How to show activity indicator while tableView loads?

问题:

When I switch between my tabs it loads some seconds and I want to know that my data is loading. For that I decided to add an activity indicator.

I wrote a little function:

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()     } }

that will show my indicator. And try to use it when I tapped from my infoController to button:

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

I show it before segue perform and hide after. It doesn't help me. When I did try to use sync:

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

But it doesn't help too. When I press to tab it opacity becomes 0.5 and I wait while it loading. But I do not see my activity indicator.

What is the problem?

回答1:

Just try this:

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)     }

And where you want to start animating

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

For stop:

indicator.stopAnimating() indicator.hidesWhenStopped = true

Note: Avoid the calling of start and stop in same time. Just give some conditions.

回答2:

Swift 3.0

// UIView Extension

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 Extension

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     } }

start animation

tableView.activityIndicatorView.startAnimating()

stop animation

tableView.activityIndicatorView.stopAnimating()

You can find more code in Magic

回答3:

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()          }         ...     }

回答4:

This code can help you :)

   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()

回答5:

SWIFT

Place this below your class:

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

Place this in your loadView():

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()

In my case, I am requesting json objects through a func request, so I placed this at the end of that function to remove the activity indicator once the data loads:

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

回答6:

Another approach, In my code I added an extension for UITableView (Swift 2.3) :

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()             }         }     } }

Note : My tableview is embedded in a UIView (superview)

回答7:

 func setupSpinner(){     spinner = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 40, height:40))     spinner.color = UIColor(Colors.Accent)     self.spinner.center = CGPoint(x:UIScreen.main.bounds.size.width / 2, y:UIScreen.main.bounds.size.height / 2)     self.view.addSubview(spinner)     spinner.hidesWhenStopped = true }

回答8:

Using "lazy var". It's better than function

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 }()

Just start the spinner anywhere

like this

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

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