的iOS - 滚动型屏幕截图示出灰色部分

Question

我有以下代码：

func takeScrollScreenshot() -> UIImage? { 

    let scrollview: UIScrollView = self as! UIScrollView 
    UIGraphicsBeginImageContext(scrollview.contentSize) 
    let savedContentOffset = scrollview.contentOffset 
    let savedFrame = scrollview.frame 
    scrollview.contentOffset = CGPoint.zero; 
    scrollview.frame = CGRect(x: CGFloat(0), 
           y: CGFloat(0), 
           width: scrollview.contentSize.width, 
           height: scrollview.contentSize.height); 
    scrollview.layer.render(in: UIGraphicsGetCurrentContext()!) 
    let image = UIGraphicsGetImageFromCurrentImageContext(); 
    scrollview.contentOffset = savedContentOffset 
    scrollview.frame = savedFrame 
    UIGraphicsEndImageContext() 

    return image 
} 

层次结构是这样的：查看 - >滚动型 - >查看 - >剩余的视图

滚动视图的屏幕截图，问题是为什么底部没有着色。

截图内视图。

应该如何看起来像

Answer 1

我找到了解决办法。 我只需要添加一行drawHierarchy(in: self.bounds, afterScreenUpdates: true)

func takeScrollScreenshot() -> UIImage? { 

    let scrollview: UIScrollView = self as! UIScrollView 
    UIGraphicsBeginImageContext(scrollview.contentSize) 
    let savedContentOffset = scrollview.contentOffset 
    let savedFrame = scrollview.frame 
    scrollview.contentOffset = CGPoint.zero; 
    scrollview.frame = CGRect(x: CGFloat(0), 
           y: CGFloat(0), 
           width: scrollview.contentSize.width, 
           height: scrollview.contentSize.height); 
    scrollview.layer.render(in: UIGraphicsGetCurrentContext()!) 

    //I forget add this line. 
    drawHierarchy(in: self.bounds, afterScreenUpdates: true) 

    let image = UIGraphicsGetImageFromCurrentImageContext(); 
    scrollview.contentOffset = savedContentOffset 
    scrollview.frame = savedFrame 
    UIGraphicsEndImageContext() 

    return image 
}