我在Monotouch iOS 6中使用MFMailComposeViewController时出现了一个奇怪的错误，但它在iOS 5.1中运行良好：
*** Assertion failure in NSDictionary *_UIRecordArgumentOfInvocationAtIndex(NSInvocation *, NSUInteger, BOOL)(), /SourceCache/UIKit/UIKit-2372/UIAppearance.m:1118
以下是代码：
MFMailComposeViewController _mail;
public void SendFeedbackMail (string email_subject, string email_message_body, string[] email_recipients)
{
if (MFMailComposeViewController.CanSendMail) {
_mail = new MFMailComposeViewController ();
_mail.SetSubject (email_subject);
_mail.SetToRecipients (email_recipients);
_mail.SetMessageBody (email_message_body + "\n", false);
_mail.Finished += HandleMailFinished;
root_controller.PresentViewController(_mail, true, null);
} else {
//handle not being able to send mail
UIAlertView alert = new UIAlertView ("Mail Alert", "Error: Check your eMail configuration", null, "OK", null);
alert.Show ();
}
}
模拟器上的原生堆栈跟踪：
Native stacktrace:
0 MyAppProject 0x0007ba5c mono_handle_native_sigsegv + 284
1 MyAppProject 0x00004a62 mono_sigsegv_signal_handler + 178
2 libsystem_c.dylib 0x93ad486b _sigtramp + 43
3 ??? 0xffffffff 0x0 + 4294967295
4 MyAppProject 0x0014e8be mono_runtime_invoke + 126
5 MyAppProject 0x001ec80f monotouch_exception_handler + 63
6 CoreFoundation 0x020e0318 __handleUncaughtException + 728
7 libobjc.A.dylib 0x0228d0b9 _ZL15_objc_terminatev + 86
8 libstdc++.6.dylib 0x0289e652 _ZSt9terminatev + 21
9 libobjc.A.dylib 0x0228d039 _destroyAltHandlerList + 0
10 libdispatch.dylib 0x0299d027 _dispatch_client_callout + 33
11 libdispatch.dylib 0x0298cd5f _dispatch_barrier_sync_f_invoke + 58
12 libdispatch.dylib 0x0298caa3 dispatch_barrier_sync_f + 108
13 libdispatch.dylib 0x0298ce5e dispatch_sync + 45
14 UIKit 0x00f7ffad __76-[_UIRemoteViewControllerConnectionRequest _connectToViewControllerOperator]_block_invoke_0 + 105
15 UIKit 0x00f8be46 __block_global_0 + 54
16 libdispatch.dylib 0x0299d014 _dispatch_client_callout + 14
17 libdispatch.dylib 0x0298f09f dispatch_once_f + 57
18 libdispatch.dylib 0x0298f061 dispatch_once + 31
19 UIKit 0x00f8be0a __73-[_UIViewServiceSessionEndpoint connectToDeputyOfType:connectionHandler:]_block_invoke_0 + 105
20 UIKit 0x00f8c002 __73-[_UIViewServiceSessionEndpoint connectToDeputyOfType:connectionHandler:]_block_invoke_040 + 25
21 UIKit 0x00fe94e9 __block_global_0 + 32
22 libdispatch.dylib 0x0298b53f _dispatch_call_block_and_release + 15
23 libdispatch.dylib 0x0299d014 _dispatch_client_callout + 14
24 libdispatch.dylib 0x0298d418 _dispatch_queue_drain + 239
25 libdispatch.dylib 0x0298d2a6 _dispatch_queue_invoke + 59
26 libdispatch.dylib 0x0298e280 _dispatch_root_queue_drain + 231
27 libdispatch.dylib 0x0298e450 _dispatch_worker_thread2 + 39
28 libsystem_c.dylib 0x93aeae12 _pthread_wqthread + 441
29 libsystem_c.dylib 0x93ad2cca start_wqthread + 30
同样在模拟器上，应用程序会挂起一段时间，然后在调试器上抛出异常并崩溃：
Mono.Debugger.Soft.VMDisconnectedException: Exception of type 'Mono.Debugger.Soft.VMDisconnectedException' was thrown. at Mono.Debugger.Soft.Connection.SendReceive (CommandSet command_set, Int32 command, Mono.Debugger.Soft.PacketWriter packet) [0x00117] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/Connection.cs:1420
at Mono.Debugger.Soft.Connection.Type_GetCustomAttributes (Int64 id, Int64 attr_type_id, Boolean inherit) [0x00000] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/Connection.cs:1986
at Mono.Debugger.Soft.TypeMirror.GetCAttrs (Mono.Debugger.Soft.TypeMirror type, Boolean inherit) [0x0003d] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/TypeMirror.cs:679
at Mono.Debugger.Soft.TypeMirror.GetCustomAttributes (Boolean inherit) [0x00000] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/TypeMirror.cs:664
at Mono.Debugging.Soft.SoftDebuggerAdaptor.OnGetTypeDisplayData (Mono.Debugging.Evaluation.EvaluationContext gctx, System.Object type) [0x0001e] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/addins/MonoDevelop.Debugger.Soft/Mono.Debugging.Soft/SoftDebuggerAdaptor.cs:1066
Application Terminated
Mono.Debugger.Soft.VMDisconnectedException: Exception of type 'Mono.Debugger.Soft.VMDisconnectedException' was thrown.
