我有一个包含3个可折叠部分的表格视图。用户只能选择第3部分中的行，选择时该行变为绿色。但是，当此部分折叠时，所有选择都将被忘记，而当我重新打开该部分时，通常第一行始终为绿色（尽管不应如此）。有时候，其他部分在不应该使用时也会变成绿色-不确定我错了吗？
// Number of table sections
func numberOfSections(in tableView: UITableView) -> Int {
return 3
}
// Set the number of rows
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if (self.expandedSectionHeaderNumber == section) {
// If markscheme, create the markscheme format
if (section == 2)
{
return self.markschemeRows.count
}
else
{
let arrayOfItems = self.sectionItems[section] as! NSArray
return arrayOfItems.count
}
} else {
return 0;
}
}
// Set titles for sections
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
if (self.sectionNames.count != 0) {
return self.sectionNames[section] as? String
}
return ""
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 44.0;
}
func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat{
return 0;
}
func tableView(_ tableView: UITableView, willDisplayHeaderView view: UIView, forSection section: Int) {
//recast your view as a UITableViewHeaderFooterView
let header: UITableViewHeaderFooterView = view as! UITableViewHeaderFooterView
header.contentView.backgroundColor = UIColor.darkGray
header.textLabel?.textColor = UIColor.white
if let viewWithTag = self.view.viewWithTag(kHeaderSectionTag + section) {
viewWithTag.removeFromSuperview()
}
let headerFrame = self.view.frame.size
let theImageView = UIImageView(frame: CGRect(x: headerFrame.width - 32, y: 13, width: 18, height: 18));
theImageView.image = UIImage(named: "Chevron-Dn-Wht")
theImageView.tag = kHeaderSectionTag + section
header.addSubview(theImageView)
// make headers touchable
header.tag = section
let headerTapGesture = UITapGestureRecognizer()
headerTapGesture.addTarget(self, action: #selector(CaseViewController.sectionHeaderWasTouched(_:)))
header.addGestureRecognizer(headerTapGesture)
}
// Load the table data
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tableCell", for: indexPath) as! CustomTableCell
let section = self.sectionItems[indexPath.section] as! NSArray
cell.textLabel?.textColor = UIColor.black
cell.selectionStyle = .none
//cell.backgroundColor = .white
// Get the data from different arrays depending on the section
if indexPath.section == 2 {
cell.textData?.text = markschemeRows[indexPath.row]
} else {
cell.textData?.text = section[indexPath.row] as! String
}
return cell
}
func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
if indexPath.section == 0{
if indexPath.row == 0{
return nil
}
}
else if indexPath.section == 1{
if indexPath.row == 0{
return nil
}
}
return indexPath
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.selectRow(at: indexPath, animated: true, scrollPosition: .none)
let cell = tableView.cellForRow(at: indexPath)
cell?.backgroundColor = .green
}
func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
let cell = tableView.cellForRow(at: indexPath)
if (cell?.backgroundColor == .green)
{
cell?.backgroundColor = .white
}
}
// MARK: - Expand / Collapse Methods
@objc func sectionHeaderWasTouched(_ sender: UITapGestureRecognizer) {
let headerView = sender.view as! UITableViewHeaderFooterView
let section = headerView.tag
let eImageView = headerView.viewWithTag(kHeaderSectionTag + section) as? UIImageView
if (self.expandedSectionHeaderNumber == -1) {
self.expandedSectionHeaderNumber = section
tableViewExpandSection(section, imageView: eImageView!)
} else {
if (self.expandedSectionHeaderNumber == section) {
tableViewCollapeSection(section, imageView: eImageView!)
} else {
let cImageView = self.view.viewWithTag(kHeaderSectionTag + self.expandedSectionHeaderNumber) as? UIImageView
tableViewCollapeSection(self.expandedSectionHeaderNumber, imageView: cImageView!)
tableViewExpandSection(section, imageView: eImageView!)
