我有以下方法为当前中心视图控制器选择行：
- (void)_updateSelection
{
[self.tableView reloadData];
[_viewControllers enumerateKeysAndObjectsUsingBlock:^(NSString *path, UIViewController *viewController, BOOL *stop) {
if (viewController == self.revealSideViewController.rootViewController) {
NSInteger row = [self indexOfPath:path];
if (row != NSNotFound && row < [self.tableView numberOfRowsInSection:0]) {
[self.tableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:row inSection:0] animated:NO scrollPosition:UITableViewScrollPositionNone];
}
*stop = YES;
}
}];
}
如您所见，我有几项检查以确保一切有效。根据表视图，该行在该部分的范围内。大多数时候，这很好用。因为在调用reloadData时表视图一直在忽略它的选择，所以当我需要进行更改时，我会调用它。我也在viewWillAppear:中称呼它。这是偶尔崩溃的地方。
崩溃的输出是：
*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayM objectAtIndex:]: index 2 beyond bounds [0 .. 0]'
*** First throw call stack:
(
0 CoreFoundation 0x041415e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x03ec48b6 objc_exception_throw + 44
2 CoreFoundation 0x040e24e6 -[__NSArrayM objectAtIndex:] + 246
3 UIKit 0x022aaa5c -[UITableView cellForRowAtIndexPath:] + 235
4 UIKit 0x022ad6f0 -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1320
5 UIKit 0x022ad983 -[UITableView selectRowAtIndexPath:animated:scrollPosition:] + 63
6 The City 0x000073a2 __40-[TCMainMenuController _updateSelection]_block_invoke + 578
7 CoreFoundation 0x041cb13a __65-[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:]_block_invoke + 106
8 CoreFoundation 0x041cb03e -[__NSDictionaryM enumerateKeysAndObjectsWithOptions:usingBlock:] + 190
9 CoreFoundation 0x0412f525 -[NSDictionary enumerateKeysAndObjectsUsingBlock:] + 53
10 The City 0x0000713c -[TCMainMenuController _updateSelection] + 220
11 The City 0x00006999 -[TCMainMenuController viewWillAppear:] + 105
12 UIKit 0x022e2bfa -[UIViewController _setViewAppearState:isAnimating:] + 419
13 UIKit 0x022e3108 -[UIViewController __viewWillAppear:] + 114
14 UIKit 0x022e40c7 -[UIViewController viewWillMoveToWindow:] + 387
15 UIKit 0x02227384 -[UIView(Hierarchy) _willMoveToWindow:withAncestorView:] + 619
16 UIKit 0x02232f60 -[UIView(Internal) _addSubview:positioned:relativeTo:] + 470
17 UIKit 0x022269ed -[UIView(Hierarchy) insertSubview:belowSubview:] + 55
18 The City 0x0034c6b4 -[PPRevealSideViewController pushViewController:onDirection:withOffset:animated:forceToPopPush:completion:] + 2260
19 The City 0x000afc9c -[TCRootViewController pushViewController:onDirection:withOffset:animated:forceToPopPush:completion:] + 428
20 The City 0x0034bc9c -[PPRevealSideViewController pushViewController:onDirection:withOffset:animated:completion:] + 236
21 The City 0x0034b8a4 -[PPRevealSideViewController pushViewController:onDirection:animated:completion:] + 212
22 The City 0x0034b7b5 -[PPRevealSideViewController pushViewController:onDirection:animated:] + 149
23 The City 0x000af832 -[TCRootViewController showMenu] + 162
24 The City 0x00009a13 +[App showMenu] + 83
25 The City 0x00008611 -[TCMainMenuController showMenu:] + 81
26 libobjc.A.dylib 0x03ed6874 -[NSObject performSelector:withObject:withObject:] + 77
27 UIKit 0x021cd0c2 -[UIApplication sendAction:to:from:forEvent:] + 108
28 UIKit 0x024a1c9b -[UIBarButtonItem(UIInternal) _sendAction:withEvent:] + 139
29 libobjc.A.dylib 0x03ed6874 -[NSObject performSelector:withObject:withObject:] + 77
30 UIKit 0x021cd0c2 -[UIApplication sendAction:to:from:forEvent:] + 108
31 UIKit 0x021cd04e -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
32 UIKit 0x022c50c1 -[UIControl sendAction:to:forEvent:] + 66
33 UIKit 0x022c5484 -[UIControl _sendActionsForEvents:withEvent:] + 577
34 UIKit 0x022c4733 -[UIControl touchesEnded:withEvent:] + 641
35 UIKit 0x0220a51d -[UIWindow _sendTouchesForEvent:] + 852
36 UIKit 0x0220b184 -[UIWindow sendEvent:] + 1232
37 UIKit 0x021dee86 -[UIApplication sendEvent:] + 242
38 UIKit 0x021c918f _UIApplicationHandleEventQueue + 11421
39 CoreFoundation 0x040ca83f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
40 CoreFoundation 0x040ca1cb __CFRunLoopDoSources0 + 235
41 CoreFoundation 0x040e729e __CFRunLoopRun + 910
42 CoreFoundation 0x040e6ac3 CFRunLoopRunSpecific + 467
43 CoreFoundation 0x040e68db CFRunLoopRunInMode + 123
44 GraphicsServices 0x04f8b9e2 GSEventRunModal + 192
45 GraphicsServices 0x04f8b809 GSEventRun + 104
46 UIKit 0x021cbd3b UIApplicationMain + 1225
47 The City 0x000026ad main + 141
48 libdyld.dylib 0x0468270d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
使用调试器，我可以看到-visibleCells虽然不是空的，但没有我想要选择的单元格（但它应该除了它在屏幕外）。
答案 0 :(得分：0)
您的问题源于当您将控制权返回到运行循环时运行-reloadData的事实。你现在这样做的方式会导致崩溃，因为在你离开那个区块之后才会执行-reloadData。
解决此问题的一种方法是调度要在下一个运行循环上运行的块：
[self.tableView reloadData];
dispatch_async(dispatch_get_main_thread(), ^{
[_viewControllers enumerateKeysAndObjectsUsingBlock:^(NSString *path, UIViewController *viewController, BOOL *stop) {
if (viewController == self.revealSideViewController.rootViewController) {
NSInteger row = [self indexOfPath:path];
if (row != NSNotFound && row < [self.tableView numberOfRowsInSection:0]) {
[self.tableView selectRowAtIndexPath:[NSIndexPath indexPathForRow:row inSection:0] animated:NO scrollPosition:UITableViewScrollPositionNone];
}
*stop = YES;
}
}];
});
请参阅此讨论：How to tell when UITableVIew has completed ReloadData?