UIPickerView 在滚动时跳过数组中的值
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【中文标题】UIPickerView 在滚动时跳过数组中的值【英文标题】：UIPickerView jumps over values in array while scroll it 【发布时间】：2018-06-09 18:10:21 【问题描述】：我遇到了 UIPickerView 的问题。我有一个应用程序，其中 UITextField 的 inputView 设置为 UIPickerView。当它出现时，一切正常。该行的标题是正确的，但是当我向下滚动到下一个元素时，它以某种方式传递了数组的一些值并停在错误的值上。最后，标题不等于它的实际值。
这是我的代码：
class ViewController: UIViewController
...
// MARK: - Race outlet
@IBOutlet weak var raceTextField: UITextField!
// MARK: - "Purchased" column outlets
@IBOutlet weak var purchasedStrTextField: UITextField!
@IBOutlet weak var purchasedDexTextField: UITextField!
@IBOutlet weak var purchasedConTextField: UITextField!
@IBOutlet weak var purchasedIntTextField: UITextField!
@IBOutlet weak var purchasedWisTextField: UITextField!
@IBOutlet weak var purchasedChaTextField: UITextField!
...
// MARK: - "Actual" column outlets
@IBOutlet weak var actualStrLabel: UILabel!
@IBOutlet weak var actualDexLabel: UILabel!
@IBOutlet weak var actualConLabel: UILabel!
@IBOutlet weak var actualIntLabel: UILabel!
@IBOutlet weak var actualWisLabel: UILabel!
@IBOutlet weak var actualChaLabel: UILabel!
...
// MARK: - Constants
let pickerView = UIPickerView()
// MARK: - Variables
var raceArray = [Race]()
var selectedTextField: Int!
// MARK: - Lifecicle
override func viewDidLoad()
super.viewDidLoad()
configurePickerView()
congigureTextFields()
createRaces()
...
...
// MARK: - Methods
func createRaces()
let human = Race(str: 0, dex: 0, con: 0, int: 0, wis: 0, cha: 0,
raceDesrciption: "Human (add +2 to any one ability)", raceMod: true)
let elf = Race(str: 0, dex: 2, con: -2, int: 2, wis: 0, cha: 0,
raceDesrciption: "Elf", raceMod: false)
let halfElf = Race(str: 0, dex: 0, con: 0, int: 0, wis: 0, cha: 0,
raceDesrciption: "Half-Elf (add +2 to any one ability)", raceMod: true)
let dwarf = Race(str: 0, dex: 0, con: 2, int: 0, wis: 2, cha: -2,
raceDesrciption: "Dwarf", raceMod: false)
let hafling = Race(str: -2, dex: 2, con: 0, int: 0, wis: 0, cha: 2,
raceDesrciption: "Hafling", raceMod: false)
let gnome = Race(str: -2, dex: 0, con: 2, int: 0, wis: 0, cha: 2,
raceDesrciption: "Gnome", raceMod: false)
let halfOrc = Race(str: 0, dex: 0, con: 0, int: 0, wis: 0, cha: 0,
raceDesrciption: "Half-Orc (add +2 to any one ability)", raceMod: true)
let other = Race(str: 0, dex: 0, con: 0, int: 0, wis: 0, cha: 0,
raceDesrciption: "Other", raceMod: true)
raceArray.append(human)
raceArray.append(elf)
raceArray.append(halfElf)
raceArray.append(dwarf)
raceArray.append(hafling)
raceArray.append(gnome)
raceArray.append(halfOrc)
raceArray.append(other)
/// Set parameters for specific race
func setDefaultPoints(_ selectedRace: String)
for item in raceArray
if selectedRace == item.raceDesrciption
raceModeStrTextField.text = "\(item.str!)"
raceModeDexTextField.text = "\(item.dex!)"
raceModeConTextField.text = "\(item.con!)"
raceModeIntTextField.text = "\(item.int!)"
raceModeWisTextField.text = "\(item.wis!)"
raceModeChaTextField.text = "\(item.cha!)"
