我在静态表视图中添加了一些 textField 和 textView 。代码很好，并且运行在 xcode 6.4 / ios 8。 * 但是它抛出了我无法跟踪的异常。现在我在xcode 7.2上调试代码（swift2.2）
我尝试了符号和例外断点，但没有运气:(
以下是崩溃的堆栈跟踪，提前感谢您的宝贵帮助。
2015-12-14 16:07:07.989 TuteMate[3380:90711] -[NSNull length]: unrecognized selector sent to instance 0x10ccc6af0
来自特殊断点：
CoreFoundation`-[NSObject(NSObject) doesNotRecognizeSelector:]:
-> 0x10504e3c0 <+0>: pushq %rbp
0x10504e3c1 <+1>: movq %rsp, %rbp
0x10504e3c4 <+4>: pushq %r15
0x10504e3c6 <+6>: pushq %r14
0x10504e3c8 <+8>: pushq %rbx
0x10504e3c9 <+9>: pushq %rax
0x10504e3ca <+10>: movq %rdx, %r14
0x10504e3cd <+13>: movq %rdi, %rbx
0x10504e3d0 <+16>: movq 0x216c79(%rip), %rsi ; "class"
0x10504e3d7 <+23>: callq *0x229e1b(%rip) ; (void *)0x000000010730b800: objc_msgSend
0x10504e3dd <+29>: movq %rax, %rdi
0x10504e3e0 <+32>: movq %rbx, %rsi
0x10504e3e3 <+35>: movq %r14, %rdx
0x10504e3e6 <+38>: callq 0x10504ed00 ; __CFFullMethodName
0x10504e3eb <+43>: movq %rax, %r14
0x10504e3ee <+46>: leaq 0x23fdeb(%rip), %r15 ; @"%@: unrecognized selector sent to instance %p"
0x10504e3f5 <+53>: movl $0x3, %edi
0x10504e3fa <+58>: xorl %eax, %eax
0x10504e3fc <+60>: movq %r15, %rsi
0x10504e3ff <+63>: movq %r14, %rdx
0x10504e402 <+66>: movq %rbx, %rcx
0x10504e405 <+69>: callq 0x104fe2560 ; CFLog
0x10504e40a <+74>: leaq 0x22b90f(%rip), %rax ; kCFAllocatorSystemDefault
0x10504e411 <+81>: movq (%rax), %rdi
0x10504e414 <+84>: xorl %esi, %esi
0x10504e416 <+86>: xorl %eax, %eax
0x10504e418 <+88>: movq %r15, %rdx
0x10504e41b <+91>: movq %r14, %rcx
0x10504e41e <+94>: movq %rbx, %r8
0x10504e421 <+97>: callq 0x104f35190 ; CFStringCreateWithFormat
0x10504e426 <+102>: movq %rax, %rdi
0x10504e429 <+105>: callq 0x104f33580 ; CFMakeCollectable
0x10504e42e <+110>: movq %rax, %rbx
0x10504e431 <+113>: movq %rbx, %rdi
0x10504e434 <+116>: nop
0x10504e435 <+117>: nopl (%rax)
0x10504e439 <+121>: leaq 0x225300(%rip), %rax ; __CFOASafe
0x10504e440 <+128>: cmpb $0x0, (%rax)
0x10504e443 <+131>: je 0x10504e459 ; <+153>
0x10504e445 <+133>: movl $0x3, %edi
0x10504e44a <+138>: xorl %edx, %edx
0x10504e44c <+140>: xorl %ecx, %ecx
0x10504e44e <+142>: xorl %r8d, %r8d
0x10504e451 <+145>: movq %rbx, %rsi
0x10504e454 <+148>: callq 0x10501b150 ; __CFRecordAllocationEvent
0x10504e459 <+153>: movq %rbx, %rdi
0x10504e45c <+156>: callq 0x1050a3696 ; symbol stub for: _objc_rootAutorelease
0x10504e461 <+161>: movq 0x218370(%rip), %rdi ; (void *)0x00000001052690d0: NSException
0x10504e468 <+168>: leaq 0x234fb1(%rip), %rcx ; NSInvalidArgumentException
0x10504e46f <+175>: movq (%rcx), %rdx
0x10504e472 <+178>: movq 0x216c4f(%rip), %rsi ; "exceptionWithName:reason:userInfo:"
0x10504e479 <+185>: xorl %r8d, %r8d
0x10504e47c <+188>: movq %rax, %rcx
0x10504e47f <+191>: callq *0x229d73(%rip) ; (void *)0x000000010730b800: objc_msgSend
0x10504e485 <+197>: movq %rax, %rdi
0x10504e488 <+200>: callq 0x1050a3738 ; symbol stub for: objc_exception_throw
0x10504e48d <+205>: nopl (%rax)
更新堆栈跟踪
2015-12-14 16:45:58.932 TuteMate[4000:109943] -[NSNull length]: unrecognized selector sent to instance 0x105b72af0
2015-12-14 16:46:02.651 TuteMate[4000:109943] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull length]: unrecognized selector sent to instance 0x105b72af0'
*** First throw call stack:
(
0 CoreFoundation 0x000000010594de65 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000107bfddeb objc_exception_throw + 48
2 CoreFoundation 0x000000010595648d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x00000001058a390a ___forwarding___ + 970
4 CoreFoundation 0x00000001058a34b8 _CF_forwarding_prep_0 + 120
5 CoreFoundation 0x0000000105825dfa CFStringCompareWithOptionsAndLocale + 202
6 Foundation 0x0000000106019e37 -[NSString compare:options:range:] + 29
7 UIKit 0x00000001069c4e6f -[UIPhysicalKeyboardEvent _matchesKeyCommand:] + 303
