共享屏幕截图的活动控制器显示为空

Question

我希望我的代码在单击名为共享的按钮时共享屏幕截图。

按钮功能如下：

斯威夫特 3

    func shareBtnAction(_ sender: AnyObject) {

// first I take a screenshot of the drawing    
        UIGraphicsBeginImageContext(drawingAreaView.bounds.size)
        drawingAreaView.image?.draw(in: CGRect(x: 0, y: 0, width: drawingAreaView.frame.size.width, height: drawingAreaView.frame.size.height))

// defining the variable for activityItems  
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

// Initialize and present UIActivityViewController         
        let activity = UIActivityViewController(activityItems: [image], applicationActivities: nil)
        present(activity, animated: true, completion: nil)
    }

结果看起来像这样：

当我用文本字符串替换图像时，我的代码有效

    func shareBtnAction(_ sender: AnyObject) {

// defining the variable for activityItems  
        let text = "This is a test"

// Initialize and present UIActivityViewController         
        let activity = UIActivityViewController(activityItems: [text], applicationActivities: nil)
        present(activity, animated: true, completion: nil)
    }

所以我猜我的代码无法将图像识别为 UIImage。我就是不知道为什么。

Answer 1

我想通了，swift 3 希望你更具体地初始化 UIGraphicsGetImageFromCurrentImageContext 为 UIImage 类型：

let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!

Swift 4 中的或：

let image = UIGraphicsGetImageFromCurrentImageContext() as Any