setActualPointsForRace(item)
switchRaceModTextTield(item.editableRaceMod)
/// Update "Actual points" labels
func setActualPointsForRace(_ race: Race)
actualStrLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.str)"
strLabel.text = actualStrLabel.text
actualDexLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.dex)"
dexLabel.text = actualDexLabel.text
actualConLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.con)"
conLabel.text = actualConLabel.text
actualIntLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.int)"
intLabel.text = actualIntLabel.text
actualWisLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.wis)"
wisLabel.text = actualWisLabel.text
actualChaLabel.text = "\(Int(lowPoweredValueLabel.text!)! - race.cha)"
chaLabel.text = actualChaLabel.text
func setTotalPointsWith(_ points: Int)
let currentValue = Int(totalPointValueLabel.text!)!
totalPointValueLabel.text = "\(currentValue + points)"
这是我的UIPickerView 代码：
extension ViewController: UIPickerViewDelegate, UIPickerViewDataSource
func configurePickerView()
pickerView.delegate = self
pickerView.dataSource = self
pickerView.showsSelectionIndicator = true
func numberOfComponents(in pickerView: UIPickerView) -> Int
return 1
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
if selectedTextField == 1
print(raceArray.count)
return raceArray.count
else
print(purchaseValues.count)
return purchaseValues.count
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
switch selectedTextField
case 1:
raceTextField.text = raceArray[row].raceDesrciption
return raceArray[row].raceDesrciption
case 2:
purchasedStrTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
case 3:
purchasedDexTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
case 4:
purchasedConTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
case 5:
purchasedIntTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
case 6:
purchasedWisTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
case 7:
purchasedChaTextField.text = "\(purchaseValues[row].0)"
return "\(purchaseValues[row].0)"
default:
print("no value")
return nil
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
switch selectedTextField
case 1:
setDefaultPoints(raceArray[row].raceDesrciption)
case 2:
actualStrLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
case 3:
actualDexLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
case 4:
actualConLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
case 5:
actualIntLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
case 6:
actualWisLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
case 7:
actualChaLabel.text = "\(purchaseValues[row].0)"
setTotalPointsWith(purchaseValues[row].1)
default:
print("no value")
TextFields 配置：
extension ViewController: UITextFieldDelegate
func congigureTextFields()
raceTextField.inputView = pickerView
purchasedStrTextField.inputView = pickerView
purchasedDexTextField.inputView = pickerView
purchasedConTextField.inputView = pickerView
purchasedIntTextField.inputView = pickerView
purchasedWisTextField.inputView = pickerView
purchasedChaTextField.inputView = pickerView
raceTextField.delegate = self
purchasedStrTextField.delegate = self
purchasedDexTextField.delegate = self
purchasedConTextField.delegate = self
purchasedIntTextField.delegate = self
purchasedWisTextField.delegate = self
purchasedChaTextField.delegate = self
raceModeStrTextField.delegate = self
raceModeDexTextField.delegate = self
raceModeConTextField.delegate = self
raceModeIntTextField.delegate = self
raceModeWisTextField.delegate = self
raceModeChaTextField.delegate = self
func textFieldDidBeginEditing(_ textField: UITextField)
selectedTextField = textField.tag
pickerView.reloadAllComponents()
还有purchaseValues数组：
let purchaseValues = [
(7, -4),
(8, -2),
(9, -1),
(10, 0),
(11, 1),
(12, 2),
(13, 3),
(14, 5),
(15, 7),
(16, 10),
(17, 13),
(18, 17)
]
【问题讨论】：
打印语句的输出无关紧要。您不能对调用titleForRow 的顺序做出任何假设。您对选择器视图的实际问题是什么？根据您的代码，选择器应该以正确的顺序显示元组中的键。
@rmaddy 我很抱歉控制台中的混乱！问题是选择器的 numberOfRowsInComponent 返回数组的计数 28 次。我不知道为什么会这样。
调用多少次或以什么顺序都无关紧要。你的选择器是否真的显示了正确的数据？不用担心您的打印报表。
我认为不是。因为那时我必须在滚动UIPickerView 时将键的值分配给特定的UILabel。最后它在UIPicker 的行中显示了正确的标题，但为UILabel 分配了不正确的值。
您能否发布一组适合的代码。您现在有两个 titleForRow 方法，新的一个引用您之前没有提到的变量。这是无法调试的。
【参考方案1】：
正如@rmaddy 所说：“...titleForRow 的唯一目的是告诉选取器视图为所请求的行使用什么标题。” - 这是我犯错的地方。非常感谢！
【讨论】：
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