ios - 向 ray wenderlich Pinterest 布局添加自定义标题
<p><p>我使用了 Ray Wenderlich 提供的 Pinterest 布局文件，并完美地实现了所需的单元格布局，但是在我添加自定义标题的 CollectionViewController 上，我想在自定义标题下方添加 Pinterest 层。<br/>
但是 Pinterest 层覆盖了自定义 header ，我再也找不到自定义 header 。</p>
<p>任何关于我如何解决这个问题的建议将不胜感激。</p>
<p>Pinterest 布局文件如下:</p>
<pre><code>import UIKit
protocol CustomLayoutDelegate: class {
// 1. Method to ask the delegate for the height of the image
func collectionView(_ collectionView:UICollectionView, heightForPhotoAtIndexPath indexPath:IndexPath) -> CGFloat
}
class CustomLayout: UICollectionViewFlowLayout {
//1. Pinterest Layout Delegate
weak var delegate: CustomLayoutDelegate!
//2. Configurable properties
fileprivate var numberOfColumns = 2
fileprivate var cellPadding: CGFloat = 5
//3. Array to keep a cache of attributes.
fileprivate var cache = ()
//4. Content height and size
fileprivate var contentHeight: CGFloat = 0
fileprivate var contentWidth: CGFloat {
guard let collectionView = collectionView else {
return 0
}
let insets = collectionView.contentInset
return collectionView.bounds.width - (insets.left + insets.right)
}
override var collectionViewContentSize: CGSize {
return CGSize(width: contentWidth, height: contentHeight)
}
override func prepare() {
// 1. Only calculate once
guard cache.isEmpty == true, let collectionView = collectionView else {
return
}
// 2. Pre-Calculates the X Offset for every column and adds an array to increment the currently max Y Offset for each column
let columnWidth = contentWidth / CGFloat(numberOfColumns)
var xOffset = ()
for column in 0 ..< numberOfColumns {
xOffset.append(CGFloat(column) * columnWidth)
}
var column = 0
var yOffset = (repeating: 0, count: numberOfColumns)
// 3. Iterates through the list of items in the first section
for item in 0 ..< collectionView.numberOfItems(inSection: 0) {
let indexPath = IndexPath(item: item, section: 0)
// 4. Asks the delegate for the height of the picture and the annotation and calculates the cell frame.
let photoHeight = delegate.collectionView(collectionView, heightForPhotoAtIndexPath: indexPath)
let height = cellPadding * 2 + photoHeight
let frame = CGRect(x: xOffset, y: yOffset, width: columnWidth, height: height)
let insetFrame = frame.insetBy(dx: cellPadding, dy: cellPadding)
// 5. Creates an UICollectionViewLayoutItem with the frame and add it to the cache
let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)
attributes.frame = insetFrame
cache.append(attributes)
// 6. Updates the collection view content height
contentHeight = max(contentHeight, frame.maxY)
yOffset = yOffset + height
column = column < (numberOfColumns - 1) ? (column + 1) : 0
}
}
override func layoutAttributesForElements(in rect: CGRect) -> ? {
var visibleLayoutAttributes = ()
// Loop through the cache and look for items in the rect
for attributes in cache {
if attributes.frame.intersects(rect) {
visibleLayoutAttributes.append(attributes)
}
}
return visibleLayoutAttributes
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
return cache
}
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>您必须在附加第一项之前为您的标题附加一个属性</p>
<p>除此之外，首先从您的页眉高度开始设置 yOffset</p>
<pre><code>var yOffset =
</code></pre>
<p>在第 3 节中 indexPath 之后的节之间添加此代码</p>
<pre><code> if item == 0 {
let headerAttributes = UICollectionViewLayoutAttributes(forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, with: indexPath)
headerAttributes.frame = CGRect(x: 0, y: 0, width: yourHeaderWidth, height: yourHeaderHeight)
cache.append(headerAttributes)
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - 向 ray wenderlich Pinterest 布局添加自定义标题，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/51134275/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/51134275/
</a>
</p>
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