SizeForItemAtIndexPath：獲取項目標準大小

Question

我在具有兩個集合視圖的視圖控制器中使用sizeForItemAtIndexPath函數。

如何排除sizeForItemAtIndexPath函數中的一個集合視圖，或者如何在不更改任何內容的情況下獲取原始單元大小？

Answer 1

• 排除一個集合視圖

  func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
       // to exclude one collection view 
       if collectionView == collectionViewOne {}// first 
      if collectionView.tag == number(you set before){}// second 
  
      // to get the original cell size without changing anything 
      //let yourSize = collectionViewLayout.itemSize 
      //return collectionViewLayout.itemSize // if you have set it globally, 
      /* 
      But you can not get it, because itemSize is a property of UICollectionViewFlowLayout. 
  
      And you can't cast collectionViewLayout to UICollectionViewFlowLayout Class which is kind of UICollectionViewLayout Class . 
  
      Thats not how inheritance works. 
      */  
  } 
  

• 得到原始細胞大小不做改變

  let indexPath = IndexPath(item: number(you choose), section: number(you choose, 0 or 1)) 
  let layout = UICollectionViewFlowLayout() // you set 
  // got the size 
  // more generally, if you have set layout per item through delegate. 
  let size = self.collectionView(collectionViewOne, layout: layout, sizeForItemAtIndexPath: indexPath) 
  // or try this ,if you have configured globally 
  let itemSize = layout.itemSize 
  

Answer 2

假設您使用故事板，您可以將每個收藏視圖作爲視圖控制器的出口連接。例如

@IBOutlet weak var collectionViewOne: UICollectionView! 
@IBOutlet weak var collectionViewTwo: UICollectionView! 

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
    if collectionView == collectionViewOne { 
    // Do nothing, and set default size. 
    return layout.itemSize 
    } else { 
    //Set size here along with other setup. 
    return CGSize(width: 150, height: 150) 
    } 
}