Question

我在具有两个集合视图的视图控制器中使用sizeForItemAtIndexPath函数。

如何在sizeForItemAtIndexPath函数中排除一个集合视图，或者如何在不更改任何内容的情况下获取原始单元格大小？

Answer 1

排除一个集合视图

 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.
  */    
}

获取原始单元格大小而不更改任何内容

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

假设您正在使用故事板，则可以将每个集合视图作为插座连接到视图控制器。 E.g

@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)
  }
}

SizeForItemAtIndexPath：获取标准尺寸的项目

2 个答案: