我正在尝试使用来自另一个 JSON 调用的数据重新填充我的 UITableView。
但是我当前的设置似乎不起作用，虽然在 SO 上有很多相同的问题，但我已经尝试过我能找到的答案。
我将我的 API 数据保存在 CoreData 实体对象中。我正在用我的 CoreData 实体填充我的 UITableView。
在我当前的设置中，我有 3 个不同的 API 调用，它们具有不同的数据量，当然还有不同的值。我需要能够在这 3 个数据集之间切换，这就是我现在想要完成的。 (到目前为止没有进展)。
我有一个名为“loadSuggestions”的函数，我认为这是我的错误所在。
首先我检查互联网连接。
我设置了 managedObjectContext
我检查我需要调用哪些 API(这是在调用函数之前确定的，我检查它是否按预期工作)
我从它尝试调用的实体中删除所有当前数据。 (我还尝试从
UITableView加载的最后数据中删除数据。这并没有改变任何东西)。我还检查了这是否有效。删除数据后，我检查它打印出一个空数组，我还尝试记录它删除的对象以确保。然后我获取新数据，将其保存到临时变量中。然后保存到我的核心数据中。
然后我进行第二次 API 调用(取决于第一个 API 的变量)，获取该数据并以相同方式保存。
我将对象追加到数组中，
UITableView从中填充它的单元格。 (我检查过它也能正确打印出来)最后我重新加载了 tableView。 (不改变一件事)
函数如下:
func loadSuggestions() {
println("----- Loading Data -----")
// Check for an internet connection.
if Reachability.isConnectedToNetwork() == false {
println("ERROR: -> No Internet Connection <-")
} else {
// Set the managedContext again.
managedContext = appDelegate.managedObjectContext!
// Check what API to get the data from
if Formula == 0 {
formulaEntity = "TrialFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/entry_weekly.json")
} else if Formula == 1 {
formulaEntity = "ProFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/entry_weekly.json")
} else if Formula == 2 {
formulaEntity = "PremiumFormulaStock"
formulaAPI = NSURL(string: "http://api.com/json/proff_weekly.json")
println("Setting Entity: \(formulaEntity)")
} else if Formula == 3 {
formulaEntity = "PlatinumFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/fund_weekly.json")
}
// Delete all the current objects in the dataset
let fetchRequest = NSFetchRequest(entityName: formulaEntity)
let a = managedContext.executeFetchRequest(fetchRequest, error: nil) as! [NSManagedObject]
for mo in a {
managedContext.deleteObject(mo)
}
// Removing them from the array
stocks.removeAll(keepCapacity: false)
// Saving the now empty context.
managedContext.save(nil)
// Set up a fetch request for the API data
let entity = NSEntityDescription.entityForName(formulaEntity, inManagedObjectContext:managedContext)
var request = NSURLRequest(URL: formulaAPI!)
var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
var formula = JSON(data: data!)
// Loop through the api data.
for (index: String, actionable: JSON) in formula["actionable"] {
// Save the data into temporary variables
stockName = actionable["name"].stringValue
ticker = actionable["ticker"].stringValue
action = actionable["action"].stringValue
suggestedPrice = actionable["suggested_price"].floatValue
weight = actionable["percentage_weight"].floatValue
// Set up CoreData for inserting a new object.
let stock = NSManagedObject(entity: entity!,insertIntoManagedObjectContext:managedContext)
// Save the temporary variables into coreData
stock.setValue(stockName, forKey: "name")
stock.setValue(ticker, forKey: "ticker")
stock.setValue(action, forKey: "action")
stock.setValue(suggestedPrice, forKey: "suggestedPrice")
stock.setValue(weight, forKey: "weight")
// Get ready for second API call.
var quoteAPI = NSURL(string: "http://dev.markitondemand.com/Api/v2/Quote/json?symbol=\(ticker)")
// Second API fetch.
var quoteRequest = NSURLRequest(URL: quoteAPI!)
var quoteData = NSURLConnection.sendSynchronousRequest(quoteRequest, returningResponse: nil, error: nil)
if quoteData != nil {
// Save the data from second API call to temporary variables
var quote = JSON(data: quoteData!)
betterStockName = quote["Name"].stringValue
lastPrice = quote["LastPrice"].floatValue
// The second API call doesn't always find something, so checking if it exists is important.
if betterStockName != "" {
stock.setValue(betterStockName, forKey: "name")
}
// This can simply be set, because it will be 0 if not found.
stock.setValue(lastPrice, forKey: "lastPrice")
} else {
println("ERROR ----------------- NO DATA for \(ticker) --------------")
}
// Error handling
var error: NSError?
if !managedContext.save(&error) {
println("Could not save \(error), \(error?.userInfo)")
}
// Append the object to the array. Which fills the UITableView
stocks.append(stock)
}
// Reload the tableview with the new data.
