Question

我在父视图上有多个子视图，我需要将uiview转换为uiimage，但只能转换为某些子视图。所以我在视图中添加了一个标签，我需要截取屏幕截图并将其添加到自己的视图中，但是当我尝试截图时，我会看到黑屏。但是，当我使用常规父视图时，我会得到一张包含所有子视图的照片。

let viewPic = UIView()

            for subview in self.view.subviews {

                if(subview.tag == 6) {
                    viewPic.addSubview(subview)
                }

                if(subview.tag == 8) {
                    viewPic.addSubview(subview)
                }
            }

            let picImage = viewPic.getSnapshotImage() //This is a black screen

getSnapshotImage

extension UIView {
    public func getSnapshotImage() -> UIImage {
        UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0)
        self.drawHierarchy(in: self.bounds, afterScreenUpdates: false)
        let snapshotItem: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return snapshotItem
    }
}

Answer 1

首先，您的viewPic没有设置帧大小，因此默认值为零帧，这可能会导致问题。

其次，我尝试在我的示例项目中使用您的getSanpshotImage()，但我总是得到空白图像。

看看演示代码，我可以得到你想要的东西（见截图）：

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        let viewPic = UIView()
        viewPic.frame = self.view.frame

        let view1 = UIView()
        view1.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
        view1.backgroundColor = UIColor.red
        viewPic.addSubview(view1)

        let view2 = UIView()
        view2.frame = CGRect(x: 0, y: 200, width: 100, height: 100)
        view2.backgroundColor = UIColor.blue
        viewPic.addSubview(view2)

        let picImage = viewPic.convertToImage() //This is a black screen
        print(picImage)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}

extension UIView {
    func convertToImage() -> UIImage {
        let renderer = UIGraphicsImageRenderer(bounds: bounds)
        return renderer.image { rendererContext in
            layer.render(in: rendererContext.cgContext)
        }
    }
}

如何在不将其添加到子视图的情况下截取uiview？

1 个答案: