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[英]How to limit number of cells display of UICollectionView - swift
[英]UICollectionView in Swift 3 display additional Cells in sections
這是我在Swift 3中的代碼
class BSViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
let reuseIdentifier = "cell" // also enter this string as the cell identifier in the storyboard
var items = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14","15","16"]
// MARK: - UICollectionViewDataSource protocol
// tell the collection view how many cells to make
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
// make a cell for each cell index path
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// get a reference to our storyboard cell
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! MyCollectionViewCell
// Use the outlet in our custom class to get a reference to the UILabel in the cell
cell.myLabel.text = self.items[indexPath.item]
cell.backgroundColor = UIColor.cyan // make cell more visible in our example project
return cell
}
// MARK: - UICollectionViewDelegate protocol
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
// handle tap events
print("You selected cell #\(indexPath.item)!")
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
if self.items.count % 3 > 0 {
print(self.items.count % 3)
return (self.items.count/3)+1
}
else {
return self.items.count/3
}
}
private func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
var collectionViewSize = collectionView.frame.size
collectionViewSize.width = collectionViewSize.width/3.0 //Display Three elements in a row.
collectionViewSize.height = collectionViewSize.height/4.0
return collectionViewSize
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let view = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionFooter, withReuseIdentifier: "Footer", for: indexPath)
// configure footer view
return view
}
}
結果,它為我顯示6行,每行有3個單元格,並且必須是6行,並且每行包含3個單元格,期望最后一行必須有2個剩余單元格。
結果不正確
[XXX]
[XXX]
[XXX]
[XXX]
[XXX]
[XXX]
正確的結果
[XXX]
[XXX]
[XXX]
[XXX]
[XXX]
[XX]
這確實是一個數學問題,Swift沒有任何問題。
您必須正確進行兩個計算:
您可以在numberOfSections
計算所需的節數。 您的計算是正確的。
您可以在numberOfItemsInSection
中的給定部分中計算要顯示多少個單元格。 您此處的計算不正確,因為您沒有進行計算; 您總是返回3。因此,每個部分將始終包含3個單元格。
要解決此問題,您需要進行計算以計算部分截面。 以下是解決此問題的一種方法:
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return ((section + 1) * 3) <= self.items.count ? 3 : self.items.count % 3
}
順便說一句,如果您有16個項目(例如您的示例),則最后一節應包含1個單元格。
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