如何在 Swift 中创建水平滚动 UICollectionView? [英] How do I create a horizontal scrolling UICollectionView in Swift?

问题描述

如何制作一个水平滚动的 collectionView 来填充跨行而不是向下的单元格?

我希望有 5 列和 3 行，但是当有超过 15 个项目时，我希望它滚动到下一页.我在这方面遇到了很多麻烦.

解决方案

选项 1 - 推荐

为您的收藏视图使用自定义布局.这是执行此操作的正确方法，它使您可以很好地控制您希望单元格如何填充集合视图.

这是来自raywenderlich"的

*添加"按钮只是将另一个数字添加到 myArray 并重新加载集合视图以演示它在 myArray

<小时>

编辑 - 将项目分组到页面中:

var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]让行 = 3让 columnsInPage = 5var itemsInPage: Int { return columnsInPage*rows }var columns: Int { return myArray.count%itemsInPage <= columnsInPage ?((myArray.count/itemsInPage)*columnsInPage) + (myArray.count%itemsInPage) : ((myArray.count/itemsInPage)+1)*columnsInPage }覆盖 func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) ->诠释{返回列*行}覆盖 func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) ->UICollectionViewCell {let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)让 t = indexPath.item/itemsInPage让 i = indexPath.item/rows - t*columnsInPage让 j = indexPath.item % 行让 item = (j*columnsInPage+i) + t*itemsInPage保护项

How can I make a horizontal scrolling collectionView that fills up cells going across the rows rather than down the columns?

I want there to 5 columns and 3 rows but when there is more than 15 items I want it to scroll to the next page. I'm having a lot of trouble getting this going.

解决方案

Option 1 - Recommended

Use custom layouts for your collection view. This is the right way to do this and it gives you a lot of control over how you want your cells to fill the collection view.

Here is a UICollectionView Custom Layout Tutorial from "raywenderlich"

---

Option 2

This is more like a hackish way of doing what you want. In this method you can access your data source in an order to simulate the style you need. I'll explain it in the code:

var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
let rows = 3
let columnsInFirstPage = 5
// calculate number of columns needed to display all items
var columns: Int { return myArray.count<=columnsInFirstPage ? myArray.count : myArray.count > rows*columnsInFirstPage ? (myArray.count-1)/rows + 1 : columnsInFirstPage }

override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {        
    return columns*rows
}

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)
    //These three lines will convert the index to a new index that will simulate the collection view as if it was being filled horizontally
    let i = indexPath.item / rows
    let j = indexPath.item % rows         
    let item = j*columns+i

    guard item < myArray.count else {
        //If item is not in myArray range then return an empty hidden cell in order to continue the layout
        cell.hidden = true
        return cell
    }
    cell.hidden = false

    //Rest of your cell setup, Now to access your data You need to use the new "item" instead of "indexPath.item"
    //like: cell.myLabel.text = "(myArray[item])"

    return cell
}

Here is this code in action:

*The "Add" button just adds another number to myArray and reloads the collection view to demonstrate how it would look with different number of items in myArray

---

Edit - Group items into pages:

var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
let rows = 3
let columnsInPage = 5
var itemsInPage: Int { return columnsInPage*rows }
var columns: Int { return myArray.count%itemsInPage <= columnsInPage ? ((myArray.count/itemsInPage)*columnsInPage)  + (myArray.count%itemsInPage) : ((myArray.count/itemsInPage)+1)*columnsInPage }

override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {        
    return columns*rows
}

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)

    let t = indexPath.item / itemsInPage
    let i = indexPath.item / rows - t*columnsInPage
    let j = indexPath.item % rows      
    let item = (j*columnsInPage+i) + t*itemsInPage

    guard item < myArray.count else {
        cell.hidden = true
        return cell
    }
    cell.hidden = false

    return cell
}

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