如何更新NSProgressIndicator？

Question

我有問題NSProgress。問題是NSProgressIndicator在此過程中沒有更新，並且在過程結束時只顯示一小部分已完成部分。 localizedDescription也僅在流程結束時顯示，但已完成100％。

所以，我有一類具有使用一種方法findRepeatsWithProgressReportingNSProgress

class TestProgress: NSObject, ProgressReporting 
{ 
    let progress: Progress 

    override init() 
    { 
     progress = Progress() 
     super.init() 
    } 

    func findRepeatsWithProgressReporting(stringToSearch: String, minimalLength: Int, maximalLength: Int) -> [String] 
    { 
     var arrayOfRepeats = [String]() 

     progress.totalUnitCount = Int64((minimalLength...maximalLength).count) 

     for i in minimalLength...maximalLength 
     { 
      let arrayOfStrings = stringToSearch.chopString(stringOut: stringToSearch, length: i) 
      let arrayOfUniqueStrings = Array(Set(arrayOfStrings)) 

      for each in arrayOfUniqueStrings 
      { 
       let arrayOfNSRanges = stringToSearch.searchForNSRangesOfStringInString(stringOut: stringToSearch, stringIn: each) 

       var positions = String() 

       if arrayOfNSRanges.count > 1 
       { 
        for each1 in arrayOfNSRanges 
        { 
         let repeatStart = String(each1.location + 1) 
         let repeatEnd = String(each1.location + each1.length) 
         positions += "(" + repeatStart + "-" + repeatEnd + ")" 
        } 
        let stringToShow = each + " " + positions 
        arrayOfRepeats.append(stringToShow) 
       } 
      } 
      progress.completedUnitCount += 1 
     } 
     return arrayOfRepeats 
    } 

} 

然後，在myVewContrloler我有parentProgress repeatsProgress具有totalUnitCount: 10和已添加的方法findRepeatsWithProgressReporting的任務作爲childProgress使用repeatsProgress.becomeCurrent(withPendingUnitCount: 10)的parentProgress repeatsProgress 。

private var progressObservationContext = 0 

class myVewContrloler: NSViewController 
{ 
    ... 

    var testProgress = TestProgress() 
    var repeatsProgress = Progress() 

    @IBOutlet weak var repeatsSearchProgressBar: NSProgressIndicator! 
    @IBOutlet weak var repeatsPercentText: NSTextField! 

    @IBOutlet weak var minimalLength: NSTextField! 
    @IBOutlet weak var maximalLength: NSTextField! 
    @IBOutlet var foundRepeats: NSTextView! 

    @IBAction func actionFindRepeats(_ sender: AnyObject) 
    { 
     repeatsProgress = Progress(totalUnitCount: 10) 

     let options : NSKeyValueObservingOptions = [.new, .old, .initial, .prior] 
     repeatsProgress.addObserver(self, forKeyPath: "fractionCompleted", options: options, context: &progressObservationContext) 
     repeatsProgress.addObserver(self, forKeyPath: "localizedDescription", options: options, context: &progressObservationContext) 

     var arrayOfRepeats = [String]() 

     repeatsProgress.becomeCurrent(withPendingUnitCount: 10) 
     arrayOfRepeats = testProgress.findRepeatsWithProgressReporting(stringToSearch: stringToSearch, minimalLength: minimalLength.integerValue, maximalLength: maximalLength.integerValue) 

     ... 

     repeatsProgress.removeObserver(self, forKeyPath: "fractionCompleted") 
     repeatsProgress.removeObserver(self, forKeyPath: "localizedDescription") 

     repeatsProgress.resignCurrent() 
    } 
} 

最後一部分是志願：

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) 
{ 
     guard context == &progressObservationContext else { 
     super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context) 
     return 
    } 

    if keyPath == "fractionCompleted" 
    { 
     OperationQueue.main.addOperation{ 
       let progress = object as! Progress 
       self.repeatsSearchProgressBar.doubleValue = progress.fractionCompleted 
       self.repeatsPercentText.stringValue = progress.localizedDescription 
     } 
    } 
} 

我已經加入

print("Observed Something") 

的

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) 
{ ... 

，我看到裏面是兩次印刷"Observed Something"立即在開始之後和最後6次之間，沒有打印之間（因爲它預計將用於更新過程）。可能是什麼原因？

Answer 1

這看起來像是一個併發問題。由於func actionFindRepeats(_ sender: AnyObject)正在主線程中運行，因此它與UI更新一致，這會直接影響NSProgressIndicator。

見這個答案的最後一個例子爲更多細節是：

• https://stackoverflow.com/a/35810608/4370893

你可以嘗試添加您actionFindRepeats的所有內容功能成塊，看看它的工作原理：

DispatchQueue.global().async { 
    // qos' default value is ´DispatchQoS.QoSClass.default` 
} 

參考該塊：

• https://stackoverflow.com/a/37806522/4370893