问题
I am currently trying to access data from a child snapshot in Swift. Here is my code that I have (which worked before the Swift 3/Firebase update):
if let achievements = snapshot1.childSnapshotForPath("Achievements").children.allObjects as? [FIRDataSnapshot] {
if achievements.count != 0 {
if let val = achievements[0].value!["somevalue"] as? Int {
self.dict["somevalue"] = val
}
}
So what I am trying to do here, is to create a variable of a child snapshot (achievements), and access child snapshot data from it. The achievements[0] will simply return the very first value. However, this doesn't seem to work. How should I approach this?
I am currently doing this inside a snapshot already (of 'observeType:.ChildAdded')
My Firebase DB looks like this:
Achievements{
randomId1 {
somevalue : somevalue
}
randomId2 {
somevalue2 : somevalue2
}
}
Updated code:
func loadData() {
ref.child("Players").observe(FIRDataEventType.childAdded) { (snapshot:FIRDataSnapshot) in
if let value = snapshot.value as? [String:AnyObject], let username = value["Username"] as? String {
}
if let value = snapshot.value as? [String:AnyObject], let ranking = value["Rank"] as? String {
}
if let childSnapshot = snapshot.childSnapshot(forPath: "Achievements").children.allObjects as? [FIRDataSnapshot] {
if childSnapshot.count != 0 {
if let achievement1 = childSnapshot[0].value!["Rookie"] as? String {
print(achievement1)
}
}
}
}
}
JSON Tree:
Players {
PlayerID {
Username
Rank
Achievements {
Rookie: yes
}
}
回答1:
Try :-
if let childSnapshot = snapshot.childSnapshot(forPath: "Achievements") as? FIRDataSnapshot{
if let achievementDictionary = childSnapshot.value as? [String:AnyObject] , achievementDictionary.count > 0{
if let achieveMedal = achievementDictionary["Rookie"] as? String {
print(achieveMedal)
}
}
}
来源：https://stackoverflow.com/questions/39623524/swift-firebase-access-child-snapshot-data