我的代码从网络下载图像并将它们设置为 tableView 单元格 imageView。它工作正常，只是我需要点击一个单元格来刷新单元格的内容并加载图像。我希望图像在加载后立即出现。我尝试在 cellToUpdate 下添加 reloadData() 但应用程序最终陷入无限循环并崩溃。这是我的代码：
let request: NSURLRequest = NSURLRequest(URL: imgURL)
let getImage: NSURLSessionDataTask = session.dataTaskWithRequest(request, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if error == nil {
image = UIImage(data: data)
// Store the image in to our cache
self.imageCache[urlString] = image
dispatch_async(dispatch_get_main_queue(), {
if let cellToUpdate = tableView.cellForRowAtIndexPath(indexPath) {
cellToUpdate.imageView?.image = image
}
})
}
else {
println("Error: \(error.localizedDescription)")
}
})
getImage.resume()
使用以下类：
class ImageLoadingWithCache {
var imageCache = [String:UIImage]()
func getImage(url: String, imageView: UIImageView, defaultImage: String) {
if let img = imageCache[url] {
imageView.image = img
} else {
let request: NSURLRequest = NSURLRequest(URL: NSURL(string: url)!)
let mainQueue = NSOperationQueue.mainQueue()
NSURLConnection.sendAsynchronousRequest(request, queue: mainQueue, completionHandler: { (response, data, error) -> Void in
if error == nil {
let image = UIImage(data: data)
self.imageCache[url] = image
dispatch_async(dispatch_get_main_queue(), {
imageView.image = image
})
}
else {
imageView.image = UIImage(named: defaultImage)
}
})
}
}
}
Usage:
var cache = ImageLoadingWithCache()
cache.getImage(YOUR_URL, imageView: YOUR_IMAGEVIEW, defaultImage: "DEFAULT_IMAGE_NAME")
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
