[英]viewController does not conform to protocol UIPickerViewDataSource what is wrong with my code?
我已经浏览了许多问题和答案,但找不到我的应用程序不断失败的原因。 很抱歉给您带来不便,但是有人可以帮我吗? 我正在使用Swift 3。
import UIKit
import MapKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate, UIPickerViewDelegate, UIPickerViewDataSource {
//Distance
@IBOutlet weak var setDistance: UIPickerView!
var distance = ["1/2 Mile", "1 Mile", "2 Miles", "5 Miles"]
//Map
@IBOutlet weak var map: MKMapView!
let manager = CLLocationManager()
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{
let location = locations[0]
let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)
let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation, span)
map.setRegion(region, animated: true)
print(location.altitude)
print(location.speed)
self.map.showsUserLocation = true
}
override func viewDidLoad()
{
super.viewDidLoad()
//Distance Stuff
setDistance.delegate = self
setDistance.dataSource = self
}
func numberOfComponents(in: UIPickerView) -> Int {
return 1
}
func setDistance(_ setDistance: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return distance.count
}
func setDistance(_ setDistance: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String {
return distance[row]
}
//Map Stuff
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
您应该像下面那样实现委托。问题说,您正在包含UIPickerViewDataSource但未实现其数据源
import UIKit
import MapKit
import CoreLocation
class TestViewController: UIViewController, CLLocationManagerDelegate, UIPickerViewDelegate, UIPickerViewDataSource {
//Distance
@IBOutlet weak var setDistance: UIPickerView!
var distance = ["1/2 Mile", "1 Mile", "2 Miles", "5 Miles"]
//Map
@IBOutlet weak var map: MKMapView!
let manager = CLLocationManager()
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{
let location = locations[0]
let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)
let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation, span)
map.setRegion(region, animated: true)
print(location.altitude)
print(location.speed)
self.map.showsUserLocation = true
}
override func viewDidLoad()
{
super.viewDidLoad()
//Distance Stuff
setDistance.delegate = self
setDistance.dataSource = self
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
}
/* func numberOfComponents(in: UIPickerView) -> Int {
return 1
}
func setDistance(_ setDistance: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return distance.count
}
func setDistance(_ setDistance: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String {
return distance[row]
}
*/
func numberOfComponents(in: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return distance.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return distance[row]
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
由于Xcode无法实现或建议所需的功能,因此我发现最好的识别方法是使用文档和API参考。
您可以在协议上显示快速帮助(Option +单击),然后单击“协议参考”:
这将打开文档和API参考,其中向您详细介绍了必需的功能:
您还可以搜索所需的关键作品(CMD + F)并在搜索字段中键入所需的内容。
然后,您可以在您的课程中实现它们:
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return dataset.count
}
Xcode帮助您找到相关功能,例如,开始键入pickerview
,它将为您提供协议功能列表:
而已。
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