如何在用户触摸已选择的行时隐藏 UIPIckerView

Question

我的代码中有多个 UIPickerView，假设用户无意中打开了 PickerView，但希望保持选中同一行，就像我在用户触摸已选中的行时所做的那样，选择器隐藏？

我试过这个：UIPicker detect tap / touch on currently selected row，但我无法让它工作。

--- 编辑 ---

我会尽量说得更具体一些。我是编程和 Swift 语言的初学者。

这是我的ViewController.swift

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

@IBOutlet weak var colorLabel: UILabel!
@IBOutlet weak var sizeLabel: UILabel!

@IBOutlet weak var colorButton: UIButton!
@IBOutlet weak var sizeButton: UIButton!

@IBOutlet weak var resultButton: UIButton!

@IBOutlet weak var colorPickerView: UIPickerView! = UIPickerView()
@IBOutlet weak var sizePickerView: UIPickerView! = UIPickerView()

var colorPickerData = ["Blue", "Red"]
var sizePickerData = ["Small", "Big"]

var descri = String()
var resultadoImagem = UIImage()

override func viewDidLoad() {
    super.viewDidLoad()


    colorPickerView.isHidden = true
    sizePickerView.isHidden = true


    self.colorPickerView.delegate = self
    self.colorPickerView.dataSource = self

    self.sizePickerView.delegate = self
    self.sizePickerView.dataSource = self


    colorLabel.text = colorPickerData[0]
    sizeLabel.text = sizePickerData[0]
}

override func didReceiveMemoryWarning() {

    super.didReceiveMemoryWarning()

}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if pickerView.tag == 1 {
        return colorPickerData.count
    } else if pickerView.tag == 2 {
        return sizePickerData.count
    }
    return 0
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if pickerView.tag == 1 {
        return "\(colorPickerData[row])"
    } else if pickerView.tag == 2 {
        return "\(sizePickerData[row])"
    }
    return ""
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if pickerView.tag == 1 {
        colorLabel.text = colorPickerData[row]
        colorPickerView.isHidden = true
    } else if pickerView.tag == 2 {
        sizeLabel.text = sizePickerData[row]
        sizePickerView.isHidden = true
    }
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    colorPickerView.isHidden = true
    sizePickerView.isHidden = true
}

@IBAction func colorButton(_ sender: Any) {
    colorPickerView.isHidden = !colorPickerView.isHidden
}

@IBAction func sizeButton(_ sender: Any) {
    sizePickerView.isHidden = !sizePickerView.isHidden
}

@IBAction func resultButton(_ sender: Any) {
    if (colorLabel.text == "Blue")
        && (sizeLabel.text == "Big") { resultadoImagem = UIImage(named: "blue-big.png")!; descri = "BLUE"}
    else if (colorLabel.text == "Blue")
        && (sizeLabel.text == "Small") { resultadoImagem = UIImage(named: "blue-small.png)!; descri = "BLUE"}
    else if (colorLabel.text == "Red")
        && (sizeLabel.text == "Big") { resultadoImagem = UIImage(named: "red-big.png")!; descri = "RED"}
    else if (colorLabel.text == "Red")
        && (sizeLabel.text == "Small") { resultadoImagem = UIImage(named: "red-small.png")!; descri = "RED"}

    self.performSegue(withIdentifier: "resultSegue", sender: nil)
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "resultSegue" {
        let DestViewController : SecondViewController = segue.destination as! SecondViewController

    DestViewController.descText = descri
    DestViewController.resultPhoto = resultadoImagem
    }
}

}

这段代码效果很好，当我点击 "Result" 按钮时，它会转到 SecondViewController 并显示照片和描述。

我的困难是，colorPickerView 打开时数据 "Blue" 被选中，就像 sizerPickerView 默认打开时数据 "Small" 一样。当用户触摸已选择的数据时，我希望 pickerView close/hide。

Answer 1

遵守 class 到 UIGestureRecognizerDelegate 协议

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UIGestureRecognizerDelegate { 
    // ... 
}

将 UITapGestureRecognizer 添加到您的 colorPickerView

let tap = UITapGestureRecognizer(target: self, action: #selector(self.tapAction(_:)))
tap.cancelsTouchesInView = false
tap.delegate = self
colorPickerView.addGestureRecognizer(tap)

实施UIGestureRecognizerDelegate方法

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}

最终实施tapAction

func tapAction(_ tapRecognizer:UITapGestureRecognizer) {
    if tapRecognizer.state == .ended {
        let rowHeight : CGFloat  = colorPickerView.rowSize(forComponent: 0).height
        let selectedRowFrame: CGRect = colorPickerView.bounds.insetBy(dx: 0.0, dy: (colorPickerView.frame.height - rowHeight) / 2.0)
        let userTappedOnSelectedRow = selectedRowFrame.contains(tapRecognizer.location(in: colorPickerView))
        if (userTappedOnSelectedRow){
            let selectedRow = colorPickerView.selectedRow(inComponent: 0)
            //do whatever you want here
        }
    }
}

使用 sizerPickerView 重复步骤 2 和 4 以扩展功能。

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