Swift 3:无法以编程方式正确地在 Collectionview 标头上创建标签? [英] Swift 3: Cant programmatically create label on Collectionview header properly?

问题描述

好的，所以我在这里使用 Swift 3 并且我是 uicollectionviews 的新手.我正在尝试以编程方式将标签添加为我的集合视图中标题 UICollectionReusableView 的子视图.我已经像任何其他视图一样添加了标签，但我一生都无法将标签居中放置在标题上.

Alright, so Im working in Swift 3 here and Im new to uicollectionviews. I am trying to programmatically add a label as a subview of a header UICollectionReusableView in my collection view. I have added the label like any other view, but I cant for the life of me CENTER the label on the header.

这里是我在自定义header类中的标签代码，在storyboard中添加到header中:

Here is my label code in the custom header class, which is added to the header in the storyboard:

let pointsLabel = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.customInit()
    }


    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)!
        self.customInit()
    }

    func customInit() {

        //center inside content
        pointsLabel.frame = CGRect(x: 0, y: 0, width: self.bounds.width, height: 100)
    pointsLabel.center = CGPoint(x: self.bounds.width * 0.5, y: self.bounds.height * 0.5)
    pointsLabel.textColor = UIColor.darkGray
    pointsLabel.textAlignment = .center

        pointsLabel.text = "Testing 123"
        pointsLabel.font = UIFont(name: "Montserrat", size: 30)
        self.addSubview(pointsLabel)

    }

我的 Collectionview 确实有两边的边距:

My Collectionview does have a margin on either side:

self.collectionView.contentInset = UIEdgeInsets(top: 0, left: 32.5, bottom: 0, right: 32.5)

然而，这只会影响标题视图的大小，这意味着标签仍应以 header.bounds.width * 0.5 为中心.我将文本对齐居中，但文本向左倾斜:

However that should just affect the size of the header view, meaning the label should still be centered at the header.bounds.width * 0.5. And I centered the text alignment, yet the text is skewed to the left:

如果有帮助，我的收藏视图位于消息应用扩展程序中，但我不知道这会如何改变事情.这里有什么问题?

If it helps, my collection view is within an message app extension, but again I don't know how that would change things. What is wrong here?

即使有:

pointsLabel.frame = CGRect(x: 0, y: 0, width: self.bounds.width, height: 100)
    //pointsLabel.center = CGPoint(x: self.bounds.width * 0.8, y: self.bounds.height * 0.5)
        pointsLabel.center = self.center
        pointsLabel.textColor = UIColor.darkGray
        pointsLabel.backgroundColor = UIColor.blue

或者将我的宽度更改为更小，我得到:

Or changing my width to less, I get:

为什么?

推荐答案

如果你有页眉和页脚所以你可以用下面的代码替换 viewForSupplementaryElementOfKind 函数

If you have both header and footer so You may replace viewForSupplementaryElementOfKind function with below code

 func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

       switch kind {
        case UICollectionElementKindSectionHeader:

            let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier:
            headerId, for: indexPath) as! CustomHeader
            return header

        default:
            return UIHeaderView()
        }
}

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