当前，我有一个表格视图，该视图在有多个单元格时会滞后。当只有一个单元时，它运行平稳；但是，当填充多个单元格时，表视图的感觉很慢，有时会结结巴巴，并且不那么平滑。我删除了手势识别器，而是将其更改为didSelectRowAt，但是单元格中仍然存在滞后。这是单元格加载时的代码：
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if queryComplete == true {
if displayConvo == true {
let cell = tableView.dequeueReusableCell(withIdentifier: "messageCell", for: indexPath as IndexPath) as! messageTableViewCell
cell.profileImage.image = nil
cell.selectionStyle = UITableViewCell.SelectionStyle.none
var convoContent: messagesViewController.Convo
convoContent = convoList[indexPath.row]
convoContent.itemHeroID = "\(String(describing: convoContent.convoID))"
cell.name.heroID = "\(String(describing: convoContent.convoID))"
cell.lastMessage.text = convoContent.lastMessage
cell.backgroundColor = UIColor.clear
cell.postText.text = convoContent.postContent
if convoContent.revealedBool == true {
cell.profileImage.isHidden = false
cell.profileImage.heroID = "\(String(describing: convoContent.convoID))"
cell.name.text = convoContent.name
cell.timer.isHidden = true
if convoContent.profileImage == "nil" || convoContent.profileImage == nil {
let url = URL(string:"https://firebasestorage.googleapis.comasdjfjaisfdji")
let processor = RoundCornerImageProcessor(cornerRadius: cell.profileImage.frame.size.width / 2)
cell.profileImage.kf.setImage(with: url, placeholder: nil, options: [.processor(processor)])
}
else {
let url = URL(string: convoContent.profileImage!)
let processor = RoundCornerImageProcessor(cornerRadius: cell.profileImage.frame.size.width / 2)
cell.profileImage.kf.setImage(with: url, placeholder: nil, options: [.processor(processor)])
}
}
else {
cell.profileImage.isHidden = true
cell.timer.isHidden = false
cell.timer.isUserInteractionEnabled = false
cell.timer.heroID = "\(String(describing: convoContent.convoID))"
let postDuration = convoContent.timeOfDeletion! - Int(convoContent.time!)
let currentTime = Date().timeIntervalSince1970 * 1000
let difference = Int(round(Double(convoContent.timeOfDeletion! - Int(currentTime))))
let date = Date(timeIntervalSinceNow: TimeInterval(difference / 1000))
cell.name.text = String(timeToDelete(date: date as NSDate, numericDates: false))
let amountOfCircleCovered = (Double(((convoContent.timeOfDeletion!) - Int(currentTime))) / Double(postDuration)) * 100
var timerColor: UIColor?
switch amountOfCircleCovered {
case 0..<30:
timerColor = UIColor (red: 252/255, green: 110/255, blue: 81/255, alpha: 1)
case 30..<60:
timerColor = UIColor (red: 255/255, green: 215/255, blue: 0/255, alpha: 1)
case 60..<100:
timerColor = UIColor(red: 26/255, green: 152/255, blue: 252/255, alpha: 1.0)
default:
timerColor = UIColor(red: 26/255, green: 152/255, blue: 252/255, alpha: 1.0)
}
print(amountOfCircleCovered)
cell.timer.models = [ PieSliceModel(value: Double(100 - amountOfCircleCovered), color: UIColor(red: 220/255, green: 220/255, blue: 220/255, alpha: 1)),
PieSliceModel(value: Double(amountOfCircleCovered), color: timerColor!),
]
}
let lastMessageDate = Date(timeIntervalSince1970: TimeInterval(convoContent.timeOfLastMessage! / 1000))
cell.timeOfLastMessage.text = String(timeAgo(date: lastMessageDate as NSDate, numericDates: false))
return cell
}
else {
let cell = tableView.dequeueReusableCell(withIdentifier: "messageCell", for: indexPath as IndexPath) as! messageTableViewCell
cell.lastMessage.text = "No new messages"
return cell
}
}
else {
let cell = tableView.dequeueReusableCell(withIdentifier: "messageCell", for: indexPath as IndexPath) as! messageTableViewCell
print ("loading")
return cell
}
}
此外，我还尝试过移动单元格的某些方面，以便每次将它们放在单元格文件中时都可以重置：
override func awakeFromNib() {
super.awakeFromNib()
profileImage.cornerRadius = profileImage.frame.size.width / 2
profileImage.clipsToBounds = true
profileImage.layer.borderColor = UIColor.white.cgColor
profileImage.layer.borderWidth = 1
timer.innerRadius = 0
timer.outerRadius = timer.frame.width / 2
timer.animDuration = 0.0
timer.referenceAngle = 270
timer.backgroundColor = UIColor.white
postText.layer.zPosition = 1
if !UIAccessibility.isReduceTransparencyEnabled {
glossyView.backgroundColor = .clear
let blurEffect = UIBlurEffect(style: .regular)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
//always fill the view
blurEffectView.frame = self.glossyView.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
glossyView.addSubview(blurEffectView) //if you have more UIViews, use an insertSubview API to place it where needed
} else {
glossyView.backgroundColor = .black
}
timer.selectedOffset = 0
glossyView.clipsToBounds = true
glossyView.cornerRadius = 12.0
glossyView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
messageBackground.clipsToBounds = true
messageBackground.cornerRadius = 12.0
messageBackground.layer.maskedCorners = [.layerMinXMaxYCorner, .layerMaxXMaxYCorner]
// glossyView.roundCornersView(corners: [.topLeft, .topRight], radius: 12.0)
// messageBackground.roundCornersView(corners: [.bottomLeft,.bottomRight], radius: 12.0)
// Initialization code
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
}
override func prepareForReuse() {
profileImage.image = nil
timer.isHidden = true
timer.models = []
}
}
但是，当加载多个单元格时，表视图仍然滞后。我确保没有this link建议的手势识别器，并且还使用库来加载图像，所以我不确定为什么单元格仍然滞后。
答案 0 :(得分：1)
本质上，UI大大降低了性能。我为部分填充的圆圈的png图像切换了饼图CA图层，并删除了所有Hero动画。结果，应用程序和表格视图都变得更加流畅。