在iPad中选择图片后出现无错误（适用于iPhone）

Question

当我使用照片库时，由于使用相机的iPad问题，我的应用程序被iTunes拒绝了。出于某种原因，它在didFinishPickingMediaWithInfo方法中崩溃。它适用于iPhone，但我不确定为什么它在iPad上无效。

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {

    if(picker.sourceType == UIImagePickerControllerSourceType.PhotoLibrary)
    {  
        //Crashing here -> "fatal error: unexpectedly found nil while unwrapping an Optional value"
        var selectedImage: UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage

        appraisalPic.backgroundColor = UIColor.blackColor();
        appraisalPic.image = selectedImage

        self.dismissViewControllerAnimated(true, completion: nil)


    }

Answer 1

使用下面给出的代码而不是上面的代码，它可能会帮助你。

  func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {

            if(picker.sourceType == UIImagePickerControllerSourceType.PhotoLibrary)
            {  

               let url: NSString = info[UIImagePickerControllerReferenceURL] as NSString
               var imageName:String = url.lastPathComponent       
               let nsDocumentDirectory = NSSearchPathDirectory.DocumentDirectory
               let nsUserDomainMask    = NSSearchPathDomainMask.UserDomainMask

               if let paths = NSSearchPathForDirectoriesInDomains(nsDocumentDirectory, nsUserDomainMask, true) {
                  if paths.count > 0 {
                    if let dirPath = paths[0] as? String {
                    let readPath = dirPath.stringByAppendingPathComponent(imageName)
                    var pickedimage = UIImage(CGImage: UIImage(contentsOfFile: readPath)!.CGImage, scale: 1.0, orientation: .Up)
                    appraisalPic.backgroundColor = UIColor.blackColor();
                    appraisalPic.image = pickedimage
                }
            }
      }
 }

Answer 2

发生崩溃是因为您强制在后续行中展开可选值：

var selectedImage: UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage

尝试按如下方式重写代码：

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {

    guard let selectedImage = info[UIImagePickerControllerOriginalImage] as? UIImage where picker.sourceType == .PhotoLibrary else {
        return
    }

    appraisalPic.backgroundColor = UIColor.blackColor()
    appraisalPic.image = selectedImage

    self.dismissViewControllerAnimated(true, completion: nil)
}

顺便说一句：你是否正确设置了picker.sourceType？

let picker = UIImagePickerController()
override func viewDidLoad() {
    super.viewDidLoad()
    // ...
    picker.sourceType = .PhotoLibrary
    // ...
}

另请阅读GitHub's Swift Style Guide，尤其是Avoid Using Force-Unwrapping of Optionals。

Answer 3

在iPad上，您必须使用presentViewController

显示图像选择器

这是我在iPhone和iPad上展示的Obj-c代码。

        entryInsulinsArray.forEach(function(entry) {
            var entryPair = entry.split(",");
            var date = parseFloat(entryPair[0]);
            var value = entryPair[1];

            var data = {
                x: moment(date).format("HH:mm"),
                y: entryPair[1]
            }

            result.push(entryPair[1]);
        });