![](/img/trans.png)
[英]showing progress on imageview on customcell on uitableview
[英]UITableView CustomCell Reuse (ImageView in CustomCell)
我是 iOS 开发人员的新手,我对 UITableViewCell 有疑问。 我想这与出列可重用单元格有关。 我在我的自定义表格视图单元格中添加了一个 UIImageView,还添加了一个点击手势来制作喜欢/不喜欢 function(图像从空心(不喜欢)变为充满心(喜欢)作为点击和反转)。 问题是当我向下滚动时,一些单元格会被自动点击。 我发现了为什么会这样,但仍然不知道如何适当地修复它。 以下是我的代码,
视图控制器
import UIKit
struct CellData {
var title: String
var done: Bool
}
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var models = [CellData]()
private let tableView: UITableView = {
let table = UITableView()
table.register(TableViewCell.self, forCellReuseIdentifier: TableViewCell.identifier)
return table
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(tableView)
tableView.frame = view.bounds
tableView.delegate = self
tableView.dataSource = self
configure()
}
private func configure() {
self.models = Array(0...50).compactMap({
CellData(title: "\($0)", done: false)
})
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return models.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let model = models[indexPath.row]
guard let cell = tableView.dequeueReusableCell(withIdentifier: TableViewCell.identifier, for: indexPath) as? TableViewCell else {
return UITableViewCell()
}
cell.textLabel?.text = model.title
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
tableView.reloadData()
}
}
表格视图单元格
import UIKit
class TableViewCell: UITableViewCell {
let mainVC = ViewController()
static let identifier = "TableViewCell"
let likeImage: UIImageView = {
let imageView = UIImageView()
imageView.image = UIImage(systemName: "heart")
imageView.tintColor = .darkGray
imageView.isUserInteractionEnabled = true
imageView.translatesAutoresizingMaskIntoConstraints = false
return imageView
}()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
contentView.addSubview(likeImage)
layout()
//Tap Gesture Recognizer 실행하기
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didTapImageView(_:)))
likeImage.addGestureRecognizer(tapGestureRecognizer)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
}
override func prepareForReuse() {
super.prepareForReuse()
}
private func layout() {
likeImage.widthAnchor.constraint(equalToConstant: 30).isActive = true
likeImage.heightAnchor.constraint(equalToConstant: 30).isActive = true
likeImage.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
likeImage.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -20).isActive = true
}
@objc func didTapImageView(_ sender: UITapGestureRecognizer) {
if likeImage.image == UIImage(systemName: "heart.fill"){
likeImage.image = UIImage(systemName: "heart")
likeImage.tintColor = .darkGray
} else {
likeImage.image = UIImage(systemName: "heart.fill")
likeImage.tintColor = .systemRed
}
}
}
这个 gif 显示了它现在是如何工作的。 在此处输入图像描述
我尝试使用 CellData 结构中的“完成”属性来捕获 uiimageview 的状态但失败了(不知道如何以正确的方式使用它)。 如果有人可以提供帮助,我将非常高兴!
您已经发现问题出在细胞重复使用上。
当您出列要显示的单元格时,您已经根据您的数据设置了单元格标签的文本:
cell.textLabel?.text = model.title
您还需要告诉单元格是显示空心还是填充心形图像。
而且,当用户点击该图像时,您的单元格需要告诉 controller 更新数据 model 的.done
属性。
这可以通过协议/委托模式或更常见的方式(尤其是 Swift)使用闭包来完成。
这是对您发布的代码的快速修改......评论应该让您对发生的事情有一个很好的了解:
struct CellData {
var title: String
var done: Bool
}
class ShinViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var models = [CellData]()
private let tableView: UITableView = {
let table = UITableView()
table.register(ShinTableViewCell.self, forCellReuseIdentifier: ShinTableViewCell.identifier)
return table
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(tableView)
tableView.frame = view.bounds
tableView.delegate = self
tableView.dataSource = self
configure()
}
private func configure() {
self.models = Array(0...50).compactMap({
CellData(title: "\($0)", done: false)
})
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return models.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: ShinTableViewCell.identifier, for: indexPath) as! ShinTableViewCell
let model = models[indexPath.row]
cell.myLabel.text = model.title
// set the "heart" to true/false
cell.isLiked = model.done
// closure
cell.callback = { [weak self] theCell, isLiked in
guard let self = self,
let pth = self.tableView.indexPath(for: theCell)
else { return }
// update our data
self.models[pth.row].done = isLiked
}
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
}
}
class ShinTableViewCell: UITableViewCell {
// we'll use this closure to communicate with the controller
var callback: ((UITableViewCell, Bool) -> ())?
static let identifier = "TableViewCell"
let likeImageView: UIImageView = {
let imageView = UIImageView()
imageView.image = UIImage(systemName: "heart")
imageView.tintColor = .darkGray
imageView.isUserInteractionEnabled = true
imageView.translatesAutoresizingMaskIntoConstraints = false
return imageView
}()
let myLabel: UILabel = {
let v = UILabel()
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
// we'll load the heart images once in init
// instead of loading them every time they change
var likeIMG: UIImage!
var unlikeIMG: UIImage!
var isLiked: Bool = false {
didSet {
// update the image in the image view
likeImageView.image = isLiked ? likeIMG : unlikeIMG
// update the tint
likeImageView.tintColor = isLiked ? .systemRed : .darkGray
}
}
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
// make sure we load the heart images
guard let img1 = UIImage(systemName: "heart"),
let img2 = UIImage(systemName: "heart.fill")
else {
fatalError("Could not load the heart images!!!")
}
unlikeIMG = img1
likeIMG = img2
// add label and image view
contentView.addSubview(myLabel)
contentView.addSubview(likeImageView)
layout()
//Tap Gesture Recognizer 실행하기
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didTapImageView(_:)))
likeImageView.addGestureRecognizer(tapGestureRecognizer)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
}
override func prepareForReuse() {
super.prepareForReuse()
}
private func layout() {
// let's use the "built-in" margins guide
let g = contentView.layoutMarginsGuide
// image view bottom constraint
let bottomConstraint = likeImageView.bottomAnchor.constraint(equalTo: g.bottomAnchor)
// this will avoid auto-layout complaints
bottomConstraint.priority = .required - 1
NSLayoutConstraint.activate([
// constrain label leading
myLabel.leadingAnchor.constraint(equalTo: g.leadingAnchor),
// center the label vertically
myLabel.centerYAnchor.constraint(equalTo: g.centerYAnchor),
// constrain image view trailing
likeImageView.trailingAnchor.constraint(equalTo: g.trailingAnchor),
// constrain image view to 30 x 30
likeImageView.widthAnchor.constraint(equalToConstant: 30),
likeImageView.heightAnchor.constraint(equalTo: likeImageView.widthAnchor),
// constrain image view top
likeImageView.topAnchor.constraint(equalTo: g.topAnchor),
// activate image view bottom constraint
bottomConstraint,
])
}
@objc func didTapImageView(_ sender: UITapGestureRecognizer) {
// toggle isLiked (true/false)
isLiked.toggle()
// inform the controller, so it can update the data
callback?(self, isLiked)
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.