我如何知道UICollectionView已经完全加载？ [英] How do I know that the UICollectionView has been loaded completely?

问题描述

每当UICollectionView被完全加载时，我必须做一些操作，即当时应该调用所有的UICollectionView的数据源/布局方法。我怎么知道？有没有任何代理方法来知道UICollectionView加载状态？

解决方案

  //在viewDidLoad 
 [self.collectionView addObserver：self forKeyPath：@contentSize选项：NSKeyValueObservingOptionOld上下文：NULL]; 
 
  - （void）observeValueForKeyPath：（NSString *）keyPath ofObject：（id）object change：（NSDictionary *）更改上下文：（void *）context 
 {
 //当reloadData完成
} 
 
  - （void）dealloc 
 {
 [self.collectionView removeObserver：self forKeyPath：@contentSizecontext：空值]; 
} 
  

I have to do some operation whenever UICollectionView has been loaded completely, i.e. at that time all the UICollectionView's datasource / layout methods should be called. How do I know that?? Is there any delegate method to know UICollectionView loaded status?

解决方案

// In viewDidLoad
[self.collectionView addObserver:self forKeyPath:@"contentSize" options:NSKeyValueObservingOptionOld context:NULL];

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary  *)change context:(void *)context
{
    // You will get here when the reloadData finished 
}

- (void)dealloc
{
    [self.collectionView removeObserver:self forKeyPath:@"contentSize" context:NULL];
}

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