IOS KVO没有在delloc中移除导致奔溃

1.背景

为了监听tableview的移动

[_tableView addObserver:self forKeyPath:@"contentOffset" options:NSKeyValueObservingOptionNew context:nil];
2.问题

奔溃报错Attempting to load the view of a view controller while it is deallocating is not allowed and may result in undefined behavior

3.解决

- (void)dealloc
   {
       [_tableView removeObserver:self forKeyPath:@"contentOffset" context:nil];
   }