如何在UICollectionViewCell中使用详细披露button？

我试图使用下面的图片（PhotoSearchViewController）的视图控制器上的详细披露button来显示一个UIAlertController，它显示从ImageUrlItem的照片说明。

当我点击button时，它显示它被按下，但是包含描述的警报没有出现。

我的代码ImageUrlItem：

import Foundation import Firebase struct ImageUrlItem { //Should I add my description in here? let key: String let imageUrl: String let watsonCollectionImageUrl: String let score: Double let description: String let ref: FIRDatabaseReference? init(imageUrl: String, key: String = "", watsonCollectionImageUrl: String = "", score: Double = 0, description: String) { self.key = key self.imageUrl = imageUrl self.watsonCollectionImageUrl = watsonCollectionImageUrl self.ref = nil self.score = score self.description = description } init(snapshot: FIRDataSnapshot) { key = snapshot.key let snapshotValue = snapshot.value as! [String: AnyObject] imageUrl = snapshotValue["ImageUrl"] as! String // must map to firebase names watsonCollectionImageUrl = "" score = 0 description = snapshotValue["Description"] as! String ref = snapshot.ref } func toAnyObject() -> Any { return [ "imageUrl": imageUrl, "Description": description ] } } 

我收集视图单元格（PhotoCell）的代码如下：

 class PhotoCell: UICollectionViewCell, UIAlertViewDelegate { var photos: [ImageUrlItem] = [] var ref = FIRDatabase.database().reference(withPath: "Photos") @IBOutlet weak var imgPhoto: UIImageView! @IBOutlet weak var lblScore: UILabel! @IBAction func btnDesc(_ sender: UIButton) { let alertTitle = "Description" let alertMessage = photos.description let alertController = UIAlertController(title: alertTitle, message: alertMessage, preferredStyle: UIAlertControllerStyle.alert) let okAction = UIAlertAction(title:"Ok", style: UIAlertActionStyle.default) { (result : UIAlertAction) -> Void in print("OK") } alertController.addAction(okAction) self.parentViewController?.present(alertController, animated: true, completion: nil) } } 

我的PhotoSearchViewController中的cellForRowAt代码：

  func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let reuseIdentifier = "PhotoCell" let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! PhotoCell cell.backgroundColor = UIColor(red:0.74, green:0.76, blue:0.78, alpha: 1.0) // Do any custom modifications you your cell, referencing the outlets you defined in the Custom cell file // if we have a label IBOutlet in PhotoCell we can customize it here // on page load when we have no search results, show nothing if similarImageUrls.count > 0 { //print(indexPath.row) //print(similarImageUrls.count) if (indexPath.row < similarImageUrls.count){ let image = self.similarImageUrls[indexPath.row] // get image asynchronously via URL let url = URL(string: image.imageUrl) DispatchQueue.global().async { // make an asynchonorous call to load the image DispatchQueue.main.async { cell.imgPhoto.af_setImage(withURL: url!) // show image using alamofire } } cell.lblScore.isHidden = false cell.lblScore.text = "Score: \(NSString(format: "%.2f", (image.score * 100)) as String)%" } else { // show the placeholder image instead cell.imgPhoto.image = UIImage(named: "person") cell.lblScore.isHidden = true cell.lblScore.text = "0.00%" } } else { // show the placeholder image instead cell.imgPhoto.image = UIImage(named: "person") cell.lblScore.isHidden = true cell.lblScore.text = "0.00%" // when we get to the last image, and it is not the first time load if (indexPath.row == 8 && !firstTimeSearch){ // show nothing found alert here let ac = UIAlertController(title: "Photo Search Completed!", message:"No macthing photo found!", preferredStyle: .alert) ac.addAction(UIAlertAction(title: "OK", style: .default)) self.present(ac, animated: true) } } return cell } } 

Answer 1

您可以使用自定义委托显示警报

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  // here is the protocol for creating the delegation: protocol BtnDesc : class { func btnDecAlert(alertTitle: String, message: String) } 

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  class PhotoCell: UICollectionViewCell { // MARK:- Delegate weak var btnDescDelegate : BtnDesc? var photos: [ImageUrlItem] = [] var ref = FIRDatabase.database().reference(withPath: "Photos") @IBOutlet weak var imgPhoto: UIImageView! @IBOutlet weak var lblScore: UILabel! @IBAction func btnDesc(_ sender: UIButton) { let alertTitle = "Description" let alertMessage = photos.description btnDescDelegate?.btnDecAlert(alertTitle: alertTitle, message: alertMessage) } } 

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PhotoSearchViewController中的cellForRowAt代码：

 func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let reuseIdentifier = "PhotoCell" let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath as IndexPath) as! PhotoCell //Mark set the delegate. cell.btnDescDelegate = self ..... 

---

  //conform delegate extension PhotoSearchViewController : BtnDesc { func btnDecAlert(alertTitle: String, message: String) { let alert = UIAlertController(title: alertTitle, message: message, preferredStyle: .alert) let okAction = UIAlertAction(title: "Ok", style: .default, handler: {(_ action: UIAlertAction) -> Void in // here is your action print("OK") }) alert.addAction(okAction) self.present(alert, animated: true, completion: nil) } }