IOS：在web视图中添加活动指示器视图

我猜你的

mySpinner

ivar没有被正确地保留或声明

在.h文件中，将其声明为属性。即:

    class ViewController: UIViewController , UIWebViewDelegate {
          var  webview = UIWebView()
          var boxView = UIView()
           @IBAction func webview(sender: UIButton) {
                 let activityView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)        
                 activityView.frame = CGRect(x: 20, y: 12, width: 40, height: 40)
                 activityView.startAnimating()
                webview.addSubview(activityView)
                webview.reload()
                let url = NSURL(string:"http://www.sugoilabs.com")
                       UIApplication.sharedApplication().openURL(url!)    
                }
                override func viewDidLoad() {
                      super.viewDidLoad()
               // Do any additional setup after loading the view, typically from a nib.
                }
                func webViewDidStartLoad(webView_Pages: UIWebView) {
                      webview.delegate = self
                     // Box config:
                     boxView = UIView(frame: CGRect(x: 115, y: 110, width: 80, height: 80))
                     boxView.backgroundColor = UIColor.blackColor()
                     boxView.alpha = 1
                     boxView.layer.cornerRadius = 10
                    // Spin config:
                    let activityView = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
                    activityView.frame = CGRect(x: 20, y: 12, width: 40, height: 40)
                    activityView.startAnimating()
                   // Text config:
                   let textLabel = UILabel(frame: CGRect(x: 0, y: 50, width: 80, height: 30))
                  textLabel.textColor = UIColor.blackColor()
                  textLabel.textAlignment = .Center
                  textLabel.font = UIFont(name: textLabel.font.fontName, size: 13)
                  textLabel.text = "Loading..."

                  // Activate:
                 boxView.addSubview(activityView)
                 boxView.addSubview(textLabel)
                 self.view.addSubview(boxView)
             }
            func webViewDidFinishLoad(webView_Pages: UIWebView) {
                  // Removes it:
                  boxView.removeFromSuperview()

           }
  }

然后，当您创建它时：

@property (strong) UIActivityIndicatorView *mySpinner;

当您在按钮单击方法中引用它时：

self.mySpinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

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请删除这些白线。它很难读！最后，有什么问题吗？

[self.mySpinner startAnimating];