UICollectionViewCell中的UICollectionViewCell中創建的滾動後編程方式重疊

Question

在此處輸入代碼我試圖在swift中編程創建UICollectionView，然後將一些圖像添加到UICollectionViewCell（s）。顯示效果很好，但當我向下滾動視圖並再次回來時，單元格開始顯示疊加在另一個上的圖像（較新的圖像與較舊的圖像重疊）。我讀到引起這個問題的意見回收。我嘗試了很多，但找不到解決方案。 我請大家請幫我找到一個解決方案

感謝

// 
// ViewController1.swift 
// Gridtest 

import UIKit 

class ViewController1: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout { 

    var collectionView: UICollectionView! 

    var tapStatusHolderArray: Array<Bool> = [Bool]() 
    var cellCaptureArray: Array<UICollectionViewCell> = [UICollectionViewCell]() 
    var accountsIdHohderArray: Array<Int16> = [Int16]() 
    var accountsNameHolderArray: Array<String> = [String]() 
    var providerNameHolderArray: Array<String> = [String]() 
    var accountStatusHolderArray: Array<String> = [String]() 
    var accountsImageNameHolder: Array<String> = [String]() 
    override func viewDidLoad() { 
     super.viewDidLoad() 


     //data loader open 
     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(100) 
     accountsNameHolderArray.append("account 1") 
     providerNameHolderArray.append("twitter") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(101) 
     accountsNameHolderArray.append("account 2") 
     providerNameHolderArray.append("facebook") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(102) 
     accountsNameHolderArray.append("account 3") 
     providerNameHolderArray.append("linkedin") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(100) 
     accountsNameHolderArray.append("account 1") 
     providerNameHolderArray.append("twitter") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(101) 
     accountsNameHolderArray.append("account 2") 
     providerNameHolderArray.append("facebook") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(102) 
     accountsNameHolderArray.append("account 3") 
     providerNameHolderArray.append("linkedin") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(100) 
     accountsNameHolderArray.append("account 1") 
     providerNameHolderArray.append("twitter") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(101) 
     accountsNameHolderArray.append("account 2") 
     providerNameHolderArray.append("facebook") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 

     tapStatusHolderArray.append(false) 
     accountsIdHohderArray.append(102) 
     accountsNameHolderArray.append("account 3") 
     providerNameHolderArray.append("linkedin") 
     accountStatusHolderArray.append("enabled") 
     accountsImageNameHolder.append("default_user_image") 
     //data loader close 


     // Do any additional setup after loading the view. 
     let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout() 
     layout.sectionInset = UIEdgeInsets(top: 20, left: 10, bottom: 10, right: 10) 
     layout.itemSize = CGSize(width: 70, height: 70) 

     collectionView = UICollectionView(frame: CGRect(x: self.view.frame.origin.x, y: self.view.frame.origin.y, width: 200, height: 200), collectionViewLayout: layout) 
     collectionView.dataSource = self 
     collectionView.delegate = self 
     collectionView.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell") 
     collectionView.backgroundColor = UIColor.whiteColor() 
     self.view.addSubview(collectionView) 
    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 


    /* 
    // MARK: - Navigation 

    // In a storyboard-based application, you will often want to do a little preparation before navigation 
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 
     // Get the new view controller using segue.destinationViewController. 
     // Pass the selected object to the new view controller. 
    } 
    */ 

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 
     return self.tapStatusHolderArray.count 
    } 

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell { 
     let cell: UICollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! UICollectionViewCell 
     cell.backgroundColor = UIColor.yellowColor() 

     //create views here 
     let accountsImageView = UIImageView() 
     accountsImageView.setTranslatesAutoresizingMaskIntoConstraints(false) 
     accountsImageView.image = UIImage(named: "default_user_image") 

     //tap listener for the accounts image view 
     let tapAccountsImageView = UITapGestureRecognizer(target: self, action: Selector("tapGesture:")) 
     accountsImageView.tag = indexPath.row 
     accountsImageView.addGestureRecognizer(tapAccountsImageView) 
     accountsImageView.userInteractionEnabled = true 


     let providerImageView = UIImageView() 
     providerImageView.setTranslatesAutoresizingMaskIntoConstraints(false) 
     providerImageView.image = UIImage(named: translateProviderNameToImageName(providerNameHolderArray[indexPath.row])) 

     let checkboxImageView = UIImageView() 
     checkboxImageView.setTranslatesAutoresizingMaskIntoConstraints(false) 
     checkboxImageView.image = UIImage(named: "checkbox_unchecked") 

     //tap listener for the checkbox image view 
     let tapCheckbox = UITapGestureRecognizer(target: self, action: Selector("tapGesture:")) 
     checkboxImageView.tag = indexPath.row 
     checkboxImageView.addGestureRecognizer(tapCheckbox) 
     checkboxImageView.userInteractionEnabled = true 
     /************************************************************/ 

     //add subviews here 
     cell.addSubview(accountsImageView) 
     cell.addSubview(providerImageView) 
     cell.addSubview(checkboxImageView) 
     /************************************************************/ 


     //view dictionary 
     let viewsDictionary = [ 
      "accountsImageView":accountsImageView, 
      "providerImageView":providerImageView, 
      "checkboxImageView":checkboxImageView 
     ] 
     /************************************************************/ 




