不能下标类型' [AnyObject]的值?'索引类型' UInt32'

时间:2015-05-18 05:58:59

标签: ios swift casting swift-array

下面代码的目标是这样 - 从名为OnlineUsers的parse.com类中获取所有对象,然后在0results.count之间找到一个RANDOM编号,然后使用该对象为了某事。

问题是,当我尝试将对象放在位置results[randomNumber]时,我收到以下错误。如果我在下面尝试results[randomNumberCast],我会收到相同的错误。

我该如何解决这个问题?

func findRandomOnlineUser() {
    if PFUser.currentUser() != nil {
        var user1 = PFUser.currentUser()
        var user2 = PFUser()



        //find user2, i.e. some user who is online right now
        //Showing OnlineUsers only
        let onlineUsersQuery = PFQuery(className: "OnlineUsers")
        onlineUsersQuery.findObjectsInBackgroundWithBlock({ (results:[AnyObject]?, error:NSError?) -> Void in

            if results!.count > 0 {
                self.mLog.printToLog("launchChatwithRandomUser() -- There are more than zero objects in OnlineUsers")

                //help: http://stackoverflow.com/questions/26770730/apple-swift-placing-a-variable-inside-arc4random-uniform
                let randomNumber = arc4random_uniform(UInt32(results!.count))
                var randomNumberCast = Int(randomNumber)

                if let userObject = results[randomNumberCast] {
                    user2 = userObject["user"] as! PFUser
                } else {
                    //handle the case of 'self.objects' being 'nil'
                }

    } else {
        //TODO: Show a prompt that user is not logged in and then take user to Login Screen
    }


}

错误讯息:

Screenshot showing the error message

1 个答案:

答案 0 :(得分:6)

results似乎是一个可选数组:[AnyObject]?。 因此,如果要通过下标访问其中一个值,则必须首先解包该数组:

if let userObject: AnyObject = results?[randomNumberCast]