如何处理 UICollectionView 的多项选择，它会在滑动时更改数据？
How to handle multiple selection for a UICollectionView, which changes data on swipe?
我在 UIViewController 上有一个 UICollectionView，它可以在滑动时更改数据，它也有搜索功能。我更改数组值并在每次滑动时重新加载 UICollectionView。现在，当我尝试实现多选时，滚动时选择会发生变化。
我使用的代码是，
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if searchIsOn {
return filteredTeamNames.count
}
else{
return teamNames.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifierTwo, for: indexPath as IndexPath) as! HouseCells
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 6
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let stringURL: String = singleComponent["icon_profile"]!
cell.teamImage.sd_setImage(with: URL(string: stringURL), placeholderImage: UIImage(named: "demo"))
cell.teamNameLabel.text = singleComponent["username"]
//to check for bg color
let idValue: Int = Int(singleComponent["id"]!)!
print(idValue)
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let idTempValue: Int = Int(singleComponent["id"]!)!
print(idTempValue)
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
}
数组 selectedTeamIDs 包含唯一编号，因此如果用户单击特定索引，我会将相应的 ID 添加到 selectedTeamIDs 数组并在 cellForItemAt 中，我正在检查是否当前索引值的 id 存在于 selectedTeamIDs 数组中，如果是，我正在更改单元格的背景颜色。但是我的代码不起作用，滚动时选择发生变化。我在哪里缺少逻辑？
首先不要reloadData在didSelectItemAt方法里面，移除reload行
自定义单元格中的第二个 class HouseCells（顺便说一下 class 的名称应该是单数）
添加此代码
override var isSelected: Bool {
didSet {
if isSelected {
backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
layer.borderWidth = 2.0
layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
}
}
同时从 cellForItemAt 方法中删除此代码
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
并且在您的 didSelectItemAt 方法中您现在不需要此代码：
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
给定的代码是正确的，除了 else 部分中两行代码的问题，如
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if searchIsOn {
return filteredTeamNames.count
}
else{
return teamNames.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifierTwo, for: indexPath as IndexPath) as! HouseCells
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 6
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let stringURL: String = singleComponent["icon_profile"]!
cell.teamImage.sd_setImage(with: URL(string: stringURL), placeholderImage: UIImage(named: "demo"))
cell.teamNameLabel.text = singleComponent["username"]
//to check for bg color
let idValue: Int = Int(singleComponent["id"]!)!
print(idValue)
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else { cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor.clear.cgColor
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let idTempValue: Int = Int(singleComponent["id"]!)!
print(idTempValue)
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
}
希望这个回答对某人有用！
我在 UIViewController 上有一个 UICollectionView，它可以在滑动时更改数据，它也有搜索功能。我更改数组值并在每次滑动时重新加载 UICollectionView。现在，当我尝试实现多选时，滚动时选择会发生变化。
我使用的代码是，
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if searchIsOn {
return filteredTeamNames.count
}
else{
return teamNames.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifierTwo, for: indexPath as IndexPath) as! HouseCells
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 6
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let stringURL: String = singleComponent["icon_profile"]!
cell.teamImage.sd_setImage(with: URL(string: stringURL), placeholderImage: UIImage(named: "demo"))
cell.teamNameLabel.text = singleComponent["username"]
//to check for bg color
let idValue: Int = Int(singleComponent["id"]!)!
print(idValue)
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let idTempValue: Int = Int(singleComponent["id"]!)!
print(idTempValue)
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
}
数组 selectedTeamIDs 包含唯一编号，因此如果用户单击特定索引，我会将相应的 ID 添加到 selectedTeamIDs 数组并在 cellForItemAt 中，我正在检查是否当前索引值的 id 存在于 selectedTeamIDs 数组中，如果是，我正在更改单元格的背景颜色。但是我的代码不起作用，滚动时选择发生变化。我在哪里缺少逻辑？
首先不要reloadData在didSelectItemAt方法里面，移除reload行
自定义单元格中的第二个 class HouseCells（顺便说一下 class 的名称应该是单数）
添加此代码
override var isSelected: Bool {
didSet {
if isSelected {
backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
layer.borderWidth = 2.0
layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
}
}
同时从 cellForItemAt 方法中删除此代码
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else {
cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
}
并且在您的 didSelectItemAt 方法中您现在不需要此代码：
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
给定的代码是正确的，除了 else 部分中两行代码的问题，如
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if searchIsOn {
return filteredTeamNames.count
}
else{
return teamNames.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifierTwo, for: indexPath as IndexPath) as! HouseCells
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 6
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let stringURL: String = singleComponent["icon_profile"]!
cell.teamImage.sd_setImage(with: URL(string: stringURL), placeholderImage: UIImage(named: "demo"))
cell.teamNameLabel.text = singleComponent["username"]
//to check for bg color
let idValue: Int = Int(singleComponent["id"]!)!
print(idValue)
if selectedTeamIDs.contains(idValue) {
cell.backgroundColor = UIColor(red:0/255, green:0/255, blue:0/255, alpha:1.0)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor(red:56/255, green:192/255, blue:201/255, alpha:1.0).cgColor
} else { cell.backgroundColor = UIColor(red:26/255, green:26/255, blue:26/255, alpha:0.4)
cell.layer.borderWidth = 2.0
cell.layer.borderColor = UIColor.clear.cgColor
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
var singleComponent = [String : String]()
if searchIsOn {
singleComponent = self.filteredTeamNames[indexPath.item]
} else {
singleComponent = self.teamNames[indexPath.item]
}
let idTempValue: Int = Int(singleComponent["id"]!)!
print(idTempValue)
if !selectedTeamIDs.contains(idTempValue) {
selectedTeamIDs.append(idTempValue)
}
print(selectedTeamIDs)
middleSectionCollView.reloadData()
}
希望这个回答对某人有用！