at Mono.Debugger.Soft.Connection.SendReceive (CommandSet command_set, Int32 command, Mono.Debugger.Soft.PacketWriter packet) [0x0013f] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/Connection.cs:1425
at Mono.Debugger.Soft.Connection.Type_GetMethodsByNameFlags (Int64 id, System.String name, Int32 flags, Boolean ignoreCase) [0x00016] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/Connection.cs:2002
at Mono.Debugger.Soft.TypeMirror.GetMethodsByNameFlags (System.String name, BindingFlags flags, Boolean ignoreCase) [0x0001c] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/contrib/Mono.Debugger.Soft/Mono.Debugger.Soft/TypeMirror.cs:691
at Mono.Debugging.Soft.SoftDebuggerAdaptor.OverloadResolve (Mono.Debugging.Soft.SoftEvaluationContext ctx, System.String methodName, Mono.Debugger.Soft.TypeMirror type, Mono.Debugger.Soft.TypeMirror[] argtypes, Boolean allowInstance, Boolean allowStatic, Boolean throwIfNotFound) [0x00073] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/addins/MonoDevelop.Debugger.Soft/Mono.Debugging.Soft/SoftDebuggerAdaptor.cs:1231
at Mono.Debugging.Soft.SoftDebuggerAdaptor.CallToString (Mono.Debugging.Evaluation.EvaluationContext ctx, System.Object obj) [0x00107] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/addins/MonoDevelop.Debugger.Soft/Mono.Debugging.Soft/SoftDebuggerAdaptor.cs:91
at Mono.Debugging.Evaluation.ObjectValueAdaptor.TargetObjectToObject (Mono.Debugging.Evaluation.EvaluationContext ctx, System.Object obj) [0x00349] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/ObjectValueAdaptor.cs:980
at Mono.Debugging.Soft.SoftDebuggerAdaptor.TargetObjectToObject (Mono.Debugging.Evaluation.EvaluationContext gctx, System.Object obj) [0x001a5] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/addins/MonoDevelop.Debugger.Soft/Mono.Debugging.Soft/SoftDebuggerAdaptor.cs:1400
at Mono.Debugging.Evaluation.ExpressionEvaluator.TargetObjectToExpression (Mono.Debugging.Evaluation.EvaluationContext ctx, System.Object obj) [0x00000] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/ExpressionEvaluator.cs:83
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValueImpl (Mono.Debugging.Evaluation.EvaluationContext ctx, IObjectValueSource source, ObjectPath path, System.Object obj, ObjectValueFlags flags) [0x000f5] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/ObjectValueAdaptor.cs:385
at Mono.Debugging.Evaluation.ObjectValueAdaptor.CreateObjectValue (Mono.Debugging.Evaluation.EvaluationContext ctx, IObjectValueSource source, ObjectPath path, System.Object obj, ObjectValueFlags flags) [0x00000] in /Users/builder/data/lanes/monodevelop-lion-monodevelop-3.0.4-branch/ea010826/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/ObjectValueAdaptor.cs:93
设备上的原生堆栈跟踪：
0 MyAppProject 0x01b39e85 mono_handle_native_sigsegv + 244
1 MyAppProject 0x01afe3cf mono_sigsegv_signal_handler + 130
2 libsystem_c.dylib 0x3aaa8e93 _sigtramp + 42
3 MyAppProject 0x01b92a9d mono_domain_get + 20
4 MyAppProject 0x01b5d53b mono_runtime_invoke + 90
5 MyAppProject 0x01bbd8c0 monotouch_exception_handler + 72
6 CoreFoundation 0x36cee57f <redacted> + 614
7 libobjc.A.dylib 0x34ffea65 <redacted> + 128
