Question

我正在尝试使用UIImagePickerController选择图像。我有以下代码，其中有一个UIImageView的IBOutlet。

在didFinishPickingMediaWithInfo中选择图像后，我在内存中获取图像，但不知何故，它在imageview中不可见。我确实尝试在didFinishPickingMediaWithInfo中更改静态图像以进行imageview，但它也没有显示图像。代码如下，

class SnapshotViewController: UIViewController,UINavigationControllerDelegate, UIImagePickerControllerDelegate
{
    @IBOutlet var imageView: UIImageView!
    @IBAction func takePhoto(sender: AnyObject) {
      let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.sourceType = .PhotoLibrary
        imagePicker.allowsEditing = false
        presentViewController(imagePicker, animated: true, completion: nil)
    }


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

        dismissViewControllerAnimated(true, completion: nil)
        dispatch_async(dispatch_get_main_queue())
        {
            let image = info[UIImagePickerControllerOriginalImage] as? UIImage
            self.imageView.image = image
        }
    }
}

我想这是一般性问题，无论我在didFinishPickingMediaWithInfo中为此imageView更改的图像都无效。如果我在viewDidLoad中更改imageView图像，那么它的工作原理。任何人都可以请求帮助，因为我需要显示通过照片库选择的图像？

Answer 1

强烈建议不要从后台线程更新UI控件。这可能是奇怪的行为和崩溃的原因，有时很难识别。

尝试在主线程上设置图像：

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

    let image = info[UIImagePickerControllerOriginalImage] as? UIImage
    self.imageView.image = image

    dismissViewControllerAnimated(true, completion: nil)
}

Answer 2

我认为此代码可以解决您的问题并使您的照片库中的照片显示出来：

class PostViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {



    @IBOutlet var imageToPost: UIImageView!

    @IBAction func chooseAnImage(_ sender: AnyObject) {

        let imagePicker = UIImagePickerController()

        imagePicker.delegate = self

        imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary

        imagePicker.allowsEditing = false

        self.present(imagePicker, animated: true, completion: nil)

    }

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

        if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {

            imageToPost.image = image


        }

        self.dismiss(animated: true, completion: nil)

    }

Answer 3

在很快的4中，我尝试了各种方法，但是直到我仅向@objc覆盖方法中添加didFinishPickingMediaWithInfo注释后，它们才起作用：

输入UIImagePickerController：

@objc func handleSelectProfileImageView () {
        let pickerController = UIImagePickerController()
        pickerController.delegate = self
        present(pickerController, animated: true, completion: nil)
    }

扩展以获取媒体数据（在这一部分中，我必须添加@objc）：

extension MyViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    @objc func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String: Any]) {
        if let image = info["UIImagePickerControllerOriginalImage"] as? UIImage {
            selectedImage = image
            profileImage.image = image
        }
        dismiss(animated: true, completion: nil)
    }
}

关于@objc from doc：

将此属性应用于可以在其中表示的任何声明 Objective-C-例如，非嵌套类，协议，非泛型枚举（限于整数原始值类型），属性和类，协议和方法的方法（包括获取器和设置器）协议，初始化程序和下标的可选成员。目标属性告诉编译器可以在其中使用声明 Objective-C代码。

UIImageView未显示通过UIIMagePickerController选择的图像

3 个答案: