UITableView/UIScrollView how to automatically know when ContentSize changes?
The answer is actually simple using KVO (Key Value Observing);
- (id)initWithFrame:(CGRect)frame tableView:(UITableView *)tableView{ // .... [self.tableView addObserver:self forKeyPath:@"contentSize" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld | NSKeyValueObservingOptionPrior context:NULL]; // ....}- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if ([keyPath isEqualToString:@"contentSize"]) { // Do something }}I am not sure about the flags yet though.
For those who don't like KVO:
- (void)setContentSize:(CGSize)contentSize { [super setContentSize:contentSize]; // Do something.}Yeah, just use super to access the parent method. This assume you subclass UIScrollview/TableView/CollectionView