8 UIKit 0x00000001068e93fd -[UIResponder _keyCommandForEvent:target:] + 364
9 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
10 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
11 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
12 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
13 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
14 UIKit 0x00000001068e95b2 -[UIResponder _keyCommandForEvent:target:] + 801
15 UIKit 0x00000001066fb91a -[UIApplication _handleKeyUIEvent:] + 948
16 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
17 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
18 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
19 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
20 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
21 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
22 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
23 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
24 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
25 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
26 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
27 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
28 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
29 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
30 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
31 UIKit 0x00000001068e9e53 -[UIResponder _handleKeyUIEvent:] + 79
32 UIKit 0x00000001066fb2cd -[UIApplication handleKeyUIEvent:] + 79
33 UIKit 0x0000000106991c83 -[UIKeyboardImpl _handleKeyEvent:executionContext:] + 66
34 UIKit 0x0000000106b91cde -[UIKeyboardLayoutStar completeRetestForTouchUp:timestamp:interval:executionContext:] + 3356
35 UIKit 0x00000001069a0bbd __28-[UIKeyboardLayout touchUp:]_block_invoke + 228
36 UIKit 0x00000001070ed724 -[UIKeyboardTaskQueue continueExecutionOnMainThread] + 332
37 UIKit 0x00000001069a0ace -[UIKeyboardLayout touchUp:] + 236
38 UIKit 0x00000001069a1614 -[UIKeyboardLayout touchesEnded:withEvent:] + 348
39 UIKit 0x000000010674b49b -[UIWindow _sendTouchesForEvent:] + 835
40 UIKit 0x000000010674c1d0 -[UIWindow sendEvent:] + 865
41 UIKit 0x00000001066fab66 -[UIApplication sendEvent:] + 263
42 UIKit 0x00000001066d4d97 _UIApplicationHandleEventQueue + 6844
43 CoreFoundation 0x0000000105879a31 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
44 CoreFoundation 0x000000010586f95c __CFRunLoopDoSources0 + 556
45 CoreFoundation 0x000000010586ee13 __CFRunLoopRun + 867
46 CoreFoundation 0x000000010586e828 CFRunLoopRunSpecific + 488
47 GraphicsServices 0x000000010c9daad2 GSEventRunModal + 161
48 UIKit 0x00000001066da610 UIApplicationMain + 171
49 TuteMate 0x000000010500128d main + 109
50 libdyld.dylib 0x000000010932c92d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
更新 没有其他viewWillAppeaer，didAppear ......方法实现了！
override func viewDidLoad() {
super.viewDidLoad()
title = "Profile Edit"
}
表viewDelegates是
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Potentially incomplete method implementation.
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete method implementation.
// Return the number of rows in the section.
return 3
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = super.tableView(tableView, cellForRowAtIndexPath: indexPath)
return cell
}
答案 0 :(得分：5)
@dip：从你的评论看来，你需要学习一些非常重要的调试知识，那就是：你认为的一切都是假的。当你说＆＃34;我没有存储null或类似的东西时，我们知道是假的。第二个最重要的规则：信任证据。
证据是一条消息＆＃34;长度：＆＃34;这是一个NSString方法被发送到[NSNull null]。你存储[NSNull null]的某个地方你应该存储一个字符串。第三条调试规则：你做错了什么。没有神秘的小鬼试图让你感到不安，这是你的代码错了。因此，找出存储[NSNull null]的位置。来自JSON解析器的任何东西总是一个很好的候选者。
答案 1 :(得分：-1)
可能的解决方案：
我的问题是由于我无意中点击了属性检查器中的“键盘命令”控件而导致的。
点击此处查看我的回复： https://stackoverflow.com/a/36187611/5006807
我希望它有所帮助....