     //apply size constraints 
     //accountsImageView 
     //1 
     let accountsImageView_constraint_H = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:[accountsImageView(50)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, 
      views: viewsDictionary) 
     let accountsImageView_constraint_V = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:[accountsImageView(50)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 

     accountsImageView.addConstraints(accountsImageView_constraint_H) 
     accountsImageView.addConstraints(accountsImageView_constraint_V) 

     //2 
     let providerImageView_constraint_H = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:[providerImageView(20)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, 
      views: viewsDictionary) 
     let providerImageView_constraint_V = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:[providerImageView(20)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 

     providerImageView.addConstraints(providerImageView_constraint_H) 
     providerImageView.addConstraints(providerImageView_constraint_V) 


     //3 
     let checkboxImageView_constraint_H = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:[checkboxImageView(20)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, 
      views: viewsDictionary) 
     let checkboxImageView_constraint_V = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:[checkboxImageView(20)]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 

     checkboxImageView.addConstraints(checkboxImageView_constraint_H) 
     checkboxImageView.addConstraints(checkboxImageView_constraint_V) 
     /**************************************************************/ 

     //position constraints 

     //views 

     //1 
     let view_constraint_H = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-[accountsImageView]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 
     let view_constraint_V = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:|-[accountsImageView]", 
      options: NSLayoutFormatOptions.AlignAllLeading, 
      metrics: nil, views: viewsDictionary) 

     cell.addConstraints(view_constraint_H) 
     cell.addConstraints(view_constraint_V) 




     //2 
     let view_constraint_H1 = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-45-[providerImageView]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 
     let view_constraint_V1 = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:[providerImageView]-50-|", 
      options: NSLayoutFormatOptions.AlignAllLeading, 
      metrics: nil, views: viewsDictionary) 

     cell.addConstraints(view_constraint_H1) 
     cell.addConstraints(view_constraint_V1) 


     //3 
     let view_constraint_H2 = NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-0-[checkboxImageView]", 
      options: NSLayoutFormatOptions(rawValue:0), 
      metrics: nil, views: viewsDictionary) 
     let view_constraint_V2 = NSLayoutConstraint.constraintsWithVisualFormat(
      "V:[checkboxImageView]-5-|", 
      options: NSLayoutFormatOptions.AlignAllLeading, 
      metrics: nil, views: viewsDictionary) 

     cell.addConstraints(view_constraint_H2) 
     cell.addConstraints(view_constraint_V2) 
     /***************************************************************/ 


     //set initial status for the cell checkbox 
     if(tapStatusHolderArray[indexPath.row] == true){ 
      //set the checkbox as checked 
      checkboxImageView.image = UIImage(named: "checked_checkbox") 
     }else{ 
      //set checkbox as unchecked 
      checkboxImageView.image = UIImage(named: "checkbox_unchecked") 
     } 

     //load the cell into the array 
     cellCaptureArray.append(cell) 
     return cell 
    } 

    func tapGesture(sender: UITapGestureRecognizer) 
    { 
     /*var index: Int = sender.view!.tag 
     if(checkedStatusHolderArray[index] == false){ 
     checkedStatusHolderArray[index] = true 
     (sender.view as! UIImageView).image = UIImage(named: "checked_checkbox") 
     }else{ 
     checkedStatusHolderArray[index] = false 
     (sender.view as! UIImageView).image = UIImage(named: "checkbox_unchecked") 
     }*///old code 

     /* 
     this code extracts the index from the tag attached to the sender 
     In this case the sender could be either the checkboxIV or the accountIV 
     both have the same tag. The tag is the indexpath.row for the corresponding cell. 
     The indexpath.row is used to signal the tap gesture recognizer about the view being tapped. 
     The tap gesture recognizer is asigned to both the views checkboxIV and the accountIV 
     so that the user can tap on either to allow check and uncheck the checkbox. Both the tap 
     gestures reconizers do the same function. 
     The cell inflated are saved inside the checkedStatusHolderArray so that using the index 
     extracted above we can change the status of the checkboxIV of the corresponding cell. 
     */ 
     var index: Int = sender.view!.tag 
     var cell: UICollectionViewCell = cellCaptureArray[index] 

     if(tapStatusHolderArray[index] == false){ 
      tapStatusHolderArray[index] = true 

      let subViews = cell.subviews 
      //assuming that the order in which the views were added will be maintained 
      let checkboxIV = subViews[3] as! UIImageView 
      checkboxIV.image = UIImage(named: "checked_checkbox") 
     }else{ 
      tapStatusHolderArray[index] = false 

      let subViews = cell.subviews 
      //assuming that the order in which the views were added will be maintained 
      let checkboxIV = subViews[3] as! UIImageView 
      checkboxIV.image = UIImage(named: "checkbox_unchecked") 
     } 

     /*the reson for choosing [3] for the subvies is that at 
     index 0 the superview is present 
     index 1 the accountsImageView is present 
     index 2 the providerImageView is present 
     index 3 the checkboxImageView is present*/ 
    } 

    func translateProviderNameToImageName(var provider: String) -> String{ 
     switch provider{ 
     case "twitter": 
      return "twitter_transparent" 

     case "facebook": 
      return "facebook_transparent" 

     case "linkedin": 
      return "linkedin-follow" 

     default: 
      return "twitter_transparent" 
     } 
    } 
} 

Answer 1

第一復位ImageView的（此代碼可通過添加具有名稱一些圖像上運行），然後嘗試加載

UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath]; 
cell.imageView.image = nil; 
cell.imageView.image = [UIImage imagewithNamed:@"imagename"];