如何在单元格中调用图像 url 和图像视图以获取集合视图的索引路径功能

Posted 2023-03-03

【中文标题】如何在单元格中调用图像 url 和图像视图以获取集合视图的索引路径功能

【英文标题】：How to call image urls and image view in cell for index path function for a collection view

【发布时间】：2016-08-22 11:50:54

【问题描述】：

我想在一个集合视图中异步调度 8 个图像 url。我为集合视图单元创建了一个类，并在其中创建了一个 imageview 的出口。现在我想从主视图控制器配置图像视图。这是代码

    let reuseIdentifier = "PhotosCollectionViewCell" // also enter this string as the cell identifier in the storyboard
   var items = ["1", "2", "3", "4", "5", "6", "7", "8"]

    // tell the collection view how many cells to make
    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int 
       return self.items.count

    

    // make a cell for each cell index path
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell 

        // get a reference to our storyboard cell
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! PhotosCollectionViewCell


        cell.imageView = imageView

        return cell



    

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) 
        // handle tap events
        print("You selected cell #\(indexPath.item)!")
    



    func loadImage() 
        dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0)) 
            let urlString = "http://charcoaldesign.co.uk/AsyncImageView/Forest/IMG_0352.JPG"
            let url = NSURL(string: urlString)
            let data = NSData(contentsOfURL: url!)
            dispatch_async(dispatch_get_main_queue(), 
             self.imageView.image = UIImage(data: data!)
//              self.items[0] = (data as? String)!

            )

        
    

【问题讨论】：

在集合视图中使用 UIImageView+WebCache 异步图像

【参考方案1】：

这是一个让事情变得更简单的扩展。

extension UIImageView 
    func downloadImageFrom(link link:String, contentMode: UIViewContentMode) 
        NSURLSession.sharedSession().dataTaskWithURL( NSURL(string:link)!, completionHandler: 
            (data, response, error) -> Void in
            dispatch_async(dispatch_get_main_queue()) 
                self.contentMode =  contentMode
                if let data = data  self.image = UIImage(data: data) 
            
        ).resume()
    


cell.imageView.downloadImageFrom(link: imageLinkArray[indexPath.row], contentMode: UIViewContentMode.ScaleAspectFit)  //set your image from link array.

您还可以查看以下网址以获得更多帮助。how to implement lazy loading of images in table view using swift

【参考方案2】：

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell 

    // get a reference to our storyboard cell
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! PhotosCollectionViewCell


    cell.imageView = imageView
    loadImage(imageView, urlPAssed: urlString)
    return cell

     func loadImage(imageViewObj : UIImageView , urlPAssed : NSString) 

    //let urlString = "http://charcoaldesign.co.uk/AsyncImageView/Forest/IMG_0352.JPG"
    let url = NSURL(string: urlPAssed as String)
    NSURLSession.sharedSession().dataTaskWithURL(url!)  (data, response, error) in
        if(error==nil)
        
            dispatch_async(dispatch_get_main_queue(),  () -> Void in
                imageViewObj.image = UIImage(data: data!)

            )
        
        else
        
            imageViewObj.image = UIImage(named: "dummy")
        
        .resume()
     

【讨论】：

感谢您的回复。这里我有 8 个图像 url 我如何运行一个循环，以便我可以在集合视图中显示 8 个图像-good4pc

像这样将您的 imageurl 与 imageView 一起传递，因此它将根据您的 collectionViewCell 动态调用。 loadImage(imageView, url) , func loadImage(imageViewObj : UIImageView , url : NSString)

我遇到很多错误请给我详细的解决方案