【发布时间】：2019-12-01 10:57:02
【问题描述】：
我正在向我的应用程序添加一个自定义委托，但由于某种原因，它无法正常工作。 我的应用程序有一张地图，其中显示了不同公司类型的几个标记。还有一个按钮，一旦按下，就会带我到另一个视图控制器，用户可以在其中输入一些过滤器。然后用户按下“应用”，这会将过滤数据传递给地图视图控制器。 这里的问题是没有数据被传递。 作为参考，我遵循了https://medium.com/@jamesrochabrun/implementing-delegates-in-swift-step-by-step-d3211cbac3ef 的指导方针，它工作得很好。
这里是完整的项目代码https://github.com/afernandes0001/Custom-Delegate
我使用 Firebase，但下面的代码只显示了与委托相关的部分。
mapViewController - 你会注意到我在 prepareForSegue 中添加了一个打印。首次加载应用程序并单击“搜索”按钮时，它将 nav1 显示为 nil（这是预期的），但是，如果我单击搜索并应用（在 filterVC 中），则打印永远不会完成。
import UIKit
import MapKit
class MapViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate, FilterVCDelegate {
@IBOutlet weak var map: MKMapView!
override func viewDidLoad() {
super.viewDidLoad()
map.register(MyAnnotationView.self, forAnnotationViewWithReuseIdentifier: MKMapViewDefaultAnnotationViewReuseIdentifier)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "clinicDetailsSegue" {
let clinicsDetailsViewController = segue.destination as! ClinicsDetailsViewController
clinicsDetailsViewController.id = self.note.mapId
} else if segue.identifier == "searchSegue" {
print("segue call")
let nav1 = segue.destination as? UINavigationController
print("nav1 \(nav1)")
if let nav = segue.destination as? UINavigationController, let filterVC = nav.topViewController as? FilterViewController {
filterVC.delegate = self
}
}
}
func chosenData(clinicNameFilter: String, stateFilter: String, cityFilter: String, esp1Filter: String, esp2Filter: String) {
print("Received data \(clinicNameFilter), \(stateFilter), \(cityFilter), \(esp1Filter), \(esp2Filter)")
}
}
过滤视图控制器
import UIKit
protocol FilterVCDelegate: class {
func chosenData(clinicNameFilter: String, stateFilter: String, cityFilter: String, esp1Filter: String, esp2Filter: String)
}
class FilterViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
weak var delegate: FilterVCDelegate?
var selectedName = ""
var statesJSON = [Estado]()
var cities = [Cidade]()
var state : Estate? // Selected State identifier
var city : City? // Selected City identifier
var selectedState = "" // Used to retrieve info from Firebase
var selectedCity = "" // Used to retrieve info from Firebase
var specialtiesJSON = [Specialty]()
var specialties2 = [Specialty2]()
var specialty1 : Specialty? // Selected Specialty1 identifier
var specialty2 : Specialty2? // Selected Specialty2 identifier
var selectedSpecialty1 = ""
var selectedSpecialty2 = ""
@IBOutlet weak var clinicName: UITextField!
@IBOutlet weak var statePicker: UIPickerView!
@IBOutlet weak var esp1Picker: UIPickerView!
@IBOutlet weak var esp2Picker: UIPickerView!
