我正在从 Firebase 读取数据，然后在表格 View 单元格中显示这些数据。还有一个本地存储的文件，其中包含每个单元格的已读/未读状态。该文件包含 Firebase 中每个子项的键，我将其与每个单元格中的数据进行匹配。
基本上，如果单元格有一个也在文件中找到的键，那么这个数据被用户认为是“读取”的。但是，如果单元格具有在本地文件中没有等效项的键，则此数据被视为“未读”。
到目前为止，一切正常。然后我为每个单元格添加了两个滑动功能。先标记为已读，再标记为未读。当标记为“已读”时，滑动会调用一个函数，将单元格的键写入本地文件。相反，当标记为“未读”时，滑动会调用另一个从本地文件中删除 key 的函数。这也很完美。
但是，在滑动时，我还必须更改单元格背景颜色以反射(reflect)“已读”或“未读”。这导致了一个问题，因为单元格被重新加载以供重用......在我的例子中，我在重新加载之前得到了 7 个单元格。
这意味着如果我有超过 7 个单元格，并且我将某些内容标记为“已读”，我最终会更改多个单元格的背景颜色。文件写入工作正常......只是背景颜色被复制了。
我在 editActionsForRowAt 函数中更改颜色如下:
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let Action2 = UITableViewRowAction(style: .default, title: "Mark Read", handler: { (action, indexPath) in
//函数在设置颜色之前继续做一些事情...
if filteredMessageIDforSwipe.count == 0 {
let selectedCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
selectedCell.contentView.backgroundColor = UIColor(hexString: "#ffffff")
请注意，我不是在选择一个单元格...而是轻扫，然后尝试更改被轻扫的单元格的单元格背景颜色。
显然，我只希望我滑动的单元格改变颜色，而不是另一个单元格(如果我有超过 7 个单元格)。
谢谢!
N.
编辑:我已经按照下面的建议修改了 editActionsForRowAt，但没有效果。
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
selectedRowIndexForReadUnread = indexPath.row
let Action2 = UITableViewRowAction(style: .default, title: "Mark Read", handler: { (action, indexPath) in
if filteredMessageIDforSwipe.count == 0 && selectedRowIndexForReadUnread = indexPath.row {
let selectedCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
selectedCell.contentView.backgroundColor = UIColor(hexString: "#ffffff")
编辑:作为引用，这里是 editActionsForRowAt 函数...Action2 和 Action5 是相关的。
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
selectedRowIndexForReadUnread = indexPath.row
if tableView == self.Nomination2SearchTableView {
let Action1 = UITableViewRowAction(style: .default, title: "Select", handler: { (action, indexPath) in
self.Nomination2SearchTableView.isHidden = true
self.Nomination2TableView.isHidden = false
NominationState = "Active"
let SearchObject: Nomination2SearchModel
SearchObject = Nomination2SearchList[indexPath.row]
userIDStringforNominationSearch = SearchObject.UserIDString!
let FullName = SearchObject.Full_Name
self.FullNameLabel.isHidden = false
self.FullNameLabel.text = "Showing " + FullName! + "'s Shout Outs"
self.LoadDataFromNominationafterSearch()
self.ActiveButton.setTitleColor(.orange, for: .normal)
let banner = NotificationBanner(title: "Tip", subtitle: "Swipe to select a user.", style: .info)
banner.haptic = .none
banner.show()
//We are setting the editor mode to the opposite of what is displayed in the tableview, because EditorMode text is what is displayed when you swipe the cell.
