xcode 在 UI Picker View Swift 中重新加载组件
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Reload Component in UI Picker View Swift
提问by mitch94
I am unable to reload the second component in my UIPickerViewthat is based on the first component. I tried using the reloadAllComponentsbut it either does not work or crashes. What I am trying to work on is place car makes on the left and models of their cars on the right. So when the car make changes, it would simultaneously change the right component model.
我无法重新加载UIPickerView基于第一个组件的第二个组件。我尝试使用 ，reloadAllComponents但它要么不起作用，要么崩溃。我正在努力的工作是将汽车制造商放在左侧，将他们的汽车模型放在右侧。因此，当汽车进行更改时，它会同时更改正确的组件模型。
class RegistrationPage: UIViewController,UIPickerViewDataSource, UIPickerViewDelegate {
@IBOutlet weak var usernameTextField: UITextField!
@IBOutlet weak var passwordTextField: UITextField!
@IBOutlet weak var passwordReTypeTextField: UITextField!
@IBOutlet weak var makePicker: UIPickerView!
@IBOutlet weak var modelPicker: UIPickerView!
@IBOutlet weak var licenseTagTextField: UITextField!
var picker1Options = []
var picker2Options = []
@IBAction func SubmitButton(sender: AnyObject) {
}
override func viewDidLoad() {
super.viewDidLoad()
makePicker = UIPickerView()
modelPicker = UIPickerView()
let makeAndModel = CarMakeModel();
picker1Options = makeAndModel.makeValues()
let firstValue = picker1Options.objectAtIndex(0)
picker2Options = makeAndModel.modelValues(firstValue as! String)
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 2
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if (component == 0) {
return picker1Options.count
} else {
return picker2Options.count
}
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
if component == 0 {
return "\(picker1Options[row])"
} else {
let makeAndModel = CarMakeModel();
let currentValue = picker1Options.objectAtIndex(row)
var picker2ptions = makeAndModel.modelValues(currentValue as! String)
return "\(picker2ptions[row])"
}
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let makeAndModel = CarMakeModel();
let currentValue = picker1Options.objectAtIndex(row)
var picker2ptions = makeAndModel.modelValues(currentValue as! String)
pickerView.reloadAllComponents()
}
}
Thanks!
谢谢！
采纳答案by vacawama
Here is a version that works. I created my own CarMakeModelclass to test it. You were overthinking the titleForRowfunction which was your primary problem. Also, in didSelectRowyou need to update the class property picker2Optionsand not a local variable. I changed other things. I'd recommend you compare my version to yours line by line to see the differences.
这是一个有效的版本。我创建了自己的CarMakeModel类来测试它。你过度思考了titleForRow你的主要问题的功能。此外，didSelectRow您需要更新类属性picker2Options而不是局部变量。我改变了其他的东西。我建议您逐行比较我的版本和您的版本以查看差异。
Also, there is only 1 pickerView needed, and it should be connected to the one in your Storyboard. You shouldn't be instantiating your own pickerViews.
此外，只需要 1 个 pickerView，它应该连接到您的 Storyboard 中的那个。你不应该实例化你自己的pickerViews。
class CarMakeModel {
func makeValues() -> [String] {
return ["Toyota", "Honda"]
}
func modelValues(make: String) -> [String] {
if make == "Toyota" {
return ["Camry", "Sienna", "Highlander"]
} else {
return ["Accord", "Civic", "Pilot"]
}
}
}
class RegistrationPage: UIViewController,UIPickerViewDataSource, UIPickerViewDelegate {
@IBOutlet weak var usernameTextField: UITextField!
@IBOutlet weak var passwordTextField: UITextField!
@IBOutlet weak var passwordReTypeTextField: UITextField!
@IBOutlet weak var makePicker: UIPickerView!
@IBOutlet weak var modelPicker: UIPickerView!
@IBOutlet weak var licenseTagTextField: UITextField!
var picker1Options:[String] = []
var picker2Options:[String] = []
@IBAction func SubmitButton(sender: AnyObject) {
}
override func viewDidLoad() {
super.viewDidLoad()
//makePicker = UIPickerView()
//modelPicker = UIPickerView()
let makeAndModel = CarMakeModel();
picker1Options = makeAndModel.makeValues()
let firstValue = picker1Options[0]
picker2Options = makeAndModel.modelValues(firstValue)
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 2
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if (component == 0) {
return picker1Options.count
} else {
return picker2Options.count
}
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
if component == 0 {
return "\(picker1Options[row])"
} else {
return "\(picker2Options[row])"
}
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
if component == 0 {
let makeAndModel = CarMakeModel();
let currentValue = picker1Options[row]
picker2Options = makeAndModel.modelValues(currentValue)
pickerView.reloadAllComponents()
}
}
}
回答by masc
for the font size modification:
对于字体大小修改：
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
var pickerLabel = view as? UILabel;
if (pickerLabel == nil)
{
pickerLabel = UILabel()
pickerLabel?.font = UIFont(name: "Helvetica Neue", size: 10)
pickerLabel?.textAlignment = NSTextAlignment.center
}
if component == 0 {
pickerLabel?.text = picker1Options[row]
} else {
pickerLabel?.text = picker2Options[row]
}
return pickerLabel!;
}
