在我的iOS应用程序中，有一个带有tableview的视图。表格单元格是从远程服务器上的PHP文件加载的。我还在视图控制器上放了一个应该重新加载数据的NSTimer。
单元格包含可能在时间间隔内更改的信息。只有当细胞数量在一段时间间隔内没有变化时，这才能正常工作。如果按时间间隔添加单元格，则应用程序崩溃。
这是NSTimer的代码：
self.timer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(refrescar) userInfo:nil repeats:YES];
这是方法refrescar的代码：
- (void)refrescar {
total_actual =0;
total =0;
[self viewDidLoad];
}
我也试过这个：
- (void)refrescar {
total_actual =0;
total =0;
[self.tableView reloadData];
}
但该应用程序与其他代码[self viewDidLoad];
欢迎任何帮助。
错误日志：
2014-11-13 23:52:23.299 RestAppXXI[1552:607] -[NSNull length]: unrecognized selector sent to instance 0xcb6068
2014-11-13 23:52:23.429 RestAppXXI[1552:607] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull length]: unrecognized selector sent to instance 0xcb6068'
*** First throw call stack:
(
0 CoreFoundation 0x00b6a1e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x031588e5 objc_exception_throw + 44
2 CoreFoundation 0x00c07243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
3 CoreFoundation 0x00b5a50b ___forwarding___ + 1019
4 CoreFoundation 0x00b5a0ee _CF_forwarding_prep_0 + 14
5 UIKit 0x01fd2cc7 -[UILabel _textRectForBounds:limitedToNumberOfLines:includingShadow:] + 57
6 UIKit 0x01fd2b13 -[UILabel textRectForBounds:limitedToNumberOfLines:] + 85
7 UIKit 0x01fd662e -[UILabel _intrinsicSizeWithinSize:] + 173
8 UIKit 0x01fd6751 -[UILabel intrinsicContentSize] + 91
9 UIKit 0x024b07ef -[UIView(UIConstraintBasedLayout) _generateContentSizeConstraints] + 36
10 UIKit 0x024b0480 -[UIView(UIConstraintBasedLayout) _updateContentSizeConstraints] + 511
11 UIKit 0x024b67bf -[UIView(AdditionalLayoutSupport) updateConstraints] + 110
12 UIKit 0x01fd6579 -[UILabel updateConstraints] + 189
13 UIKit 0x024b6058 -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 239
14 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
15 UIKit 0x024b6157 __UIViewRecursionHelper + 40
16 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
17 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
18 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
19 UIKit 0x024b6157 __UIViewRecursionHelper + 40
20 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
21 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
22 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
23 UIKit 0x024b6157 __UIViewRecursionHelper + 40
24 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
25 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
26 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
27 UIKit 0x024b6157 __UIViewRecursionHelper + 40
28 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
29 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
30 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
31 UIKit 0x024b6157 __UIViewRecursionHelper + 40
32 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
33 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
34 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
35 UIKit 0x024b6157 __UIViewRecursionHelper + 40
36 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
37 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
38 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
39 UIKit 0x024b6157 __UIViewRecursionHelper + 40
40 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
41 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
42 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
43 UIKit 0x024b6157 __UIViewRecursionHelper + 40
44 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
45 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
46 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
47 UIKit 0x024b6157 __UIViewRecursionHelper + 40
48 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
49 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
50 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
51 UIKit 0x024b6157 __UIViewRecursionHelper + 40
52 CoreFoundation 0x00b0bc69 CFArrayApplyFunction + 57
53 UIKit 0x024b5ffc -[UIView(AdditionalLayoutSupport) _internalUpdateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 147
54 UIKit 0x024b61d6 -[UIView(AdditionalLayoutSupport) _updateConstraintsIfNeededAccumulatingViewsNeedingSecondPass:] + 122
55 UIKit 0x024aa878 __62-[UIWindow(UIConstraintBasedLayout) updateConstraintsIfNeeded]_block_invoke + 43
56 Foundation 0x02f0b68c -[NSISEngine withBehaviors:performModifications:] + 107
57 Foundation 0x02d9b3c5 -[NSISEngine withAutomaticOptimizationDisabled:] + 48
58 UIKit 0x024aa590 -[UIWindow(UIConstraintBasedLayout) updateConstraintsIfNeeded] + 225
59 UIKit 0x024aa467 -[UIWindow(UIConstraintBasedLayout) layoutSublayersOfLayer:] + 90
60 libobjc.A.dylib 0x0316a82b -[NSObject performSelector:withObject:] + 70
61 QuartzCore 0x0171a45a -[CALayer layoutSublayers] + 148
62 QuartzCore 0x0170e244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
63 QuartzCore 0x0170e0b0 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
64 QuartzCore 0x016747fa _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 294
65 QuartzCore 0x01675b85 _ZN2CA11Transaction6commitEv + 393
66 QuartzCore 0x01676258 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 92
67 CoreFoundation 0x00b3236e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
68 CoreFoundation 0x00b322bf __CFRunLoopDoObservers + 399
69 CoreFoundation 0x00b10254 __CFRunLoopRun + 1076
70 CoreFoundation 0x00b0f9d3 CFRunLoopRunSpecific + 467
71 CoreFoundation 0x00b0f7eb CFRunLoopRunInMode + 123
72 GraphicsServices 0x041945ee GSEventRunModal + 192
73 GraphicsServices 0x0419442b GSEventRun + 104
74 UIKit 0x01e18f9b UIApplicationMain + 1225
75 RestAppXXI 0x000305ed main + 141
76 libdyld.dylib 0x049eb6d9 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
答案 0 :(得分：0)
这与您的UITableView无关。这很可能来自您尝试访问的字符串，但它是nil。
答案 1 :(得分：-1)
用户异常断点要调试，你在NSNull对象上调用长度方法
为什么要使用NSTimer，您可以在从服务器获取响应后重新加载表