// EditorMode = "Set to Complete"
})
return [Action1]
}
if tableView == self.Nomination2TableView{
if NominationState == "Active" {
let Action2 = UITableViewRowAction(style: .default, title: "Mark Read", handler: { (action, indexPath) in
let searchObject9: Nomination2Model
searchObject9 = Nomination2List[indexPath.row]
let messageIDKey = searchObject9.key
let filename = self.getDocumentsDirectory().appendingPathComponent("output.txt")
do {
let textStringFromFile = try String(contentsOf: filename, encoding: .utf8)
var result: [(messageID: String, readStatus: String)] = []
// var indexCount = result.count
let rows = textStringFromFile.components(separatedBy: "\n")
for row in rows {
let columns = row.components(separatedBy: ",")
result.append((columns[0], columns[1]))
}
filteredMessageIDforSwipe = result.filter { $0.messageID == (messageIDKey) }
}
catch{
}
if filteredMessageIDforSwipe.count == 0 {
let selectedCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
// let selectedCellForReadMessages:UITableViewCell = self.Nomination2TableView.cellForRow(at: indexPath)! as! Nomination2TableViewCell
selectedCell.contentView.backgroundColor = UIColor(hexString: "#ffffff")
// let myReadCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
// myReadCell.NominationNameLabel.textColor = UIColor.lightGray
// myReadCell.NominationTextLabel.textColor = UIColor.lightGray
let NominationObject: Nomination2Model
NominationObject = Nomination2List[indexPath.row]
nominationKeyForWhenCellSelected = NominationObject.key
self.writeFile()
// self.removeRowFromFile()
}
if filteredMessageIDforSwipe.count > 0 {
let alert = UIAlertController(title: "Failure",
message: "Shout-out is already read!",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default))
self.present(alert, animated: true, completion: nil)
}
})
let Action5 = UITableViewRowAction(style: .default, title: "Mark Unread", handler: { (action, indexPath) in
let searchObject9: Nomination2Model
searchObject9 = Nomination2List[indexPath.row]
let messageIDKey = searchObject9.key
let filename = self.getDocumentsDirectory().appendingPathComponent("output.txt")
do {
let textStringFromFile = try String(contentsOf: filename, encoding: .utf8)
var result: [(messageID: String, readStatus: String)] = []
// var indexCount = result.count
let rows = textStringFromFile.components(separatedBy: "\n")
for row in rows {
let columns = row.components(separatedBy: ",")
result.append((columns[0], columns[1]))
}
filteredMessageIDforSwipe = result.filter { $0.messageID == (messageIDKey) }
}
catch{
}
if filteredMessageIDforSwipe.count > 0 {
let selectedCell:UITableViewCell = tableView.cellForRow(at: indexPath)!
selectedCell.contentView.backgroundColor = UIColor(hexString: "#fcf0e5")
// let myCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
// myCell.NominationNameLabel.textColor = UIColor.orange
// myCell.NominationTextLabel.textColor = UIColor.black
let NominationObject: Nomination2Model
NominationObject = Nomination2List[indexPath.row]
nominationKeyForWhenCellSelected = NominationObject.key
// self.writeFile()
self.removeRowFromFile()
}
if filteredMessageIDforSwipe.count == 0 {
let alert = UIAlertController(title: "Failure",
message: "Shout-out is already unread!",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default))
self.present(alert, animated: true, completion: nil)
}
})
Action2.backgroundColor = UIColor.lightGray
Action5.backgroundColor = UIColor.blue
return[Action2, Action5]
}
if NominationState == "Approve"{
let Action3 = UITableViewRowAction(style: .default, title: NominationState, handler: { (action, indexPath) in
let searchObject9: Nomination2Model
searchObject9 = Nomination2List[indexPath.row]
ForName = searchObject9.ForName!
FromName = searchObject9.FromName!
ForWhat = searchObject9.ForWhat!
key = searchObject9.key!
ForUserID = searchObject9.ForUserID!
FromUserID = searchObject9.FromUserID!
PointsGifted = searchObject9.PointsGifted!
NominationText = searchObject9.NominationText!
ImageNameNominations = searchObject9.ImageNameString!
