Question

我正在尝试将我正在从Firebase数据库中读取的信息保存到变量中。这是我阅读我的信息的方式：

dbHandle = dbReference?.child("users").child(userEmail!).child("state").observe(.value, with: { (snapshot) in
        if let userState = (snapshot.value as? String){
            var taxRate = self.stateAbbreviations[userState]!
            print(taxRate)
        }

    })

我现在的问题是如何制作userState＆amp; taxRate在此次通话之外可见？

我已经尝试在调用之外声明userState，在其中初始化它，并再次在外面引用它但它不起作用。例如：

var userState:String? = ""
dbHandle = dbReference?.child("users").child(userEmail!).child("state").observe(.value, with: { (snapshot) in
        let userState = (snapshot.value as? String)
        var taxRate = self.stateAbbreviations[userState]!
        print(taxRate)
    })
print(userState)

但它只打印出＆＃34;＆＃34;

有什么建议吗？

Answer 1

您正在将var userState初始化为空字符串，并且您在完成之外的打印检索其默认值，在您的firebase完成中，您正在使用let userState =初始化另一个userState变量

如果您想在呼叫之外使用userState和taxRate，您可以这样做，例如：

// Create your variables 
var userState: String = “”

//Create a func with completion handler
func getUserStateAndTaxRate(completion:((String,String) -> Void)?) {
    dbHandle = dbReference?.child("users").child(userEmail!).child("state").observe(.value, with: { (snapshot) in
        let userState = (snapshot.value as? String)
        var taxRate = self.stateAbbreviations[userState]!
        print(taxRate)
        completion?(userState, taxRate)
    })
}

//Then call it
getUserStateAndTaxRate { (userState, taxRate) in 
    // userState and taxRate are now available 
    self.userState = userState 
    self.taxRate = taxRate 
}

将Firebase快照分配给变量

1 个答案: