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[英]How to add supplementary header view for an empty section in collectionView custom layout
[英]How to add a header supplementary cell above other supplementary header cells In a collectionView custom layout
在更改下面,您將接近該結果。
對於Portrait,我更改了第0部分和第0項的xPosition
和像Cell width
對於風景,我更改了第0部分和項目0的xPosition
, yPosition
和像Cell width
。
我為Cell
應該是SuperView
中心做了一些邏輯。
override func prepare() {
dataSourceDidUpdate = false
if UIDevice.current.orientation == .landscapeLeft || UIDevice.current.orientation == .landscapeRight
{
if let sectionCount = collectionView?.numberOfSections, sectionCount > 0 {
for section in 0...sectionCount-1 {
let maxNum = max(section, sectionCount + 1)
let minNum = min(section, sectionCount + 1)
let difference = maxNum - minNum
var xPos = (Double(UIScreen.main.bounds.width) - (Double(difference) * CELL_WIDTH) - (Double(difference) * horizontalSpacing))
var yPos : Double = 35.0
if let rowCount = collectionView?.numberOfItems(inSection: section), rowCount > 0 {
for item in 0...rowCount-1 {
xPos = (Double(UIScreen.main.bounds.width) - (Double(difference) * CELL_WIDTH) - (Double(difference) * horizontalSpacing))
CELL_WIDTH = 100.0
let cellIndex = IndexPath(item: item, section: section)
if item == 0
{
portrait_Ypos = headerSpacing + 30
}
else
{
portrait_Ypos = portrait_Ypos + CELL_HEIGHT + verticalSpaing
}
yPos = portrait_Ypos
if section == 0 && item == 0
{
xPos = 20
yPos = 0.0
CELL_WIDTH = (Double(UIScreen.main.bounds.width)) - 40
}
let cellAttributes = UICollectionViewLayoutAttributes(forCellWith: cellIndex)
cellAttributes.frame = CGRect(x: xPos, y: yPos, width: CELL_WIDTH, height: CELL_HEIGHT)
xPos = (Double(UIScreen.main.bounds.width) - (Double(difference) * CELL_WIDTH) - (Double(difference) * horizontalSpacing))
CELL_WIDTH = 100.0
yPos = 35.0
// Determine zIndex based on cell type.
if section == 0 && item == 0 {
cellAttributes.zIndex = 4
} else if section == 0 {
cellAttributes.zIndex = 3
} else if item == 0 {
cellAttributes.zIndex = 2
} else {
cellAttributes.zIndex = 1
}
cellAttrsDictionary[cellIndex] = cellAttributes
}
}
}
}
let contentWidth = Double(collectionView!.numberOfSections) * CELL_WIDTH + (Double(collectionView!.numberOfSections - 1) * horizontalSpacing)
let contentHeight = Double(collectionView!.numberOfSections) * CELL_HEIGHT
self.contentSize = CGSize(width: contentWidth, height: contentHeight)
print("self.contentSizeself.contentSize ", self.contentSize)
}
else
{
if let sectionCount = collectionView?.numberOfSections, sectionCount > 0 {
for section in 0...sectionCount-1 {
var xPos = (Double(UIScreen.main.bounds.width) - CELL_WIDTH) / 2.0
if let rowCount = collectionView?.numberOfItems(inSection: section), rowCount > 0 {
for item in 0...rowCount-1 {
xPos = (Double(UIScreen.main.bounds.width) - CELL_WIDTH) / 2.0
CELL_WIDTH = 100.0
let cellIndex = IndexPath(item: item, section: section)
if section != 0
{
if item == 0
{
portrait_Ypos = portrait_Ypos + CELL_HEIGHT + headerSpacing
}
else
{
portrait_Ypos = portrait_Ypos + CELL_HEIGHT + verticalSpaing
}
}
else
{
if item == 0
{
portrait_Ypos = headerSpacing
xPos = 20
CELL_WIDTH = (Double(UIScreen.main.bounds.width)) - 40
}
else
{
portrait_Ypos = portrait_Ypos + CELL_HEIGHT + verticalSpaing
}
}
let cellAttributes = UICollectionViewLayoutAttributes(forCellWith: cellIndex)
cellAttributes.frame = CGRect(x: xPos, y: portrait_Ypos, width: CELL_WIDTH, height: CELL_HEIGHT)
xPos = (Double(UIScreen.main.bounds.width) - CELL_WIDTH) / 2.0
CELL_WIDTH = 100.0
if section == 0 && item == 0 {
cellAttributes.zIndex = 4
} else if section == 0 {
cellAttributes.zIndex = 3
} else if item == 0 {
cellAttributes.zIndex = 2
} else {
cellAttributes.zIndex = 1
}
cellAttrsDictionary[cellIndex] = cellAttributes
}
}
}
}
let contentWidth = UIScreen.main.bounds.width
let contentHeight = CGFloat(portrait_Ypos) + CGFloat(CELL_HEIGHT)
self.contentSize = CGSize(width: contentWidth, height: contentHeight)
print("sPort.contentSize ", self.contentSize)
}
}
不要為第0部分添加標題
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
var attributesInRect = [UICollectionViewLayoutAttributes]()
for cellAttributes in cellAttrsDictionary.values {
if rect.intersects(cellAttributes.frame) {
attributesInRect.append(cellAttributes)
let celIndPth = cellAttributes.indexPath
if celIndPth.section != 0
{
if celIndPth.item == 0
{
if let supplementaryAttributes = layoutAttributesForSupplementaryView(ofKind: UICollectionElementKindSectionHeader, at: cellAttributes.indexPath) {
attributesInRect.append(supplementaryAttributes)
}
}
}
}
}
return attributesInRect
}
override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
return cellAttrsDictionary[indexPath]!
}
單元格
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! RulesCollectionViewCell
cell.backgroundColor = UIColor.clear
cell.layer.borderColor = UIColor(red: 83/255, green: 50/255, blue: 129/255, alpha: 1.0).cgColor
cell.layer.borderWidth = 1.0
cell.txtLbl.text = values[indexPath.section][indexPath.row]
cell.txtLbl.textAlignment = .center
cell.txtLbl.textColor = UIColor.white
if indexPath.section == 0 && indexPath.row == 0
{
cell.backgroundColor = UIColor.white
cell.txtLbl.textColor = UIColor.red
}
cell.layer.cornerRadius = 5
cell.alpha = 1.0
return cell
}
數組聲明
let values = [["Main Header"],["a","b","c","d","e","f"], ["a","b","c"], ["a","b","c","d"], ["a","b","c","d","e","f"]]
產量
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