ImageURLNominations = searchObject9.ImageURL!
databaseReference = Database.database().reference()
databaseReference.child("Users").child(FromUserID).observeSingleEvent(of: DataEventType.value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let CurrentPointsRedeemed = value?["Points_Redeemed"] as? Int
let CurrentPointsBalance = value? ["Points_Balance"] as? Int
let NewPointsRedeemed = CurrentPointsRedeemed! + PointsGifted
let NewPointsBalance = CurrentPointsBalance! - PointsGifted
if NewPointsBalance >= 0{
databaseReference.child("Users").child(FromUserID).updateChildValues(["Points_Redeemed": NewPointsRedeemed])
databaseReference.child("Users").child(FromUserID).updateChildValues(["Points_Balance": NewPointsBalance])
self.postToFirebase()
self.giftPoints()
self.pendingCount()
Nomination2List.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
}
if NewPointsBalance <= 0{
let alert = UIAlertController(title: "Nominations",
message: "Not Enough Points for approval",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default))
self.present(alert, animated: true, completion: nil)
}
})
})
Action3.backgroundColor = UIColor.blue
return[Action3]
}
//here
//Action2.backgroundColor = UIColor.blue
//return[Action2]
else{
return [UITableViewRowAction]()
}
}
else {
return [UITableViewRowAction]()
}
}
最佳答案
表格 View 单元格得到重用，这就是其他单元格的背景颜色发生变化的原因。
hacking with swift 上有一段不错的代码片段这正是你需要的。我也在我自己的项目中使用这个片段。
所以在你的情况下它看起来像这样:
let backgroundView = UIView()
backgroundView.backgroundColor = UIColor(red:0.94, green:0.94, blue:0.94, alpha:1.0)
cell.selectedBackgroundView = backgroundView
用这个替换你的代码，我认为它会没问题。希望这会有所帮助。
编辑:
要仅更改滑动单元格的颜色，您可以尝试在 if 语句之后插入一个 else 语句。你可以试试这个:
let selectedCell = self.Nomination2TableView.cellForRow(at: indexPath) as! Nomination2TableViewCell
if filteredMessageIDforSwipe.count == 0 {
selectedCell.contentView.backgroundColor = UIColor(hexString: "#ffffff")
} else {
selectedCell.contentView.backgroundColor = UIColor.white
//or whatever the color of the background is by default
}
如果这不能解决问题，请告诉我!
编辑 2:
我在一个(过于简化的)小测试应用程序中重新创建了您问题的核心。回顾一下，这就是我所理解的问题的核心:您想设置在表格 View 中滑动的单元格的颜色。您还希望它们在您重新打开应用程序时保持该颜色，并防止其他单元格因单元格重复使用而变色。
在下面的解决方案中，我没有使用与您使用的完全相同的对象和变量，因为如果没有您的完整代码，将很难重新创建这些对象和变量。相反，这是您可以在自己的解决方案中实现的逻辑。因此，您似乎将选定的单元格 indexPaths 保留在 filteredMessageIDforSwipe 中 - 因此您应该遍历该数组并为具有相应索引路径的单元格设置颜色。在调用 for 循环之前设置默认单元格背景颜色很重要。
这是我的示例 ViewController:
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet weak var tableView: UITableView!
let userDefaults = UserDefaults.standard
let testArray = ["Test1", "Test2", "Test3", "Test4", "Test5", "Test6", "Test7", "Test8", "Test9", "Test10", "Test11", "Test12", "Test13", "Test14", "Test15", "Test16", "Test17", "Test18", "Test19", "Test20"]
var selectedCellIndexPaths = [Int]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
if let values = userDefaults.value(forKey: "IndexPathsArray") as? Array<Int> {
selectedCellIndexPaths = values
}
print("selected", selectedCellIndexPaths)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return testArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
cell.textLabel?.text = testArray[indexPath.row]
cell.backgroundColor = UIColor.white
for indx in selectedCellIndexPaths {
if indexPath.row == indx {
cell.backgroundColor = UIColor.red
}
}
return cell
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let cell = tableView.cellForRow(at: indexPath)
let action = UITableViewRowAction(style: .default, title: "Mark Read") { (action, indexPath) in
cell?.backgroundColor = UIColor.red
self.selectedCellIndexPaths.append(indexPath.row)
self.userDefaults.set(self.selectedCellIndexPaths, forKey: "IndexPathsArray")
print(self.selectedCellIndexPaths)
}
return [action]
}
如果您需要进一步的帮助，请告诉我!
关于swift - 当表格中的行数超过 7 行时，多个表格 View 单元格的背景颜色会发生变化，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54418311/