8 libc++abi.dylib 0x33e4807b <redacted> + 78
9 libc++abi.dylib 0x33e48114 <redacted> + 19
10 libc++abi.dylib 0x33e49513 __cxa_throw + 122
11 libobjc.A.dylib 0x34ffe9bf objc_exception_throw + 94
12 CoreFoundation 0x36cee15d <redacted> + 0
13 Foundation 0x3477030b <redacted> + 86
14 UIKit 0x3834a925 <redacted> + 1844
15 UIKit 0x38349a7b <redacted> + 634
16 CoreFoundation 0x36ceb62f <redacted> + 714
17 UIKit 0x383497f5 <redacted> + 136
18 UIKit 0x384275e5 <redacted> + 60
19 UIKit 0x383b5cd7 <redacted> + 206
20 UIKit 0x383b5b6d <redacted> + 264
21 libdispatch.dylib 0x359e29f7 <redacted> + 30
22 UIKit 0x383b5a61 <redacted> + 92
23 UIKit 0x383bf0d5 <redacted> + 32
24 libdispatch.dylib 0x359e43f7 <redacted> + 42
25 UIKit 0x383bf0b1 <redacted> + 88
26 libdispatch.dylib 0x359df11f <redacted> + 10
27 libdispatch.dylib 0x359e2ecf <redacted> + 142
28 libdispatch.dylib 0x359e2dc1 <redacted> + 40
29 libdispatch.dylib 0x359e391d <redacted> + 184
30 libdispatch.dylib 0x359e3ac1 <redacted> + 84
31 libsystem_c.dylib 0x3aa76a11 <redacted> + 360
32 libsystem_c.dylib 0x3aa768a4 start_wqthread + 8
感谢任何帮助。 感谢。
更新：
不幸的是，这里似乎有多个错误。
在我的情况下，Mail Composer的崩溃不是由外观或一个引起的 属性字符串。我测试了所有可能的连接，但是我的代码崩溃了。
所以我开始逐行评论我的所有代码，并将其钉住：
这是In App Purchase代码。
我正在使用xamarin网站上的In App Purchase示例中的代码。
如果我使用SKProductRequest类评论此行：
productsRequest.Start（）;
MFMailComposer打开并完美运行！
所以我在最初的Xamarin示例项目中测试了MFMailComposer：
http://docs.xamarin.com/ios/tutorials/In-App_Purchasing http://docs.xamarin.com/@api/deki/files/3300/=InAppPurchaseSample.zip
我刚刚将此代码添加到NonConsumableViewController类：
/// <summary>
/// TEST MAIL COMPOSER BUG - START
/// </summary>
MFMailComposeViewController _mail;
void HandleFinished (object sender, MFComposeResultEventArgs e)
{
}
public void TestMailComposer ()
{
var button = UIButton.FromType(UIButtonType.RoundedRect);
button.Frame = new RectangleF(20f, 0f, 280f, 40f);
button.TouchUpInside += (object sender, EventArgs e) => {
if (MFMailComposeViewController.CanSendMail) {
_mail = new MFMailComposeViewController ();
_mail.SetSubject ("The Subject");
_mail.SetToRecipients (new [] {"the@recipient.com"});
_mail.SetMessageBody ("Some text to e-mail stuff too" +
"\n", false);
_mail.Finished += HandleFinished;
this.PresentViewController(_mail, true, null);
} else {
//handle not being able to send mail
UIAlertView alert = new UIAlertView ("Mail Alert", "Error:
Check your eMail configuration", null, "OK", null);
alert.Show ();
}
};
button.SetTitle("Button", UIControlState.Normal);
View.AddSubview(button);
}
///
/// TEST MAIL COMPOSER BUG - END
///
当我按下按钮时，它会挂起。
更新：
我尝试了6.0.2修补程序（抱歉等待，但我不得不将我的代码恢复到原始状态）。外观错误现在消失了。
SKProductRequest类的问题似乎不同而且不太紧急。它没有挂起，只是推迟了MF Mail作曲家的开放一段时间。但这似乎是一个无关的错误。
答案 0 :(得分：2)
这可能有所帮助（来自Xamarin bug）
cancelAttributes = new UITextAttributes();
//cancelAttributes.TextShadowOffset = new UIOffset(0, -1);
cancelAttributes.TextShadowColor = UIColor.White.ColorWithAlpha(0.5f);
cancelAttributes.TextColor = Resources.CancelButtonDisabled;
UIBarButtonItem.AppearanceWhenContainedIn(typeof(UISearchBar)).SetTitleTextAttributes(cancelAttributes, UIControlState.Disabled);
如果我的代码中有注释位，我会遇到问题，但如果注释掉则不会。你在使用UIAppearance吗？