Question

很难弄清楚如何遍历我的消息数据库，这样我就可以找到一个与用户电话号码相匹配的密钥......这种方法崩溃了以及我试过的所有其他方法也失败了。我真的可以使用帮助谢谢。

 func retrieveMessages(){
    let messagesDB = Database.database().reference().child("iMessenger/Messages")

    messagesDB.observe(.childAdded, with: {(snapshot) in
    let snapshotValue = snapshot.value as! Dictionary<String, String>

    //This conditional is suppose to filter out messages that aren't to or from the user
    if snapshotValue["sender"]! == userPhoneNumber || snapshotValue["receiver"]! == userPhoneNumber{

    let text = snapshotValue["messageBody"]!
    let sender = snapshotValue["sender"]!

    let message = Message()
    message.messageBody = text
    message.sender = sender

    self.messageArr.append(message)
    self.configureTableView()

    self.messagesTableView.reloadData()
    self.scrollToLastRow()}}

)}

Answer 1

您不应该尽可能在代码中使用!，如果值为nil，则必然会崩溃，我认为您需要将值向下转换为String比较电话号码，因此您可以按如下方式修改您的代码:(使用可选的绑定和向下转换）

if let snapshotValue = snapshot.value as? [String: Any], let senderNumber = snapshotValue["sender"] as? String,let receiverNumber = snapshotValue["receiver"] as? String  {

        //now you should compare these values as follows...
        if senderNumber == userPhoneNumber || receiverNumber == userPhoneNumber {
             //do your stuff...

        }

}

迭代firebase的子节点以查找与用户phoneNumber匹配的键

1 个答案: