使用来自 Firebase 的数据在地图上显示注释图像时出现奇怪的行为。 SWIFT 4.1
Strange behaviour in showing annotations images on map using data coming from Firebase. SWIFT 4.1
奇怪的是，当我添加一个新的注释时，无论是点击还是用户位置，它都会显示正确选择的图标。当 MapVC 第一次加载时，从 Firebase 检索到的 posts 具有所有相同的图标，（最新的 posted 的图标名称。如果在 posting 一个新的第一，我将 mapViewVc 退出到 menuVC，然后重新进入 mapViewVC，然后每个图标再次显示相同的图标，现在是我之前 posted 的图标。
有几次图标是随机选择的两个不同图标。
我不明白为什么坐标是正确的但图像不是。
应用流程是：
我有一个 mapView vc，我可以在其中双击屏幕并通过按钮获取坐标或代码用户位置坐标，然后进入 chooseIconVc，我可以在其中选择所有可用的图标来进行注释。一旦我 select 一个，图标名称就会在 unwindHere() 的 mapViewVC 中传回，它将图标名称存储到一个变量中，并将坐标存储到另一个变量中。在 postAlertNotification 中，这些变量被 posted 到 Firebase。
在 displayAlerts() 中，来自 Firebase 的数据被存储到变量中以初始化注释并被添加到 mapView。
选择的图标：
@IBAction func unwindHere(sender:UIStoryboardSegue) { // data coming back
if let sourceViewController = sender.source as? IconsViewController {
alertNotificationType = sourceViewController.dataPassed
if tapCounter > 0 {
alertNotificationLatitude = String(describing: alertCoordinates.latitude)
alertNotificationLongitude = String(describing: alertCoordinates.longitude)
postAlertNotification() // post new notification to Firebase
} else {
alertCoordinates = self.trackingCoordinates
alertNotificationLatitude = String(describing: self.trackingCoordinates!.latitude)
alertNotificationLongitude = String(describing: self.trackingCoordinates!.longitude)
postAlertNotification() // post new notification to Firebase
}
}
}
比post:
func postAlertNotification() {
// to set next notification id as the position it will have in array ( because first position is 0 ) we use the array.count as value
let latitude = alertNotificationLatitude
let longitude = alertNotificationLongitude
let alertType = alertNotificationType
let post: [String:String] = [//"Date" : date as! String,
//"Time" : time as! String,
"Latitude" : latitude as! String,
"Longitude" : longitude as! String,
"Description" : alertType as! String]
var ref: DatabaseReference!
ref = Database.database().reference()
ref.child("Community").child("Alert Notifications").childByAutoId().setValue(post)
}
检索并显示：
func displayAlerts() {
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
self.alertIconToDisplay = data["Description"]!
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
self.userAlertAnnotation = UserAlert(type: self.alertIconToDisplay!, coordinate: recombinedCoordinate, firebaseKey: firebaseKey)
self.mapView.addAnnotation(self.userAlertAnnotation)
})
}
和
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
let annotationView = MKAnnotationView(annotation: userAlertAnnotation, reuseIdentifier: "") // CHANGE FOR NEW ANNOTATION : FULL DATA
//added if statement for displaying user location blue dot
if annotation is MKUserLocation{
return nil
} else {
annotationView.image = UIImage(named: alertIconToDisplay!) // choose the image to load
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
变量声明：
var alertIconToDisplay: String?
var userAlertAnnotation: UserAlert!
var alertNotificationType: String?
var alertNotificationLatitude: String?
var alertNotificationLongitude: String?
更新：
注释cLass:
import MapKit
class UserAlert: NSObject , MKAnnotation {
var type: String?
var firebaseKey: String?
var coordinate = CLLocationCoordinate2D()
var image: UIImage?
override init() {
}
init(type:String, coordinate:CLLocationCoordinate2D, firebaseKey: String) {
self.type = type
self.firebaseKey = firebaseKey
self.coordinate = coordinate
}
}
在了解问题所在后，我被解释为如何将 displayAlert() 更改为
func displayAlerts() { // rajish version
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
let type = data["Description"]!
let id = Int(data["Id"]!)
