如果在文本字段触摸时委托数据为空，如何使 UIPickerView 不显示？

Question

如果用户在文本字段内触摸以开始编辑时 statusArray 为空，我不想显示 UIPickerView。我的要求是在输入 3 个字符后，我将进行 Web 服务调用。在主应用程序中，我收到了所有响应数据并显示在 UIPickerView 上。请建议我如何隐藏 UIPickerView 直到我收到服务器的响应。

这是我的示例代码（不包括 Web 服务调用）

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {


@IBOutlet weak var statusText: UITextField!

let statusArray  = [String]()
let picker = UIPickerView()

override func viewDidLoad() {
    super.viewDidLoad()

    picker.dataSource = self
    picker.delegate = self


    //binding textfield to picker view
    statusText.inputView = picker


}

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

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return statusArray.count
}


func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return statusArray[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    statusText.text = statusArray[row]
}

}

//来自网络服务的回调方法

DispatchQueue.main.sync {

for location in locationDetails.ianaLocationInfoArray
{


    let optionToView = location.ianaCode! + " - " + location.facilityName!
    self.locationArray.append(optionToView)
    self.picker.reloadAllComponents()





}
     applicationUtils.hideActivityIndicator(uiView: self.view)
}

Answer 1

也许你可以在 viewDidLoad 中这样制作：

if statusArray.count == 0 {
    picker.isHidden = true
}

Answer 2

在网络服务响应中：

if statusArray.count > 0{
  statusText.inputView = picker
}

Answer 3

首先在viewDidLoad方法中检查statusArray.count。

if statusArray.count == 0 {
    picker.isHidden = true
}

插入3个字符后向服务器请求获取数据。（按照你说的。）
并检查以下条件 ...

if statusArray.count > 0 {
    picker.isHidden = false
}

Answer 4

// set inputView later if condition meets
// txtLocationCode.inputView = picker

// In callback method from web service, change the input type
// to picker instead of keyboard if condition meets

if(self.locationArray.count>0) {

    // below 3 lines are to set inputview as picker and to see picker immediately
    self.txtLocationCode.inputView = self.picker
    self.txtLocationCode.resignFirstResponder()
    self.txtLocationCode.becomeFirstResponder()
}

Answer 5

只需在任意位置编写并调用 pickerview 扩展中的函数，即可将 picker 视图重置为第一行

extension UIPickerView {

    func reloadPicker(_ animated : Bool){
        print("\n\n Extension Is Calling \n\n")
        self.reloadAllComponents()
        self.selectRow(0, inComponent: 0, animated: animated)
    }
}

如果在文本字段触摸时委托数据为空，如何使 UIPickerView 不显示？

How to make UIPickerView not to display if delegate data is empty on textfield touch?

uipickerview

uitextfield

ios

swift3