}
}
}
func tableViewCollapeSection(_ section: Int, imageView: UIImageView) {
let sectionData = self.sectionItems[section] as! NSArray
self.expandedSectionHeaderNumber = -1;
if (sectionData.count == 0) {
return;
} else {
UIView.animate(withDuration: 0.4, animations: {
imageView.transform = CGAffineTransform(rotationAngle: (0.0 * CGFloat(Double.pi)) / 180.0)
})
var indexesPath = [IndexPath]()
// If markscheme, different number needed
if (section == 2)
{
for i in 0 ..< markschemeRows.count {
let index = IndexPath(row: i, section: section)
indexesPath.append(index)
}
}
else
{
for i in 0 ..< sectionData.count {
let index = IndexPath(row: i, section: section)
indexesPath.append(index)
}
}
self.tableView!.beginUpdates()
self.tableView!.deleteRows(at: indexesPath, with: UITableView.RowAnimation.fade)
self.tableView!.endUpdates()
}
}
func tableViewExpandSection(_ section: Int, imageView: UIImageView) {
let sectionData = self.sectionItems[section] as! NSArray
if (sectionData.count == 0) {
self.expandedSectionHeaderNumber = -1;
return;
} else {
UIView.animate(withDuration: 0.4, animations: {
imageView.transform = CGAffineTransform(rotationAngle: (180.0 * CGFloat(Double.pi)) / 180.0)
})
var indexesPath = [IndexPath]()
// If markscheme, create the markscheme format
if (section == 2)
{
for i in 0 ..< markschemeRows.count {
let index = IndexPath(row: i, section: section)
indexesPath.append(index)
}
}
else
{
for i in 0 ..< sectionData.count {
let index = IndexPath(row: i, section: section)
indexesPath.append(index)
}
}
self.expandedSectionHeaderNumber = section
self.tableView!.beginUpdates()
self.tableView!.insertRows(at: indexesPath, with: UITableView.RowAnimation.fade)
self.tableView!.endUpdates()
}
}
答案 0 :(得分：0)
这里要理解的关键是， 单元格被重用 （当您说
时）let cell = tableView.dequeueReusableCell(withIdentifier: "tableCell", for: indexPath) as! CustomTableCell
dequeueReusableCell基本上重用了先前加载的UITableViewCell，在您的情况下，您将单元格的背景色更改为绿色
要更好地理解这一概念，请考虑阅读诸如this之类的有关重用单元格的文章
代码更改
考虑到以上几点，您应该怎么做
var backgroundColors = [UIColor](repeating: UIColor.white, count: 10)
您必须在模型中保存颜色的状态（理想情况下，您应该创建自定义结构）
现在在cellForRowAt中添加
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tableCell", for: indexPath) as! CustomTableCell
.
.
cell.backgroundColor = backgroundColors[indexPath.row]
// **EDIT**
let cellShouldBeSelected = backgroundColors[indexPath.row] == .green
if cellShouldBeSelected {
tableView.selectRow(at: indexPath, animated: false, scrollPosition: .none)
}
.
.
return cell
}
您的didSelectRowAt和didDeselectRowAt应该更新模型
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.backgroundColors[indexPath.row] = .green
tableView.reloadRows(at: [indexPath], with: .none)
}
func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
if (self.backgroundColors[indexPath.row] == .green) {
self.backgroundColors[indexPath.row] = .white
tableView.reloadRows(at: [indexPath], with: .none)
}
}
第二次思考
解决方案2 （推荐）
从您的评论中，我看到您一次只需要选择一个单元格，假设保留一个backgroundColors数组是一个坏主意。
为所选索引声明一个整数
// -1 representing nothing is selected in the beginning
var selectedRow = -1
现在您的cellForRowAt看起来像
let cell = tableView.dequeueReusableCell(withIdentifier: "tableCell", for: indexPath) as! CustomTableCell
.
.
if indexPath.section == 2, indexPath.row == self.selectedRow {
cell.backgroundColor = .green
} else {
cell.backgroundColor = .white
}
.
.
return cell
}
还有您的didSelectRowAt
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if indexPath.section == 2 {
self.selectedRow = indexPath.row
tableView.reloadSections([2], with: .automatic)
}
}
现在您可以完全删除didDeselectRowAt