self.tableView.reloadData()
}
}
目前，当我推送到这个 viewController 时，这个函数在 viewDidAppear 中被调用，如下所示:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(true)
tableView.allowsSelection = true
if isFirstTime {
loadSuggestions()
isFirstTime = false
}
}
它正确地填充了 tableView，一切似乎都按计划进行。
但是，如果我打开滑出式菜单并调用一个函数来加载不同的数据，则什么也没有发生，这是一个示例函数:
func platinumFormulaTapGesture() {
// Menu related actions
selectView(platinumFormulaView)
selectedMenuItem = 2
// Setting the data to load
Formula = 3
// Sets the viewController. (this will mostly be the same ViewController)
menuTabBarController.selectedIndex = 0
// Set the new title
navigationController?.navigationBar.topItem!.title = "PLATINUM FORMULA"
// And here I call the loadSuggestions function again. (this does run)
SuggestionsViewController().loadSuggestions()
}
这是 2 个相关的 tableView 函数:
行数:
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return stocks.count
}
还有 cellForRowAtIndexPath，(这是我用 CoreData 设置我的单元格的地方)
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("com.mySuggestionsCell", forIndexPath: indexPath) as! mySuggestionsCell
let formulaStock = stocks[indexPath.row]
cell.stockNameLabel.text = formulaStock.valueForKey("name") as! String!
cell.tickerLabel.text = formulaStock.valueForKey("ticker") as! String!
action = formulaStock.valueForKey("action") as! String!
suggestedPrice = formulaStock.valueForKey("suggestedPrice") as! Float
let suggestedPriceString = "Suggested Price\n$\(suggestedPrice.roundTo(2))" as NSString
var suggestedAttributedString = NSMutableAttributedString(string: suggestedPriceString as String)
suggestedAttributedString.addAttributes(GrayLatoRegularAttribute, range: suggestedPriceString.rangeOfString("Suggested Price\n"))
suggestedAttributedString.addAttributes(BlueHalisRBoldAttribute, range: suggestedPriceString.rangeOfString("$\(suggestedPrice.roundTo(2))"))
cell.suggestedPriceLabel.attributedText = suggestedAttributedString
if action == "SELL" {
cell.suggestionContainer.backgroundColor = UIColor.formulaGreenColor()
}
if let lastPrice = formulaStock.valueForKey("lastPrice") as? Float {
var lastPriceString = "Last Price\n$\(lastPrice.roundTo(2))" as NSString
var lastAttributedString = NSMutableAttributedString(string: lastPriceString as String)
lastAttributedString.addAttributes(GrayLatoRegularAttribute, range: lastPriceString.rangeOfString("Last Price\n"))
percentDifference = ((lastPrice/suggestedPrice)*100.00)-100
if percentDifference > 0 && action == "BUY" {
lastAttributedString.addAttributes(RedHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference <= 0 && percentDifference > -100 && action == "BUY" {
lastAttributedString.addAttributes(GreenHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference <= 0 && percentDifference > -100 && action == "SELL" {
lastAttributedString.addAttributes(RedHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference == -100 {
lastPriceString = "Last Price\nN/A" as NSString
lastAttributedString = NSMutableAttributedString(string: lastPriceString as String)
lastAttributedString.addAttributes(GrayLatoRegularAttribute, range: lastPriceString.rangeOfString("Last Price\n"))
lastAttributedString.addAttributes(BlackHalisRBoldAttribute, range: lastPriceString.rangeOfString("N/A"))
}
cell.lastPriceLabel.attributedText = lastAttributedString
} else {
println("lastPrice nil")
}
weight = formulaStock.valueForKey("weight") as! Float
cell.circleChart.percentFill = weight
let circleChartString = "\(weight.roundTo(2))%\nWEIGHT" as NSString
var circleChartAttributedString = NSMutableAttributedString(string: circleChartString as String)
circleChartAttributedString.addAttributes(BlueMediumHalisRBoldAttribute, range: circleChartString.rangeOfString("\(weight.roundTo(2))%\n"))
circleChartAttributedString.addAttributes(BlackSmallHalisRBoldAttribute, range: circleChartString.rangeOfString("WEIGHT"))
cell.circleChartLabel.attributedText = circleChartAttributedString
cell.selectionStyle = UITableViewCellSelectionStyle.None
return cell
}
我将我的 appDelegate 定义为我类的第一件事:
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
var managedContext = NSManagedObjectContext()
我认为这就是可能导致错误的所有代码。同样，我认为最有可能的原因是 loadSuggestions 函数。
为了强制更新 tableView，我还尝试在 self.view 和 tableView 上调用 setNeedsDisplay 和 setNeedsLayout ，两者似乎都没有做任何事情。
任何关于找出为什么这个 tableView 拒绝更新的建议都会有很大的帮助!
对于代码墙，我深表歉意，但我无法找到问题的确切根源。
最佳答案
platinumFormulaTapGesture 函数中的这一行不正确，
SuggestionsViewController().loadSuggestions()
这会创建一个新的 SuggestionsViewController 实例，它不是您在屏幕上看到的实例。你需要得到一个指向你拥有的那个的指针。你如何做到这一点取决于你的 Controller 层次结构，你没有充分解释。
关于ios - 使用新数据快速更新 UITableView，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29660543/