自定义CollectionViewCell

创建了带有自定义CollectionViewCell的CollectionView应用。

添加了一个按钮"select all/deselect all" 对所有cell都有效，为了实现这点我用了一个循环：

for(customCollectionViewCell* cell in self.collectionView){  
    // some code
}

报警：

Collection expression type "UICollectionView *" many not correspond to "countByEnumeratingWithStage:objects:count"

然后我编译程序单击按钮，应用崩溃了：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UICollectionView countByEnumeratingWithState:objects:count:]: unrecognized selector sent to instance 0x7973e00'