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
var userAlertAnnotation = UserAlert(type: type, coordinate: recombinedCoordinate, firebaseKey: firebaseKey, title: type,id: id!)
self.userAlertNotificationArray.append(userAlertAnnotation) // array of notifications coming from Firebase
print("user alert array after append from Firebase is : \(self.userAlertNotificationArray)")
self.alertNotificationArray.append(recombinedCoordinate) // array for checkig alerts on route
self.mapView.addAnnotation(userAlertAnnotation)
})
}
和 mapView 到：
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? { // 拉吉什版本
let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "")
if annotation is MKUserLocation{
return nil
} else {
print(annotation.coordinate)
annotationView.image = UIImage(named:(annotationView.annotation?.title)! ?? "")
// annotationView.canShowCallout = true
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
解决了。
奇怪的是，当我添加一个新的注释时，无论是点击还是用户位置，它都会显示正确选择的图标。当 MapVC 第一次加载时，从 Firebase 检索到的 posts 具有所有相同的图标，（最新的 posted 的图标名称。如果在 posting 一个新的第一，我将 mapViewVc 退出到 menuVC，然后重新进入 mapViewVC，然后每个图标再次显示相同的图标，现在是我之前 posted 的图标。 有几次图标是随机选择的两个不同图标。 我不明白为什么坐标是正确的但图像不是。
应用流程是： 我有一个 mapView vc，我可以在其中双击屏幕并通过按钮获取坐标或代码用户位置坐标，然后进入 chooseIconVc，我可以在其中选择所有可用的图标来进行注释。一旦我 select 一个，图标名称就会在 unwindHere() 的 mapViewVC 中传回，它将图标名称存储到一个变量中，并将坐标存储到另一个变量中。在 postAlertNotification 中，这些变量被 posted 到 Firebase。 在 displayAlerts() 中，来自 Firebase 的数据被存储到变量中以初始化注释并被添加到 mapView。
选择的图标：
@IBAction func unwindHere(sender:UIStoryboardSegue) { // data coming back
if let sourceViewController = sender.source as? IconsViewController {
alertNotificationType = sourceViewController.dataPassed
if tapCounter > 0 {
alertNotificationLatitude = String(describing: alertCoordinates.latitude)
alertNotificationLongitude = String(describing: alertCoordinates.longitude)
postAlertNotification() // post new notification to Firebase
} else {
alertCoordinates = self.trackingCoordinates
alertNotificationLatitude = String(describing: self.trackingCoordinates!.latitude)
alertNotificationLongitude = String(describing: self.trackingCoordinates!.longitude)
postAlertNotification() // post new notification to Firebase
}
}
}
比post:
func postAlertNotification() {
// to set next notification id as the position it will have in array ( because first position is 0 ) we use the array.count as value
let latitude = alertNotificationLatitude
let longitude = alertNotificationLongitude
let alertType = alertNotificationType
let post: [String:String] = [//"Date" : date as! String,
//"Time" : time as! String,
"Latitude" : latitude as! String,
"Longitude" : longitude as! String,
"Description" : alertType as! String]
var ref: DatabaseReference!
ref = Database.database().reference()
ref.child("Community").child("Alert Notifications").childByAutoId().setValue(post)
}
检索并显示：
func displayAlerts() {
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
self.alertIconToDisplay = data["Description"]!
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
self.userAlertAnnotation = UserAlert(type: self.alertIconToDisplay!, coordinate: recombinedCoordinate, firebaseKey: firebaseKey)
self.mapView.addAnnotation(self.userAlertAnnotation)
})
}
和
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
let annotationView = MKAnnotationView(annotation: userAlertAnnotation, reuseIdentifier: "") // CHANGE FOR NEW ANNOTATION : FULL DATA
//added if statement for displaying user location blue dot
if annotation is MKUserLocation{
return nil
} else {
annotationView.image = UIImage(named: alertIconToDisplay!) // choose the image to load
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
变量声明：
var alertIconToDisplay: String?
var userAlertAnnotation: UserAlert!
var alertNotificationType: String?
var alertNotificationLatitude: String?
var alertNotificationLongitude: String?
更新：
注释cLass:
import MapKit
class UserAlert: NSObject , MKAnnotation {
var type: String?
var firebaseKey: String?
var coordinate = CLLocationCoordinate2D()
var image: UIImage?
override init() {
}
init(type:String, coordinate:CLLocationCoordinate2D, firebaseKey: String) {
self.type = type
self.firebaseKey = firebaseKey
self.coordinate = coordinate
}
}
在了解问题所在后，我被解释为如何将 displayAlert() 更改为
func displayAlerts() { // rajish version
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
let type = data["Description"]!
let id = Int(data["Id"]!)
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
var userAlertAnnotation = UserAlert(type: type, coordinate: recombinedCoordinate, firebaseKey: firebaseKey, title: type,id: id!)
self.userAlertNotificationArray.append(userAlertAnnotation) // array of notifications coming from Firebase
print("user alert array after append from Firebase is : \(self.userAlertNotificationArray)")
self.alertNotificationArray.append(recombinedCoordinate) // array for checkig alerts on route
self.mapView.addAnnotation(userAlertAnnotation)
})
}
和 mapView 到：
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? { // 拉吉什版本
let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "")
if annotation is MKUserLocation{
return nil
} else {
print(annotation.coordinate)
annotationView.image = UIImage(named:(annotationView.annotation?.title)! ?? "")
// annotationView.canShowCallout = true
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
解决了。