未在子视图中调用UIPickerView委托
未在子视图中调用UIPickerView委托
提问于 2018-06-03 06:11:05
我有一个使用UISegmentedControl在两个选项卡之间切换的简单iOS应用程序。
在ViewController.swift中：
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var segment: UISegmentedControl!
@IBOutlet weak var viewContainer: UIView!
var searchView: UIView!
var favView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
searchView = SearchViewController().view
favView = FavoriteViewController().view
viewContainer.addSubview(favView)
viewContainer.addSubview(searchView)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
@IBAction func segmentChange(_ sender: UISegmentedControl) {
switch sender.selectedSegmentIndex{
case 0:
viewContainer.bringSubview(toFront: searchView)
break
case 1:
viewContainer.bringSubview(toFront: favView)
break
default:
break
}
}
}在第一个选项卡中，我有一个UIPickerView作为文本字段的输入。
import UIKit
class SearchViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
@IBOutlet weak var keywordField: UITextField!
@IBOutlet weak var categoryField: UITextField!
@IBOutlet weak var distanceField: UITextField!
@IBOutlet weak var locationField: UITextField!
var cgpicker = UIPickerView()
let categories = ["Default", "Airport", "Amusement Park", "Aquarium", "Art Gallery", "Bakery", "Bar"]
override func viewDidLoad() {
super.viewDidLoad()
cgpicker.delegate = self
cgpicker.dataSource = self
categoryField.inputView = cgpicker
categoryField.text = categories[0]
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
print("picker working")
return categories.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return categories[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
categoryField.text = categories[row]
categoryField.resignFirstResponder()
}
}但是，当我单击文本字段时，PickerView不显示数据。实际上，委托和数据源并没有被调用，因为"print“从来没有被调用过。然而，相同的代码在一个简单的UIView应用程序中工作得很好。我找不到任何与此问题相关的解决方案。
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-06-03 06:40:40
问题出在ViewController类的viewDidLoad上。
您没有正确创建容器视图控制器。阻止选取器工作的主要问题是，当viewDidLoad完成时，您的SearchViewController没有对它的强引用，因此SearchViewController中的选取器变成了nil。
将ViewController viewDidLoad更新为如下所示：
override func viewDidLoad() {
super.viewDidLoad()
let searchVC = SearchViewController()
searchView = searchVC.view
addChildViewController(searchVC)
// Should set searchView frame or constraints
viewContainer.addSubview(searchView)
searchVC.didMove(toParentViewController: self)
let favVC = FavoriteViewController()
favView = favVC.view
addChildViewController(favVC)
// Should set favView frame or constraints
viewContainer.addSubview(favView)
favVC.didMove(toParentViewController: self)
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50661575
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