如何在tableView加载时显示活动指示器？

时间：2015-04-28 07:22:18

标签： ios uitableview swift uiactivityindicatorview

当我在我的标签之间切换时，它会加载几秒钟，我想知道我的数据正在加载。为此，我决定添加一个活动指标。

我写了一个小功能：

func showActivityIndicator() {
    dispatch_async(dispatch_get_main_queue()) {
        self.spinner = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)
        self.spinner.frame = CGRect(x: 0.0, y: 0.0, width: 80.0, height: 80.0)
        self.spinner.center = CGPoint(x:self.loadingView.bounds.size.width / 2, y:self.loadingView.bounds.size.height / 2)

        self.loadingView.addSubview(self.spinner)
        self.view.addSubview(self.loadingView)
        self.spinner.startAnimating()
    }
}

将显示我的指标。当我从infoController中点击按钮时尝试使用它：

@IBAction func goToMainFromInfo(sender: AnyObject) {
        self.showActivityIndicator()
        self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
        self.hideActivityIndicator()
    }
}

我在segue执行之前显示它并隐藏在之后。它对我没有帮助。当我尝试使用同步时：

@IBAction func goToMainFromInfo(sender: AnyObject) {
    dispatch_async(dispatch_get_main_queue()) {
        self.showActivityIndicator()
        self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
        self.hideActivityIndicator()
    }
}

但它也没有帮助。当我按Tab键时，不透明度变为0.5，我在加载时等待。但我没有看到我的活动指标。

有什么问题？

12 个答案:

答案 0 :(得分：50)

试试这个：

var indicator = UIActivityIndicatorView()

func activityIndicator() {
    indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
    indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    indicator.center = self.view.center
    self.view.addSubview(indicator)    
}

你想开始动画的地方

indicator.startAnimating()
indicator.backgroundColor = UIColor.whiteColor()

停止：

indicator.stopAnimating()
indicator.hidesWhenStopped = true

注意：避免同时调用start和stop。只是给出一些条件。

答案 1 :(得分：18)

Swift 3.0

// UIView扩展

fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"
public extension UIView {
   var activityIndicatorView: UIActivityIndicatorView {
        get {
            if let activityIndicatorView = getAssociatedObject(&ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
                return activityIndicatorView
            } else {
                let activityIndicatorView = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
                activityIndicatorView.activityIndicatorViewStyle = .gray
                activityIndicatorView.color = .gray
                activityIndicatorView.center = center
                activityIndicatorView.hidesWhenStopped = true
                addSubview(activityIndicatorView)

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

        set {
            addSubview(newValue)
            setAssociatedObject(newValue, associativeKey:&ActivityIndicatorViewAssociativeKey, policy: .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
}

// NSObject扩展

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
    }
}

开始动画

tableView.activityIndicatorView.startAnimating()

停止动画

tableView.activityIndicatorView.stopAnimating()

您可以在Magic

中找到更多代码

答案 2 :(得分：14)

Swift 2+ 

    class ViewController: UITableViewController {
        weak var activityIndicatorView: UIActivityIndicatorView!

        override func viewDidLoad() {
            super.viewDidLoad()
            let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
            tableView.backgroundView = activityIndicatorView
            self.activityIndicatorView = activityIndicatorView
            activityIndicatorView.startAnimating()

        }
        ...
    }

答案 3 :(得分：3)

我使用两种扩展方法将Index mismatch: 168586039d6b675e5ba51706ea759f8ee701a538 != 45485a0f950096c26425196ab7e7fd54c042d4cc rereading 284599fe3bd0720c7c516191d67031d855d6a3c6 Svndiff data contains backward-sliding source view: Svndiff has backwards-sliding source views at C:/Program Files/Git/mingw64/share/perl5/Git/SVN/Ra.pm line 312. 添加为表视图的UIActivityIndicatorView。

backgroundView

您可以像这样显示/隐藏它。

extension UITableView {
    func showActivityIndicator() {
        DispatchQueue.main.async {
            let activityView = UIActivityIndicatorView(style: .medium)
            self.backgroundView = activityView
            activityView.startAnimating()
        }
    }

    func hideActivityIndicator() {
        DispatchQueue.main.async {
            self.backgroundView = nil
        }
    }
}

答案 4 :(得分：2)

此代码可以帮助您:) 

   let indicator:UIActivityIndicatorView = UIActivityIndicatorView  (activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray) 
   indicator.color = UIColor .magentaColor()
   indicator.frame = CGRectMake(0.0, 0.0, 10.0, 10.0)
   indicator.center = self.view.center
   self.view.addSubview(indicator)
   indicator.bringSubviewToFront(self.view)
   indicator.startAnimating()

答案 5 :(得分：2)

SWIFT

将它放在你的班级下面：

let indicator:UIActivityIndicatorView = UIActivityIndicatorView  (activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)

将它放在你的loadView（）中：

indicator.color = UIColor .magentaColor()
indicator.frame = CGRectMake(0.0, 0.0, 10.0, 10.0)
indicator.center = self.view.center
self.view.addSubview(indicator)
indicator.bringSubviewToFront(self.view)
indicator.startAnimating()

在我的情况下，我通过func请求请求json对象，所以我把它放在该函数的末尾，以便在数据加载后删除活动指示符：

self.indicator.stopAnimating()
self.indicator.hidesWhenStopped = true

答案 6 :(得分：2)

