许您只需要清理解决方案并重新部署。
如果您可以超越UIApplication.Main (args, null, "AppDelegate");，也许尝试启用异常可能会有所帮助，例如：https://stackoverflow.com/a/32754919/495455