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展开一个可选值我不断收到以下错误:致命错误:意外发现零,而使用cloudkit
fatal error: unexpectedly found nil while unwrapping an Optional value
,我想我只是不明白为什么。有人能帮我找到我的错误吗?它是可变的结果是可选的吗?
错误一直指向viewDidLoad()
中的一行,我评论说在哪里。谢谢。
//
// ViewController.swift
// Physics Help!
//
// Created by Sam Hanson on 2/8/15.
// Copyright (c) 2015 Sam Hanson. All rights reserved.
//
import UIKit
import CloudKit
class ViewController: UIViewController {
//VARIABLES********************************************************
@IBOutlet var c1Answer: UILabel!
@IBOutlet var questions: UILabel!
var resultsOfDB : String = ""
var indexes : [Int] = []
var counter : Int = 0
var newStr : String = ""
//*****************************************************************
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.questions.text = String(getNewQbutton()) //error points to here*********
}
//load the answers, grab them from the cloud base
@IBAction func loadAnswers() {
let container = CKContainer.defaultContainer()
var publicDB = container.publicCloudDatabase
let myQuery = CKQuery(recordType: "QuestionsTable", predicate: NSPredicate(value: true))
publicDB.performQuery(myQuery, inZoneWithID: nil){
results, error in
if error != nil {
println(error)
}
else
{
dispatch_async(dispatch_get_main_queue(), {() -> Void in
self.c1Answer.text = results.description
println(results.description)
})
}
}
}
@IBAction func getNewQbutton() {
let container = CKContainer.defaultContainer()
var publicDB = container.publicCloudDatabase
let myQuery = CKQuery(recordType: "QuestionsTable", predicate: NSPredicate(value: true))
publicDB.performQuery(myQuery, inZoneWithID: nil){
results, error in
if error != nil {
println(error)
}
else
{
dispatch_async(dispatch_get_main_queue(), {() -> Void in
self.resultsOfDB = results.description
//for each character in resultsOfDB
for character in self.resultsOfDB{
if(character == "\""){
self.indexes.append(self.counter)
}
self.counter++
}
self.newStr = self.resultsOfDB.substringWithRange(Range<String.Index>(start: advance(self.resultsOfDB.startIndex, self.indexes[0] + 1), end: advance(self.resultsOfDB.endIndex, -(self.counter - self.indexes[1]))))
self.questions.text = self.newStr
})
}
self.counter = 0
}
}
我检查了问题的连接,它只连接到一个UILabel。难道这可能是某种方式,这个函数会把一个无价值的东西放到questions.text里面导致错误? – CS8800 2015-02-23 19:52:59
请看我的udpate – 2015-02-23 20:04:06
谢谢,我想我明白了!谢谢youuuu! – CS8800 2015-02-23 20:07:24