另一种方法，在我的代码中，我为UITableView（Swift 2.3）添加了一个扩展：

extension UITableView {
    func activityIndicator(center: CGPoint = CGPointZero, loadingInProgress: Bool) {
        let tag = 12093
        if loadingInProgress {
            var indicator = UIActivityIndicatorView()
            indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
            indicator.tag = tag
            indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.WhiteLarge
            indicator.color = //Your color here
            indicator.center = center
            indicator.startAnimating()
            indicator.hidesWhenStopped = true
            self.superview?.addSubview(indicator)
        }else {
             if let indicator = self.superview?.viewWithTag(tag) as? UIActivityIndicatorView { {
                indicator.stopAnimating()
                indicator.removeFromSuperview()
            }
        }
    }
}

注意：我的tableview嵌入在UIView（superview）

中

答案 7 :(得分：1)

print("(a):{}".format(a.get('a'['b'])))

答案 8 :(得分：0)

使用＆＃34; lazy var＆＃34;。它比功能

更好 
fileprivate lazy var activityIndicatorView: UIActivityIndicatorView = {
    let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .gray)
    activityIndicatorView.hidesWhenStopped = true

    // Set Center
    var center = self.view.center
    if let navigationBarFrame = self.navigationController?.navigationBar.frame {
        center.y -= (navigationBarFrame.origin.y + navigationBarFrame.size.height)
    }
    activityIndicatorView.center = center

    self.view.addSubview(activityIndicatorView)
    return activityIndicatorView
}()

只需在任何地方启动微调器

像这样

func requestData() {
  // Request something
  activityIndicatorView.startAnimating()
}

答案 9 :(得分：0)

为了即使在最终的UITableViewController分隔符上也将UIActivityIndi​​cator放在前台，我采用了这种解决方案。

  • 我已经以编程方式添加了UIActivityIndi​​cator，并将其添加为UINavigationController的子视图

    var activityIndicator: UIActivityIndicatorView!

override func viewDidLoad() {
   super.viewDidLoad()
   // Code
   // .... omissis

   // Set activity indicator
   activityIndicator = UIActivityIndicatorView(style: .whiteLarge)
   activityIndicator.color = UIColor.darkGray
   activityIndicator.center = tableView.center
   activityIndicator.hidesWhenStopped = true
   activityIndicator.stopAnimating()
   self.navigationController?.view.addSubview(activityIndicator)
}

  • 我只是在需要时启动和停止它（对于我而言）：

    func animateActivityIndicator(_ sender: Any ) {
   guard let vc = sender as? UIViewController else { return }
   if let v = vc as? MyTableViewController {
       if v.activityIndicator.isAnimating {
           v.activityIndicator.stopAnimating()
       } else {
           v.activityIndicator.startAnimating()
       }
   }
   // Others UIViewController or UITableViewController follows...
   // all of them exhibits an activityIndicator variable
   // implemented programmatically or with the storyboard
}

PS。我的环境是Xcode 10.0，iOS 12.0

答案 10 :(得分：0)

更新Swift 4.2：

1。调用viewDidLoad上的activityIndi​​cator函数
例如：

var indicator = UIActivityIndicatorView()
override func viewDidLoad() {
    //Initializing the Activity Indicator
    activityIndicator()
    //Starting the Activity Indicator
    indicator.startAnimating()
    //Call Your WebService or API
    callAPI()
}

  1. 执行与UI相关的操作或API调用

    func callAPI() {     
    YourModelClass.fetchResult(someParams, 
    completionHandler: { (response) in 
    //Do necessary UIUpdates
    self.indicator.stopAnimating()
    })
}

3。停止活动指示器

func activityIndicator() {
            indicator = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
            indicator.style = UIActivityIndicatorView.Style.whiteLarge
            indicator.color = .red
            indicator.center = self.view.center
            self.view.addSubview(indicator)
    }

答案 11 :(得分：-1)

@brocolli对Swift 4.0的回答。在获取或设置关联对象之前，必须使用 objc _ 。根据文档，在Swift中获取和设置关联对象的API为：

func objc_getAssociatedObject(object: AnyObject!,
                                 key: UnsafePointer<Void>
                             )  -> AnyObject!

func objc_setAssociatedObject(object: AnyObject!,
                                 key: UnsafePointer<Void>,
                               value: AnyObject!,
                              policy: objc_AssociationPolicy)

实施：

import UIKit

fileprivate var ActivityIndicatorViewAssociativeKey = "ActivityIndicatorViewAssociativeKey"

extension UIView {
    var activityIndicatorView: UIActivityIndicatorView {
        get {
            if let activityIndicatorView = objc_getAssociatedObject(self, &ActivityIndicatorViewAssociativeKey) as? UIActivityIndicatorView {
                return activityIndicatorView
            } else {
                let activityIndicatorView = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
                activityIndicatorView.activityIndicatorViewStyle = .gray
                activityIndicatorView.color = .gray
                activityIndicatorView.center = center
                activityIndicatorView.hidesWhenStopped = true
                addSubview(activityIndicatorView)

                objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, activityIndicatorView, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
                return activityIndicatorView
            }
        }

        set {
            addSubview(newValue)
            objc_setAssociatedObject(self, &ActivityIndicatorViewAssociativeKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }

    }
}
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