我在代码中添加了一个观察者,然后在dealloc和viewWillDisappear中将其移除,但仍然出现错误提示。
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x167e5980 of class MyController2 was deallocated while key value observers were still registered with it.
Current observation info: <NSKeyValueObservationInfo 0x16719f90> ( <NSKeyValueObservance 0x16719fb0: Observer: 0x167e5980, Key path: dataContainer.report, Options: <New: YES, Old: YES, Prior: NO> Context: 0x0, Property: 0x1677df30> )'
我创建了一个控制器MyController
,并从它派生了一个新的控制器MyController2
。现在我在MyController2
中添加了KVO。
- (void)viewDidLoad {
[super viewDidLoad];
[self addObserver:self forKeyPath:@"dataContainer.report" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:nil];
}
然后在observeValueForKeyPath方法中:
- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context {
id oldC = [change objectForKey:NSKeyValueChangeOldKey];
id newC = [change objectForKey:NSKeyValueChangeNewKey];
if([keyPath isEqualToString:@"dataContainer.report"]) {
if (oldC != newC) {
//Remove Observer
[self removeObserver:self forKeyPath:@"dataContainer.report" context:nil];
[self updateDataContainer];
[self reportView];
}
}
}
然后我尝试在viewWillDisappear和dealloc中删除观察器:
- (void)dealloc {
@try{
[self removeObserver:self forKeyPath:@"dataContainer.report" context:nil];
}@catch(id anException){
}
}
-(void) viewWillDisappear:(BOOL)animated{
@try{
[self removeObserver:self forKeyPath:@"dataContainer.report" context:nil];
}@catch(id anException){
}
[super viewWillDisappear:animated];
}
我看了很多帖子,它们都说同一件事情:你需要移除观察者。我试图从两个地方移除观察者,但仍然遇到了问题。
dataContainer.inspectionReport
键路径添加了观察者,但您的代码将键路径显示为dataContainer.report
。 - Midhun MP