当我尝试从我的数据库中获取 isBusy 属性的值时遇到问题。 A 使用断点,它甚至不转到我为 isBusy 赋值的指令,它分配空字符串并转到其他条件。
if docChild == 0 {
let selectedDoctor = Doctors.doc1
var isBusy = String()
databaseHandle = reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.isBusy).observe(.childAdded, with: { (snapshot) in
isBusy = snapshot.value as! String
})
if isBusy == "false" {
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.isBusy).setValue("true")
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.firstname).setValue(firstNameLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.lastname).setValue(lastNameLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.pesel).setValue(peselLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.telephone).setValue(phoneLabel.text)
} else {
createAlert(title: "Przepraszamy - termin jest zajęty", message: "Proszę wybrać inny termin")
}
最佳答案
答案相当简单。 Firebase 数据库请求是异步的,因此在您到达 if isBusy == "false"
语句时,不会从数据库中获取值。相应地更改您的代码:
if docChild == 0 {
let selectedDoctor = Doctors.doc1
var isBusy = String()
databaseHandle = reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.isBusy).observe(.childAdded, with: { (snapshot) in
isBusy = snapshot.value as! String
if isBusy == "false" {
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.isBusy).setValue("true")
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.firstname).setValue(firstNameLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.lastname).setValue(lastNameLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.pesel).setValue(peselLabel.text)
reference.child(selectedDoctor).child(dateChild).child(timeChild).child(ReservationFields.telephone).setValue(phoneLabel.text)
} else {
createAlert(title: "Przepraszamy - termin jest zajęty", message: "Proszę wybrać inny termin")
}
})
如您所见,我只是将您的代码移入处理程序,因此它会在获取您的值后执行。
关于swift - 无法从 Firebase 获取值(value),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46516370/