有人能告诉我我改编自 iOS 5 Developer's Cookbook 的以下代码有什么问题吗
- (void) startMonitoringUbiquitousDocumentsFolder
{
// Remove any existing query – stored in local instance variable
if (alertQuery) [alertQuery stopQuery];
// Search for all file names
alertQuery.predicate = [NSPredicate predicateWithFormat: @"NSMetadataItemFSNameKey == '*'"];
alertQuery.searchScopes = [NSArray arrayWithObject:
NSMetadataQueryUbiquitousDocumentsScope];
// Subscribe to query updates
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(alertUserToUpdates:)
name:NSMetadataQueryDidUpdateNotification
object:nil];
[alertQuery startQuery];
}
- (void) alertUserToUpdates
{
NSLog(@"Contents changed in ubiquitous documents folder");
UIAlertView *alertView = [[UIAlertView alloc]
initWithTitle:@"Home Monitor"
message:@"Something's going on."
delegate:nil
cancelButtonTitle:@"OK"
otherButtonTitles:@"Check Recording", nil];
[alertView show];
[self stopMonitoringUbiquitousDocumentsFolder];
}
我收到一个异常,提示选择器 alertUserToUpdates: 无法识别。为什么它不能识别明明就在它旁边的方法?
2013-04-29 18:07:22.458 eyeFun[8231:907] -[RGPViewController alertUserToUpdates:]: unrecognized selector sent to instance 0x1fd506a0
2013-04-29 18:07:22.462 eyeFun[8231:907] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[RGPViewController alertUserToUpdates:]: unrecognized selector sent to instance 0x1fd506a0'
*** First throw call stack:
(0x337eb3e7 0x3b4e6963 0x337eef31 0x337ed64d 0x33745208 0x3373c349 0x34053b7f 0x340ab327 0x3373c349 0x337b810f 0x37880de9 0x340fa657 0x337c0857 0x337c0503 0x337bf177 0x3373223d 0x337320c9 0x3731133b 0x3564e2b9 0x465b5 0x3b913b20)
libc++abi.dylib: terminate called throwing an exception