满足条件后如何快速停止活动指示器? [英] How to stop the activity indicator in swift after a condition is met?

问题描述

我已将 UIActivityIndi​​catorView 声明为模型扩展中的计算属性.我有一个方法 configureCell ，我试图在其中使用活动指示器作为 imageView 的子视图.在这里，我可以将指标置于特定条件下，但以后无法对其进行任何更改.例如，我无法停止活动指示器，无法更改颜色，甚至无法隐藏它.

I have declared a UIActivityIndicatorView as a computed property in extension of my model. I have a method configureCell where I'm trying to use activity indicator as a subview of an imageView. Here I'm able to position the indicator on certain condition but am not able to do any changes on it later. E.g I am not able to stop the activity indicator, not able to change the color, not able to even hide it.

extension TranscationModel: UITableViewDataSource, UITableViewDelegate
{

 var activityIN: UIActivityIndicatorView {
    var act = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
    act.color = UIColor.redColor()
    act.hidden = false
    act.startAnimating()
    return act
}

func configureTransactionCell(cell : TransactionCell?, indexPath: NSIndexPath) {
    if transaction.tid == "Something" {
        activityIN.color = UIColor.greenColor() //Even this doesn't work
        activityIN.center = cell.imgTransactionBill.center
        cell.imgTransactionBill.addSubview(activityIN)
        let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(10 * Double(NSEC_PER_SEC)))
        dispatch_after(delayTime, dispatch_get_main_queue()) {
             activityIN.stopAnimating() //Not working
             activityIN.hidden = true   //Not working
        }
    }
}

推荐答案

您将 activityIN 定义为计算变量.任何时候当你调用它时，你都会得到一个全新的实例.在 UIActivityIndi​​catorView 的便利初始值设定项中查看 activityIN var.如果您只需要 10 秒钟的活动，请像这样编辑您的 func:

You defined activityIN as computed variable. Any time when you call it, you get completely new instance. Look at activityIN var as at convenience initializer of UIActivityIndicatorView. If you only need activity for ten seconds, edit your func like this:

func configureTransactionCell(cell : TransactionCell?, indexPath: NSIndexPath) {
    if transaction.tid == "Something" {
        let weakActivityIndicator = activityIN
        weakActivityIndicator.color = UIColor.greenColor()
        weakActivityIndicator.center = cell.imgTransactionBill.center
        cell.imgTransactionBill.addSubview(weakActivityIndicator)
        let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(10 * Double(NSEC_PER_SEC)))
        dispatch_after(delayTime, dispatch_get_main_queue()) {
             weakActivityIndicator.stopAnimating()
             weakActivityIndicator.hidden = true
        }
    }
}

但通常你需要保持对从这个初始化器获得的实例的引用.在 TransactionCell 类中定义 UIActivityIndi​​catorView 存储属性.

But usually you need to keep reference to instance that you get from this initializer. Define UIActivityIndicatorView stored property in your TransactionCell class.

假设 TransactionCell 类有声明

var cellActivityIndicator: UIActivityIndicatorView!

然后你可以像这样编辑你的函数

then you can edit your func like this

func configureTransactionCell(cell : TransactionCell?, indexPath: NSIndexPath) {
    if transaction.tid == "Something" {
        cell.cellActivityIndicator = activityIN
        cell.cellActivityIndicator.color = UIColor.greenColor()
        cell.cellActivityIndicator.center = cell.imgTransactionBill.center
        cell.imgTransactionBill.addSubview(cell.cellActivityIndicator)
        let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(10 * Double(NSEC_PER_SEC)))
        dispatch_after(delayTime, dispatch_get_main_queue()) {
             cell.cellActivityIndicator.stopAnimating()
             cell.cellActivityIndicator.hidden = true
        }
    }
}

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