ios - UIImageView 未正确初始化并返回 nil

Question

在我的 CathyTaskLogMessageViewController 类中，我有这段代码:

import UIKit

class CathyTaskLogMessageViewController: UIViewController {

    @IBOutlet var tapGestureRecognizer: UITapGestureRecognizer!
    @IBOutlet weak var messageTextView: UITextView!
    var defaultPictureButton: UIButton = UIButton(type: UIButtonType.Custom) as UIButton

    override func viewDidLoad() {
        super.viewDidLoad()

        defaultPictureButton = UIButton(type: UIButtonType.Custom) as UIButton
        defaultPictureButton.frame = CGRectMake(100, 100, 40, 40)
        defaultPictureButton.addTarget(self, action: "defaultPictureButtonTapped:", forControlEvents: UIControlEvents.TouchUpInside)
        defaultPictureButton.setImage(UIImage(named: "defaultPicture"), forState: UIControlState.Normal)
        defaultPictureButton.layer.cornerRadius = 20.0
        defaultPictureButton.clipsToBounds = true
        defaultPictureButton.exclusiveTouch = true
        self.view.addSubview(defaultPictureButton)

    }

    func defaultPictureButtonTapped(sender: UIButton) {

        let imageViewerViewController = ImageViewerViewController()
        imageViewerViewController.image = self.defaultPictureButton.imageView!.image
        imageViewerViewController.centerPictureFromPoint(self.defaultPictureButton.frame.origin, ofSize: self.defaultPictureButton.frame.size, withCornerRadius: self.defaultPictureButton.layer.cornerRadius)

    }

}

在我的 ImageViewerViewController 类中，我有以下代码:

import UIKit

class ImageViewerViewController: UIViewController, UIScrollViewDelegate {

    @IBOutlet weak var image: UIImage!
    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var scrollView: UIScrollView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    func centerPictureFromPoint(point: CGPoint, ofSize size: CGSize, withCornerRadius radius: CGFloat) {

        self.imageView = UIImageView(frame: CGRect(x: point.x, y: point.y, width: size.width, height: size.height))
        self.imageView.layer.cornerRadius = radius //I am getting the error here
        self.imageView.clipsToBounds = true
        self.imageView.image = self.image

    }

}

我得到的错误是:fatal error: unwrappedly found nil while unwrapping an Optional value。在我看来，我通过编写 self.imageView = UIImageView(frame: CGRect(x: point.x, y: point.y, width: size.width, height:尺寸.高度))。但是，它返回零。有人对此有解决方案吗？

Answer 1

如果您不想通过 xib 或 Storyboard启动 imageView。更改属性声明:

@IBOutlet weak var imageView: UIImageView!

到

var imageView: UIImageView!

weak 导致 imageView 立即释放。