如何从另一个视图控制器调用UIPickerView子类中的方法？
问题描述：
我有一个UIPickerView，我分类，这很好。然而，我有一个方法，我需要调用UIPicker从它被查看的UIViewController中“重置”。但是，它永远不会燃烧。如何从另一个视图控制器调用？如何从另一个视图控制器调用UIPickerView子类中的方法？
import Foundation
import UIKit
class ScoreClockPicker: UIPickerView {
//PickerView
let timerMinutesArray = Array(00...20)
let timerSecondsArray = Array(00...59)
let periodArray = ["1st", "2nd", "3rd", "OT", "SO"]
//Picker return values
var numberOfRowsInComponentReturnValue = 0
var titleForRowReturnValue = ""
var widthForComponentReturnValue = ""
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.delegate = self
self.dataSource = self
}
func resetPicker() {
print("resetPicker")
self.selectRow(0, inComponent: 0, animated: true)
self.selectRow(0, inComponent: 1, animated: true)
self.selectRow(0, inComponent: 3, animated: true)
}
}
extension ScoreClockPicker: UIPickerViewDataSource {
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if component == 0 {
numberOfRowsInComponentReturnValue = periodArray.count
} else if component == 1 {
numberOfRowsInComponentReturnValue = timerMinutesArray.count
} else if component == 2 {
numberOfRowsInComponentReturnValue = 1
} else if component == 3 {
numberOfRowsInComponentReturnValue = timerSecondsArray.count
}
return numberOfRowsInComponentReturnValue
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 4
}
func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
var componentWidth = 0
if component == 0 {
componentWidth = 140
} else if component == 1 {
componentWidth = 40
} else if component == 2 {
componentWidth = 30
} else if component == 3 {
componentWidth = 40
}
return CGFloat(componentWidth)
}
}
extension ScoreClockPicker: UIPickerViewDelegate {
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
print("didSelectRow")
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if component == 0 {
titleForRowReturnValue = periodArray[row]
} else if component == 1 {
titleForRowReturnValue = String(describing: timerMinutesArray[row])
} else if component == 2 {
titleForRowReturnValue = ":"
} else if component == 3 {
titleForRowReturnValue = String(format: "%02d",timerSecondsArray[row])
}
return titleForRowReturnValue
}
}
编辑：
下不从的viewController调用ScoreClockPicker工作：
import UIKit
class ScoreClockViewController: UIViewController {
@IBOutlet weak var resetButton: UIButton!
@IBOutlet weak var okButton: UIButton!
var picker: ScoreClockPicker?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
//Hide the Navigation Bar
self.navigationController?.setNavigationBarHidden(false, animated: true)
}
//@IBOutlet
@IBAction func reset(_ sender: Any) {
print("reset")
picker?.resetPicker() //Call the ScoreClockPicker
// picker?.selectRow(0, inComponent: 0, animated: true)
// picker?.selectRow(0, inComponent: 1, animated: true)
// picker?.selectRow(0, inComponent: 3, animated: true)
}
@IBAction func ok(_ sender: Any) {
}
}
答
从你的代码中没有初始化的picker对象，你要使用在按钮操作中。所以在使用之前只需简单地初始化picker即可。
如果您做的ScoreClockPicker出口则
@IBOutlet var picker: ScoreClockPicker!
也可以在viewDidLoad
self.picker = ScoreClockPicker()
+0
@PaulS。欢迎队友:) –
初始化
picker添加要在其中创建ScoreClockPicker'的'对象的代码。意味着添加你的ViewController的代码。 –@NiravD，请参阅上面的编辑。我试过了，它不起作用。 –
如果你已经初始化了这个'picker'对象，那么我们也会显示它的代码，并且复位是否是按钮操作？ –