我试图创建一个tableview控制器，其中每个单元格都有一个渐变作为背景。
所以我的方法是下面的代码，它设置了正确的颜色，但滚动时颜色显示为随机设置。
我不知道错误在哪里。 textLabels将正确设置但颜色不正确。
import UIKit
class ResourceOverViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
let reuseIdentifier = "OverViewCell"
@IBOutlet weak var prototypeCell: UITableViewCell!
@IBOutlet weak var tableView:UITableView!
var resourceInMissions:[ResourceInMission] = [ResourceInMission]()
var whiteRussian:Int64 = Int64()
var Caipirinha:[String] = [String]()
var Avails:[CAGradientLayer] = [CAGradientLayer]()
override func viewDidLoad() {
self.tableView.register(UITableViewCell.self, forCellReuseIdentifier: reuseIdentifier)
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
setView()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return Caipirinha.count
}
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
print(indexPath)
cell.textLabel?.backgroundColor = UIColor.clear
cell.textLabel?.isOpaque = true
cell.isOpaque = true
var gradient = Avails[indexPath.row]
gradient.frame = cell.bounds
cell.textLabel?.layer.insertSublayer(gradient, at: 0)
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier, for: indexPath)
cell.textLabel?.text = Caipirinha[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){
var index: IndexPath = indexPath
let cell = tableView.cellForRow(at: indexPath)
whiteRussian = resourceInMissions[indexPath.row].getID()
guard let vc = UIStoryboard(name:"Main", bundle:nil).instantiateViewController(withIdentifier: "ShowResource") as UIViewController? else {
print("Could not instantiate view controller with identifier of type SecondViewController")
return
}
vc.setObjectID(idToTransfer: whiteRussian)
present(vc, animated:true, completion: nil)
}
@IBAction func back(){
//Code is in Extension of UIViewController
moveBack()
}
func sort(resourceInMissions:[ResourceInMission]) -> [ResourceInMission] {
var arrayOfArrays = [[ResourceInMission](), [ResourceInMission](), [ResourceInMission](), [ResourceInMission](), [ResourceInMission](), [ResourceInMission]()]
// At first take the availability to sort.
// It produces availibility lists
for element in resourceInMissions {
// gets the index of the avail. from availibilities array
// for every avail a new list is made in arraysOfArray
if let string = element.getAvailability(){
if let av = availibilitys.index(of: string){
arrayOfArrays[av].append(element)
}
}
}
// Now iterate through each list and sort for the resourceType
// Idea is: get rsIM from one of the arrays above and put it in a type array for each element
// after finishing the avail array merge all type arrays for avail list sorted for types
var arraySorted:[ResourceInMission] = [ResourceInMission]()
for array in arrayOfArrays {
// lists have to be initialized for each loop
// otherwise the lists would be merged
var type1:[ResourceInMission] = [ResourceInMission]()
var type2:[ResourceInMission] = [ResourceInMission]()
var type3:[ResourceInMission] = [ResourceInMission]()
var type4:[ResourceInMission] = [ResourceInMission]()
var type5:[ResourceInMission] = [ResourceInMission]()
var type6:[ResourceInMission] = [ResourceInMission]()
var type7:[ResourceInMission] = [ResourceInMission]()
var type8:[ResourceInMission] = [ResourceInMission]()
for element in array {
if let id = element.getResourceID(){
if let resource = Resource().getByIdFromDB(id: id){
if let typeID = resource.getResourceTypeID(){
switch typeID {
case 1:
type1.append(element)
break
case 2:
type2.append(element)
break
case 3:
type3.append(element)
break
case 4:
type4.append(element)
break
case 5:
type5.append(element)
break
case 6:
type6.append(element)
break
case 7:
type7.append(element)
break
case 8:
type8.append(element)
break
default:
break
}
}
}
}
}
arraySorted = arraySorted + type1 + type2 + type3 + type4 + type5 + type6 + type7 + type8
}
return arraySorted
}
func setView(){
var count = 0
resourceInMissions = [ResourceInMission]()
resourceInMissions = try! ResourceInMission().getOverviewList()
count = resourceInMissions.count
resourceInMissions = sort(resourceInMissions: resourceInMissions)
Caipirinha = [String]()
Avails = [CAGradientLayer]()
Caipirinha.removeAll()
for index in 0 ..< resourceInMissions.count {
Caipirinha.append(resourceInMissions[index].toString())
let gradient: CAGradientLayer = CAGradientLayer()
if let av = resourceInMissions[index].getAvailability(){
switch av {
case availibilitys[0]:
//blue
let blue = [hexStringToUIColor(hex: "#E5EEFF"), hexStringToUIColor(hex: "#93B7FF"), hexStringToUIColor(hex: "#4F8EFF")]
gradient.colors = blue.map { $0.cgColor }
Avails.append(gradient)
break
case availibilitys[1]:
//red
let red = [hexStringToUIColor(hex: "#FFE5E5"), hexStringToUIColor(hex: "#FF8E8B"), hexStringToUIColor(hex: "#FF4F4F")]
gradient.colors = red.map { $0.cgColor }
Avails.append(gradient)
break
case availibilitys[2]:
//rose
let rose = [hexStringToUIColor(hex: "#FFFFFF"), hexStringToUIColor(hex: "#FDEADA"), hexStringToUIColor(hex: "#FAC090")]
gradient.colors = rose.map { $0.cgColor }
Avails.append(gradient)
break
case availibilitys[3]:
//yellow
let yellow = [hexStringToUIColor(hex: "#F5FFE6"), hexStringToUIColor(hex: "#F0FB85"), hexStringToUIColor(hex: "#FBF622")]
gradient.colors = yellow.map { $0.cgColor }
Avails.append(gradient)
break
case availibilitys[4]:
//green
let green = [hexStringToUIColor(hex: "#F5FFE6"), hexStringToUIColor(hex: "#C8FB85"), hexStringToUIColor(hex: "#BCFB5F")]
gradient.colors = green.map { $0.cgColor }
Avails.append(gradient)
break
case availibilitys[5]:
//grey
let gray = [hexStringToUIColor(hex: "#F2F2F2"), hexStringToUIColor(hex: "#E9E9E9"), hexStringToUIColor(hex: "D9D9D9")]
gradient.colors = gray.map { $0.cgColor }
Avails.append(gradient)
break
default:
break
}
}
}
self.tableView.reloadData()
}
}
答案 0 :(得分：1)
你的做法似乎对我不利。
你需要做下面的事情 1）创建一个名为GradientBackgroundView的UIView子类，并在此视图的绘制上绘制一个渐变 2）在你的故事板上，将uitableviewcell添加到你的tableview并添加GradientBackgroundView作为单元格的背景
希望这会对你有所帮助
答案 1 :(得分：0)
渐变看似随机的原因是细胞重复使用。
cell.textLabel?.layer.insertSublayer(gradient, at: 0)
每次显示一个单元格时都会调用此行，因此它第一次运行但是当您的单元格被重用时，新的渐变只会添加到旧的渐变之后。
您可以在添加新渐变图层之前删除旧渐变图层，也可以使用可以更新的渐变图层创建UITableViewCell子类。