如何截取 uiview 的屏幕截图并在 swift 中拖动

Question

我得到了代码，但它不起作用，如果我做错了什么，请告诉我。在代码中，我有一个以编程方式创建的图像视图，并将图像添加到 uiview 中。现在我无法在"拖动视图"中加载图像。

func longPressed(_ sender : UILongPressGestureRecognizer){
    let locationInView = sender.location(in: self.view)
    let cell = sender.view as? ParamterCollectionViewCell
    var tImageView: UIImageView!
    tImageView.frame = CGRect(x:0, y:0, width: 30 , height:30)
    tImageView.image = parameterImageArray[0]
    switch sender.state {
    case .began:
        // create an NSData object from myView
        let archive = NSKeyedArchiver.archivedData(withRootObject: tImageView!)
        // create a clone by unarchiving the NSData
       draggingView = NSKeyedUnarchiver.unarchiveObject(with: archive) as? UIView
        self.view.addSubview(draggingView!)
        draggingView!.center = locationInView;
        self.view.bringSubview(toFront: draggingView!)
        break
    case .changed:
        if (contentView.frame.contains(locationInView)) {
            draggingView?.center = locationInView;
        }
        break
    case .ended:
        break
    default:
        break
}

}}

Answer 1

试一试...与您的代码在思想上非常相似，但我认为这可能是一种更好的方法：

func longPressed(_ sender : UILongPressGestureRecognizer) {
    let locationInView: CGPoint = sender.location(in: self.view)
    let locationInCollectionView: CGPoint = sender.location(in: self.collectionView)
    if sender.state == .began {
        if let indexPath: IndexPath = self.collectionView.indexPathForItem(at: locationInCollectionView) {
            if let cell = self.collectionView.cellForItem(at: indexPath) {
                UIGraphicsBeginImageContext(cell.bounds.size)
                cell.layer.render(in: UIGraphicsGetCurrentContext()!)
                let cellImage: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
                UIGraphicsEndImageContext()
                self.movingCellImageView = UIImageView(image: cellImage)
                self.movingCellImageView?.alpha = 0.75
                self.view.addSubview(self.movingCellImageView!)
                self.movingCellImageView?.center = locationInView
            }
        }
    }
    // Move movingCellImageView following finger position
    if sender.state == .changed {
        self.movingCellImageView?.center = locationInView
    }
    // Remove movingCellImageView when ended
    if sender.state == .ended {
        UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseOut, animations: {
            self.movingCellImageView?.alpha = 0
        }, completion: { (success: Bool) in
            self.movingCellImageView?.removeFromSuperview()
            self.movingCellImageView = nil
        })
    }
}

引用：

蒂姆·帕克特 - https://adoptioncurve.net/archives/2014/07/creating-a-draggable-uicollectionviewcell/

陈景康迅速实施http://eatliftswift.weebly.com/technical/creating-a-draggable-uicollectionviewcell