swift – 使用计时器定期更新NSTableCellView内的文本字段

我创建了一个计时器(带有中央显示器),每100毫秒我用setNeedsDisplay更新textView(或swift中的.needsDisplay = truE).

我在具有NSTextField的常规视图中工作的代码很好,但是一旦文本字段是NSTableCellView的一部分,它就无法工作.计时器触发,但不重绘该字段.

如果我从viewController中每100毫秒重新加载整个表,它也无法工作.在任何情况下重新加载整个表都不是一个好的解决方案,因为选择每100毫秒丢失一次并且用户不能再编辑(常规)单元格.

那么我应该如何每秒在整个tableview的几个单元格中重新加载一个特定的textField呢？

@IBDesignable class ProgressCellView : NSTableCellView
{
//MARK: properties
@IBInspectable var clock : Bool = false //should this type of cell show a clock? (is set to true in interface builder)

private lazy var formatter = TimeIntervalFormatter() //move to view controller?: 1 timer for the entire table => but then SELEction is lost
private var timer : dispatch_source_t!
private var isRunning : Bool = false

//MARK: init
override func awakeFromNib()
{
    self.timeIndex?.formatter = formatter
    if self.clock
    {
        self.timer = dispatch_source_create(DISPATCH_sourcE_TYPE_TIMER,dispatch_get_main_queue())
        dispatch_source_set_timer(timer,dispatch_time(DISPATCH_TIME_Now,0),100 * NSEC_PER_MSEC,50 * NSEC_PER_MSEC) //50 ms leeway,is good enough for the human eye
        dispatch_source_set_event_handler(timer) {
            self.timeIndex?.needsDisplay = true
            //self.needsDisplay = true
            //self.superview?.needsDisplay = true
        }
    }

}

//only run the clock when the view is visible
override func viewWillMoveToSuperview(newSuperview: NSView?)
{
    super.viewWillMoveToSuperview(newSuperview)
    if self.clock && !isRunning { dispatch_resume(self.timer); isRunning = true }
}

override func removeFromSuperview()
{
    super.removeFromSuperview()
    if self.clock && isRunning { dispatch_suspend(self.timer); isRunning = false  }
}

//MARK: properties
override var objectValue: AnyObject? {
    didSet {
        let entry = self.objectValue as! MyEntry
        self.progressBar?.doubleValue = entry.progress?.fractionCompleted ?? 0

        self.timeIndex?.objectValue = entry.dateStarted         
    }
}

//MARK: user interface
@IBOutlet var timeIndex     : NSTextField?
@IBOutlet var progressBar   : NSProgressInDicator?

}