ios - 向图像 Auk lib 添加描述

Question

我正在使用 Auk lib 在 slider 中呈现我的图像，我需要为每个图像设置描述。我怎样才能简单地做到这一点？现在我尝试下载图像，然后在其上设置描述:

    override func viewDidLoad() {
        super.viewDidLoad()

        for picture in LogInViewController.dictionaryForSlider
        {
            //scrollView.auk.show(url: picture.key, accessibilityLabel: picture.value)
            let downloadedPic: UIImage = self.downloadImage(urlStr: picture.key)
            let newPic: UIImage = self.textToImage(drawText: picture.value as NSString, inImage: downloadedPic, atPoint: CGPoint(x: 10, y: 10))

            scrollView.auk.show(image: newPic)
        }

    }


    func textToImage(drawText text: NSString, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
        let textColor = UIColor.white
        let textFont = UIFont(name: "Helvetica Bold", size: 12)!

        let scale = UIScreen.main.scale
        UIGraphicsBeginImageContextWithOptions(image.size, false, scale)

        let textFontAttributes = [
            NSFontAttributeName: textFont,
            NSForegroundColorAttributeName: textColor,
            ] as [String : Any]
        image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))

        let rect = CGRect(origin: point, size: image.size)
        text.draw(in: rect, withAttributes: textFontAttributes)

        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage!
    }

    func downloadImage(urlStr: String) -> UIImage {
        var img: UIImage? = nil
        var imgURL: NSURL = NSURL(string: urlStr)!
        let request: NSURLRequest = NSURLRequest(url: imgURL as URL)
        NSURLConnection.sendAsynchronousRequest(
            request as URLRequest, queue: OperationQueue.main,
            completionHandler: { response,data,error in
                if error == nil {
                    img = UIImage(data: data!)
                }
        })
        return img!
    }

但是我收到了这个错误:

2017-03-25 08:02:04.627615 app1[314:25451] fatal error: unexpectedly found nil while unwrapping an Optional value

在此字符串上:

return img!

我该如何解决这个问题？或者还有其他简单的方法来为图像设置描述吗？

Answer 1

我已经处理了它，没有任何额外的库/GB 代码 XD 只需使用 UIScrollViewDelegate

import UIKit
import Auk

class SliderViewController: UIViewController, UIScrollViewDelegate {


    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var labelForInfo: UILabel!
    @IBOutlet weak var navBarTitle: UINavigationItem!

    var lastPoint: CGPoint?
    var listForDescr: [Int : String] = [Int : String]()

    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        lastPoint = scrollView.contentOffset
    }
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        if (lastPoint?.x)! < scrollView.contentOffset.x {
            //print(scrollView.auk.currentPageIndex ?? 0)
            navBarTitle.title = listForDescr[scrollView.auk.currentPageIndex ?? 0]
        }
        else if (lastPoint?.x)! > scrollView.contentOffset.x {
            //print(scrollView.auk.currentPageIndex ?? 0)
            navBarTitle.title = listForDescr[scrollView.auk.currentPageIndex ?? 0]
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        self.scrollView.delegate = self

        labelForInfo.text = ""
        scrollView.backgroundColor = UIColor.white
        var count: Int = 0
        for picture in LogInViewController.dictionaryForSlider
        {
            scrollView.auk.show(url: picture.key, accessibilityLabel: picture.value)
            listForDescr.updateValue(picture.value, forKey: count)
            count+=1
        }

    }


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

}