Question

此问题在此站点上已被回答过好几次了，我已经尝试了全部，但没有任何效果。我认为的区别是UITableView中有一个UIViewController。在viewDidLoad中加载数据时，我已经尝试过了，这里显示的是我一直显示的屏幕，直到所有操作完成并出现新视图。我也在viewDidAppear内尝试过，这里有一个空白表，显示最终视图之前。

我已经从该站点尝试了4种方法，我在开始加载之前调用了pauseApp(n)，并在完成加载后调用了restartApp(n)

    var spinner:UIActivityIndicatorView = UIActivityIndicatorView()
    var loadingView = UIView()
    var loadingLabel = UILabel()
    var indicator = UIActivityIndicatorView()
    @IBOutlet weak var tvTable: UITableView!

    func pauseApp() {
        tvTable.activityIndicatorView.startAnimating()
        tvTable.activityIndicatorView.bringSubviewToFront(aIV)
        UIApplication.shared.beginIgnoringInteractionEvents()
    }
    func pauseApp1() {
        spinner = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
        spinner.center = self.navBar.center
        spinner.hidesWhenStopped = true
        spinner.style = UIActivityIndicatorView.Style.gray
        self.navigationController?.view.addSubview(spinner)
        spinner.startAnimating()
        UIApplication.shared.beginIgnoringInteractionEvents()
    }
    func pauseApp2() {
        tvTable.activityIndicatorView.startAnimating()
        indicator.startAnimating()
        indicator.backgroundColor = UIColor.white
        UIApplication.shared.beginIgnoringInteractionEvents()
    }
    func pauseApp3() {
        setLoadingScreen()
        UIApplication.shared.beginIgnoringInteractionEvents()
    }
    func restartApp() {
    //        sleep(2)
        tvTable.activityIndicatorView.stopAnimating()
        UIApplication.shared.endIgnoringInteractionEvents()
    }
    func restartApp1() {
        spinner.stopAnimating()
        UIApplication.shared.endIgnoringInteractionEvents()
    }
    func restartApp2() {
    //        sleep(2)
        indicator.stopAnimating()
        indicator.hidesWhenStopped = true
        UIApplication.shared.endIgnoringInteractionEvents()
    }
    func restartApp3() {
    //       sleep(2)
        removeLoadingScreen()
        UIApplication.shared.endIgnoringInteractionEvents()
    }
    private func setLoadingScreen() {
        let width: CGFloat = 120
        let height: CGFloat = 30
        let x = (view.frame.width / 2) - (width / 2)
        let y = (view.frame.height / 2) - (height / 2) - 20
        loadingView.frame = CGRect(x: x, y: y, width: width, height: height)

        // Sets loading text
        loadingLabel.textColor = .gray
        loadingLabel.textAlignment = .center
        loadingLabel.text = "Loading..."
        loadingLabel.frame = CGRect(x: 0, y: 0, width: 140, height: 30)

        // Sets spinner
        spinner.style = .gray
        spinner.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
        spinner.startAnimating()

        // Adds text and spinner to the view
        loadingView.addSubview(spinner)
        loadingView.addSubview(loadingLabel)

        view.addSubview(loadingView)
        view.bringSubviewToFront(loadingView)

    }
    private func removeLoadingScreen() {
        spinner.stopAnimating()
        spinner.isHidden = true
        loadingLabel.isHidden = true
    }

    func activityIndicator()  {
        indicator = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
        indicator.style = UIActivityIndicatorView.Style.gray
        indicator.center = self.view.center
        self.view.addSubview(indicator)
    }
    fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"
    public var aIV: UIActivityIndicatorView = UIActivityIndicatorView()
    public extension UITableView {
        var activityIndicatorView: UIActivityIndicatorView {
            get {
                if let aIV = getAssociatedObject(&ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
                return aIV
                } else {
                    let aIV = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
                    aIV.style = .gray
                    aIV.color = .gray
                    aIV.backgroundColor = UIColor.black
                    aIV.center = center
                    aIV.hidesWhenStopped = true
                    addSubview(aIV)

                    setAssociatedObject(aIV, associativeKey: &ActivityIndicatorViewAssociativeKey, policy: .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
                   aIV.bringSubviewToFront(aIV)
                   return aIV
                }
            }

            set {
                addSubview(newValue)
                setAssociatedObject(newValue, associativeKey:&ActivityIndicatorViewAssociativeKey, policy: .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            }
        }
    }
    public extension NSObject {
        func setAssociatedObject(_ value: AnyObject?, associativeKey: UnsafeRawPointer, policy: objc_AssociationPolicy) {
            if let valueAsAnyObject = value {
                objc_setAssociatedObject(self, associativeKey, valueAsAnyObject, policy)
            }
        }

        func getAssociatedObject(_ associativeKey: UnsafeRawPointer) -> Any? {
            guard let valueAsType = objc_getAssociatedObject(self, associativeKey) else {
                return nil
            }
            return valueAsType
        }
    }

Answer 1

验证您的Interface Builder文件，尤其是定义组件的顺序。层次结构中较高的组件可能被其下方定义的那些组件隐藏。因此，您的表视图很有可能会隐藏您的活动视图。

您应该能够通过隐藏表格视图和其他可能位于顶部的其他视图来相当快地确认这一点。根据您的活动视图设置，您可能还需要执行application/x-www-form-urlencoded。请注意，由于UITableView实现了内置的scrollview，因此将活动视图作为子级添加到UITableView可能不是最好的方法。您最好将其定义为tableView的superview的子级。参考：

您对tvTable.activityIndicatorView.isHidden = false的尝试可以进行一些小的修改，但前提是您的视图控制器位于导航控制器内部。您还应该始终仅在将视图添加为子视图之后才定义任何关系。

从头开始一个全新的项目，这是如何通过代码显示活动指示器的方法：

pauseApp1

Answer 2

再次感谢您，解决方案是在TableView下面添加带有Storyboard的activityIndeicatorView 然后在viewDidAppear中有 @IBOutlet弱var mySpinner：UIActivityIndicatorView！

override func viewDidAppear(_ animated: Bool) {
    self.pauseApp()
   DispatchQueue.main.asyncAfter(deadline: .now()) {
    self.doScreen()
   }
}
func pauseApp() {
    showSpinner()
    UIApplication.shared.beginIgnoringInteractionEvents()

}

func restartApp() {
    mySpinner.stopAnimating()
    UIApplication.shared.endIgnoringInteractionEvents()
}
private func showSpinner() {
    mySpinner.startAnimating()
    mySpinner.isHidden = false
    mySpinner.hidesWhenStopped = true
}

pauseApp调用将微调器显示在屏幕上，doScreen完成所有工作，并在完成后调用restartApp。我的doScreen要做大量的工作去获取数据，良好的Internet连接大约需要2秒钟，但是当连接不良时会花费更长的时间。

我正在尝试获取UIActivityIndicatorView以在加载UITableView时显示

2 个答案:

我正在尝试获取UIActivityIndi​​catorView以在加载UITableView时显示

2 个答案:

我正在尝试获取UIActivityIndicatorView以在加载UITableView时显示