问题:

我有一个 CollectionView，它将 UIimage 加载到每个单元格中。但是我的问题是，当我加载带有更多图像的其他单元格时，它们似乎是重复的。我不太明白是什么导致了我的代码中出现这种情况。 可能是因为可重复使用的电池有问题吗？

谁能看出为什么会这样？

注意:包含图像的数组没有重复项

问题视频: https://www.youtube.com/watch?v=vjRsFc8DDmI

问题图片:

这是我的 collectionView 函数:

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    //#warning Incomplete method implementation -- Return the number of items in the section
    if self.movies == nil
    {
      return 0

    }

    return self.movies!.count

}

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell 
{
    let cell =    
      collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, 
        forIndexPath: indexPath) as! UpcomingCollectionViewCell

   if self.movies != nil && self.movies!.count >= indexPath.row
    {
        // Calc size of cell
        cell.frame.size.width = screenWidth / 3
        cell.frame.size.height = screenWidth / 3 * 1.54

        let movies = self.movies![indexPath.row]
        if(movies.posterPath != "" || movies.posterPath != "null"){
        cell.data = movies.posterPath
        }
        else{
        cell.data = nil
        }
        // See if we need to load more movies
        let rowsToLoadFromBottom = 5;
        let rowsLoaded = self.movies!.count
        if (!self.isLoadingMovies && (indexPath.row >= (rowsLoaded - rowsToLoadFromBottom)))
        {
            let totalRows = self.movieWrapper!.totalResults!
            let remainingMoviesToLoad = totalRows - rowsLoaded;
            if (remainingMoviesToLoad > 0)
            {
                self.loadMoreMovies()
            }
        }
}
   else
{
        cell.data = nil
}

    return cell
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
{
    return CGSize(width: screenWidth/3, height: screenWidth/3*1.54)
}

这里我从 Wrapper 类加载数据:

func loadFirstMovies()
{

    isLoadingMovies = true

    Movies.getMovies({ (movieWrapper, error) in
        if error != nil
        {
            // TODO: improved error handling
            self.isLoadingMovies = false
            let alert = UIAlertController(title: "Error", message: "Could not load first movies \(error?.localizedDescription)", preferredStyle: UIAlertControllerStyle.Alert)
            alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
            self.presentViewController(alert, animated: true, completion: nil)
        }
        self.addMoviesFromWrapper(movieWrapper)
        self.activityIndicator.hidden = true
        self.isLoadingMovies = false
        self.collectionView.reloadData()
    })
}

func loadMoreMovies(){

    self.isLoadingMovies = true
    if self.movies != nil && self.movieWrapper != nil && self.movieWrapper!.page < self.movieWrapper!.totalPages
    {
        // there are more species out there!
        Movies.getMoreMovies(self.movieWrapper, completionHandler: { (moreWrapper, error) in
            if error != nil
            {
                // TODO: improved error handling
                self.isLoadingMovies = false
                let alert = UIAlertController(title: "Error", message: "Could not load more movies \(error?.localizedDescription)", preferredStyle: UIAlertControllerStyle.Alert)
                alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
                self.presentViewController(alert, animated: true, completion: nil)
            }
            print("got more!")
            self.addMoviesFromWrapper(moreWrapper)
            self.isLoadingMovies = false
            self.collectionView.reloadData()
        })
    }
}

func addMoviesFromWrapper(wrapper: MovieWrapper?)
{
    self.movieWrapper = wrapper
    if self.movies == nil
    {
        self.movies = self.movieWrapper?.results
    }
    else if self.movieWrapper != nil && self.movieWrapper!.results != nil
    {
        self.movies = self.movies! + self.movieWrapper!.results!
    }
}

最后我在 viewDidLoad()

编辑: 即将到来的 CollectionViewCell

class UpcomingCollectionViewCell: UICollectionViewCell {

@IBOutlet weak var imageView: UIImageView!


var data:String?{
    didSet{
        self.setupData()
    }
}

func setupData(){

   self.imageView.image = nil // reset the image

    if let urlString = data{
        let url =  NSURL(string: "http://image.tmdb.org/t/p/w342/" + urlString)
        self.imageView.hnk_setImageFromURL(url!)


      }
    }  
 }

最佳答案

这是典型的 TableView / Collection View 设置问题。

任何时候您使用像 dequeueReusableCellWithReuseIdentifier: 这样的出列方法回收单元格时，您必须始终完全配置单元格中的所有 View ，包括将所有文本字段/ ImageView 设置为它们的起始值。您的代码有几个 if 语句，如果 if 的条件为假，则您不会在单元格中设置 View 。您需要使用 else 子句从单元格的 View 中清除旧内容，以防上次使用单元格时留下内容。

编辑:

更改您的 cellForItemAtIndexPath 方法，使其像这样开始:

func collectionView(collectionView: UICollectionView, 
  cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell 
{
    let cell =    
      collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, 
        forIndexPath: indexPath) as! UpcomingCollectionViewCell
    cell.imageView.image = nil;  //Remove the image from the recycled cell
//The rest of your method ...

关于ios - 加载更多数据时 CollectionView 重复单元格，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33674788/