UIAlertController：它不会在一个控件中关闭一个UICollectionView

Posted 2021-04-21

我创建了一个类«Chargement»，它允许显示带有加载的警报并关闭它。

import Foundation
class Chargement {
    var alert : UIAlertController;
    var message : String = NSLocalizedString("PleaseWait", comment:"") ;
    let loadingIndicator : UIActivityIndicatorView;
    init(message : String?) {
        if(message != nil){
            self.message = message!;
        }
        self.alert = UIAlertController(title: nil, message: self.message, preferredStyle: UIAlertControllerStyle.alert)
        self.loadingIndicator = UIActivityIndicatorView(frame: CGRect(x: 10, y: 4, width: 40, height: 60))

    }
    func showLoading(view : UIViewController){
        loadingIndicator.hidesWhenStopped = true
        loadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.gray
        loadingIndicator.startAnimating();
        alert.view.addSubview(loadingIndicator)
        view.present(alert, animated: true, completion: nil)
    }
    func closeLoading(){
        alert.dismiss(animated: true, completion: nil)
    }
}

当我在没有UICollectionView的controllerView中使用我的类“Chargement”时，它可以用作例如：

class ViewController : UIViewController{
 let loadingView : Chargement = Chargement(message: nil);
 override func viewDidLoad() {
   super.viewDidLoad();
   loadingView.showLoading(view: self);
  }

  @IBAction func btn_Action(_ sender: UIButton) {
        self.loadingView.closeLoading();//it works
    }
}

但是当我在带有UICollectionView的controllerView中使用它时，警报显示有效，但它不会关闭。

class TTwoViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout  {
 let loadingView : Chargement = Chargement(message: nil);
 @IBOutlet weak var collectionView: UICollectionView!
 override func viewDidLoad() {
        super.viewDidLoad();
        loadingView.showLoading(view: self);
        loadingData();
    }
 func loadingData() {
        dataManager().getData(num: 1, completion: {
            (data, messages) in
                   self.loadingView.closeLoading(); //it don't work
                DispatchQueue.main.async(execute: {
                    self.collectionView.reloadData();
                   //self.loadingView.closeLoading(); //it don't work
                })
        })
    }

}

答案

如果您只想显示活动指示器，可以使用NVActivityIndicatorView简化整个过程：

override func viewDidLoad() {
    super.viewDidLoad();
    let activityData = ActivityData()
    NVActivityIndicatorPresenter.sharedInstance.startAnimating(activityData)
    NVActivityIndicatorPresenter.sharedInstance.setMessage("Please Wait")
    loadingData();
}

func loadingData() {
    dataManager().getData(num: 1, completion: { (data, messages) in
        DispatchQueue.main.async {
             self.collectionView.reloadData()
             NVActivityIndicatorPresenter.sharedInstance.stopAnimating()
        }
    })
}