override func viewDidLoad() {
readJsonStates()
readJsonSpecialties()
super.viewDidLoad()
clinicName.text = ""
}
@IBAction func applyFilter(_ sender: Any) {
if clinicName.text == nil {
clinicName.text = ""
}
if selectedState != "" {
if selectedCity != "" {
if selectedSpecialty1 != ""{
if selectedSpecialty2 != "" {
delegate?.chosenData(clinicNameFilter: clinicName.text!, stateFilter: selectedState, cityFilter: selectedCity, esp1Filter: selectedSpecialty1, esp2Filter: selectedSpecialty2)
let viewControllers: [UIViewController] = self.navigationController!.viewControllers as [UIViewController]
self.navigationController?.popToViewController(viewControllers[viewControllers.count - 2], animated: true)
} else {
print("Fill in all filter data")
}
} else {
print("Fill in all filter data")
}
} else {
print("Fill in all filter data")
}
} else {
print("Fill in all filter data")
}
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
esp1Picker.reloadComponent(0)
esp2Picker.reloadComponent(0)
statePicker.reloadAllComponents()
if pickerView == statePicker {
if component == 0 {
self.state = self.statesJSON[row]
self.coties = self.statesJSON[row].cities
statePicker.reloadComponent(1)
statePicker.selectRow(0, inComponent: 1, animated: true)
} else {
self.city = self.cities[row]
statePicker.reloadAllComponents()
}
} else if pickerView == esp1Picker {
self.specialty1 = self.specialtiesJSON[row]
self.specialties2 = self.specialtiesJSON[row].specialty2
esp1Picker.reloadComponent(0)
esp2Picker.reloadComponent(0)
esp2Picker.selectRow(0, inComponent: 0, animated: true)
} else if pickerView == esp2Picker {
self.specialty2 = self.specialties2[row]
esp1Picker.reloadComponent(0)
esp2Picker.reloadComponent(0)
}
let indexSelectedState = statePicker.selectedRow(inComponent: 0)
let indexSelectedCity = statePicker.selectedRow(inComponent: 1)
let indexSelectedEsp1 = esp1Picker.selectedRow(inComponent: 0)
let indexSelectedEsp2 = esp2Picker.selectedRow(inComponent: 0)
if indexSelectedState >= 0 {
if indexSelectedCity >= 0 {
selectedState = estadosJSON[indexSelectedState].name
selectedCity = cidades[indexSelectedCity].name
}
}
if indexSelectedEsp1 >= 0 {
if indexSelectedEsp2 >= 0 {
selectedSpecialty1 = specialtiesJSON[indexSelectedEsp1].name
selectedSpecialty2 = specialtiesJSON[indexSelectedEsp1].specialty2[indexSelectedEsp2].name
}
}
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
if pickerView == statePicker {
return 2
} else if pickerView == esp1Picker {
return 1
} else if pickerView == esp2Picker {
return 1
}
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if pickerView == statePicker {
if component == 0 {
return statesJSON.count
} else {
return cities.count
}
} else if pickerView == esp1Picker {
return self.specialtiesJSON.count
} else if pickerView == esp2Picker {
return specialties2.count
}
return 1
}
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
var rowTitle = ""
let pickerLabel = UILabel()
pickerLabel.textColor = UIColor.black
if pickerView == statePicker {
if component == 0 {
rowTitle = statesJSON[row].name
} else {
rowTitle = cities[row].name
}
} else if pickerView == esp1Picker {
rowTitle = specialtiesJSON[row].name
} else if pickerView == esp2Picker {
rowTitle = specialties2[row].name
}
pickerLabel.text = rowTitle
pickerLabel.font = UIFont(name: fontName, size: 16.0)
pickerLabel.textAlignment = .center
return pickerLabel
}
func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
if pickerView == statePicker {
if component == 0 {
return 50
} else {
return 300
}
}
return 300
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
view.endEditing(true)
}
func readJsonStates() {
let url = Bundle.main.url(forResource: "StatesAndCities", withExtension: "json")!
do {
let data = try Data(contentsOf: url)
let jsonResult = try JSONDecoder().decode(RootState.self, from: data)
//handles the array of countries on your json file.
self.statesJSON = jsonResult.state
self.cities = self.statesJSON.first!.cities
} catch {
}
}
func readJsonSpecialties() {
let url = Bundle.main.url(forResource: "Specialties", withExtension: "json")!
do {
let data = try Data(contentsOf: url)
let jsonResult = try JSONDecoder().decode(RootEsp.self, from: data)
//handles the array of specialties on your json file.
self.specialtiesJSON = jsonResult.specialty
self.specialties2 = self.specialtiesJSON.first!.specialty2
} catch {
}
}
}
知道为什么当我单击 ApplyFilter 时，MapViewController 中的委托没有更新吗？
谢谢
【问题讨论】：