UIImagePickerController 从 UICollectionViewCell 内的 UIImageView 呈现

Question

我在从 UIImageView 中的 UIImagePickerController 加载选定图像时遇到问题。 UIImageView 通过点击 collectionViewCell 中的按钮呈现。在 collectionViewCell 中点击该按钮时，UIImageView 会以动画形式显示在视图中。在点击该 UIImageView 时，会显示 uiimagepicker。选择图像时，选择器会很好地关闭，但图像不会在选择器关闭时加载到 uiimageView 内（占位符图像仍然存在并且不会被所选图像替换）。我的控制台中没有发生崩溃或错误。感谢您的帮助！

UICollectionViewCell 类 - LoginCell

class LoginCell: UICollectionViewCell, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

lazy var createUsernameButton: UIButton = {
    let customButton = UIButton(type: .system)
    customButton.setTitle("Create Username", for: .normal)
    customButton.addTarget(self, action: #selector(animateIn), for: .touchUpInside)
    return customButton
}()

func animateIn() {
    addSubview(profileImageView)

    profileImageView.transform = CGAffineTransform.init(scaleX: 1.3, y: 1.3)
    profileImageView.alpha = 0

    UIView.animate(withDuration: 0.2) {
        self.profileImageView.alpha = 1
        self.profileImageView.transform = CGAffineTransform.identity
    }

}

    lazy var profileImageView: UIImageView = {
        let imageView = UIImageView()
        imageView.image = UIImage(named: "avatar-bg-2x")
        imageView.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(handleSelectProfileImage)))
        imageView.isUserInteractionEnabled = true
        return imageView
    }()

    var loginController: LoginController?

    func handleSelectProfileImage() {
        guard let loginController = delegate as? LoginController else {
            return
        }
        loginController.showImagePicker()
    }

//.....
}

loginController 类

class LoginController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, LoginControllerDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    weak var loginCollectionView: UICollectionView!
    var loginCell: LoginCell?

    func showImagePicker() {
        let picker = UIImagePickerController()
        picker.delegate = self
        picker.allowsEditing = true
        present(picker, animated: true, completion: nil)
    }

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

        var selectedImageFromImagePicker: UIImage?

        if let editedImage = info["UIImagePickerControllerEditedImage"] as? UIImage {
            selectedImageFromImagePicker = editedImage
        } else if let originalImage = info["UIImagePickerControllerOriginalImage"] as? UIImage {
            selectedImageFromImagePicker = originalImage
        }

        dismiss(animated: true, completion: {
            if let selectedImage = selectedImageFromImagePicker {
                self.loginCell?.profileImageView.image = selectedImage
                print("was dismissed")
            }
        })
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let loginCell = collectionView.dequeueReusableCell(withReuseIdentifier: loginCellId, for: indexPath) as! LoginCell
            loginCell.delegate = self
            return loginCell
    }
// ...
}

Answer 1

我发现了问题，你没有在主线程上更新图像。试试这个：

1.更改登录控制器类中的代码以匹配以下代码。

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

    var selectedImageFromImagePicker: UIImage?

    if let editedImage = info["UIImagePickerControllerEditedImage"] as? UIImage {
        selectedImageFromImagePicker = editedImage
    } else if let originalImage = info["UIImagePickerControllerOriginalImage"] as? UIImage {
        selectedImageFromImagePicker = originalImage
    }

    if let selectedImage = selectedImageFromImagePicker {
        DispatchQueue.main.async {
            self.loginCell?.profileImageView.image = selectedImage
            self.loginCollectionView.reloadData() //EDIT: add this new piece of code
        }
    }

    dismiss(animated: true, completion: nil)
}

var profileImage: UIImage?

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let loginCell = collectionView.dequeueReusableCell(withReuseIdentifier: loginCellId, for: indexPath) as! LoginCell
        loginCell.delegate = self
        loginCell.profileImageView.image = profileImage != nil ? profileImage : UIImage(named: "avatar-bg-2x")
        return loginCell
}

2.在您的 loginCell 类中更改此代码以匹配以下代码。

lazy var profileImageView: UIImageView = {
    let imageView = UIImageView()
    //removed line here
    imageView.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(handleSelectProfileImage)))
    imageView.isUserInteractionEnabled = true
    return imageView
}()