ios - 屏幕突然变白

Question

我正在开发一个项目，我想在图像中添加引号。我设置了我的 Storyboard，效果很好。

现在我添加了向 UICollectionView 添加图像的功能。这也很完美，但由于某种原因，在我启动应用程序时进行一些更改后，仅出现白色屏幕。

你可以看到我的project here on GitHub

如果您不想下载该应用程序，这是我的 NewImagesCollectionViewController 代码:

import UIKit

private let reuseIdentifier = "newImageCell"

class NewImagesCollectionViewController: UICollectionViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

let imagePicker = UIImagePickerController()

var newImageCollection:[UIImage] = []

override func viewWillAppear(animated: Bool) {
    collectionView?.reloadData()
    print(newImageCollection)
}

override func viewDidLoad() {
    super.viewDidLoad()

    imagePicker.delegate = self
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

override func viewWillLayoutSubviews() {
    collectionView?.collectionViewLayout.invalidateLayout()
}

override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return 1
}


override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if newImageCollection.count > 0 {
        return newImageCollection.count
    } else {
        return 0
    }
}

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! NewImagesCollectionViewCell
    cell.newImageView.image = newImageCollection[indexPath.row]
    return cell
}

//MARK: Adding Images
@IBAction func addPicturesPressed(sender: UIBarButtonItem) {
    imagePicker.allowsEditing = false
    imagePicker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
    presentViewController(imagePicker, animated: true, completion: nil)
}

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
    print("didfinishpicking")
    if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
        print("ADD pickedImage!")
        newImageCollection.append(pickedImage)
    }
    dismissViewControllerAnimated(true, completion: nil)
} 
}

Answer 1

您在使用此行时遇到问题:

collectionView?.collectionViewLayout.invalidateLayout()

在您的 viewWillLayoutSubviews 方法中。

只需评论并检查即可。