iOS 11没有从MKMapView抓取屏幕

Question

我有一个应用程序显示用户在MKMapView上走过的位置。当用户离开地图视图时，应用程序抓住屏幕并将图像保存在磁盘上。直到iOSS 10.3这种方法总是成功的。使用iOS 11.0时，屏幕抓图是空白图像。我没有收到来自xcode的通知，说有一些变化，我需要调整代码。

有趣的是，文本页面的抓取仍然抓取并保存成功。

有没有人遇到同样的问题，并得到了解决办法？

的代码一直是成功的，不外现在是：

override func viewWillDisappear(_ animated: Bool) { 

    //Set the full file name under which the track will be saved. 
    let fileBaseName = self.imageName.appending(String(describing: (self.display?.trackDate)!)) 
    let fileFullName = fileBaseName.appending(".png") 

    //Check if the image already has been saved 
    if !AuxiliaryObjects.shared.getImageFileName(with: fileFullName) { 

     //Create the sizes of the capture 
     let screenRect = self.trackMapView.frame 
     let screenSize = screenRect.size 
     let screenScale = UIScreen.main.scale 
     var grabRect = self.trackMapView.convertRegion(self.mapRegion, toRectTo: self.view) 
     var heightAdjustment : CGFloat = 0.0 

     //Grab the image from the screen 
     UIGraphicsBeginImageContextWithOptions(screenSize, false, screenScale) 
     self.trackMapView.drawHierarchy(in: screenRect, afterScreenUpdates: true) 
     let myImage = UIGraphicsGetImageFromCurrentImageContext() 

     grabRect.origin.x *= (myImage?.scale)! 
     grabRect.origin.y *= (myImage?.scale)! 
     grabRect.size.width *= (myImage?.scale)! 
     grabRect.size.height *= (myImage?.scale)! 
     let grabImage = (myImage?.cgImage)!.cropping(to: grabRect) 
     let mapImage = UIImage(cgImage: grabImage!) 

     UIGraphicsEndImageContext() 

     AuxiliaryObjects.shared.save(image: mapImage, with: fileFullName, and: self.imageName) 
     self.display?.displayImage = AuxiliaryObjects.shared.getImage(with: fileFullName, with: self.tableImageRect)! 
    } else { 
     self.display?.displayImage = AuxiliaryObjects.shared.getImage(with: fileFullName, with: self.tableImageRect)! 
    } 
} 

Answer 1

我提交了代码级的支持请求在苹果公司得到答案的问题。 Apple不支持使用drawHierarhy来抓取MapKit屏幕。要走的路是使用MKMapSnapshotter实用程序创建MKMapSnapshot，然后通过将所有地图坐标转换为视图坐标来绘制线条和注释。

由于这给我一些获得镜像和正确翻译坐标的问题，我决定使用图层方法渲染（在：CGContext），这为我提供了一个运行良好的非常高效的屏幕抓取。

func creatSnapshot(with fileName: String) { 

    UIGraphicsBeginImageContextWithOptions(self.trackMapView.frame.size, false, UIScreen.main.scale) 
    let currentContext = UIGraphicsGetCurrentContext() 
    self.trackMapView.layer.render(in: currentContext!) 

    let contextImage = (UIGraphicsGetImageFromCurrentImageContext())! 
    UIGraphicsEndImageContext() 

    let region = self.trackMapView.region 
    var cropRect = self.trackMapView.convertRegion(region, toRectTo: self.trackMapView.superview) 

    cropRect.origin.x *= contextImage.scale 
    cropRect.origin.y *= contextImage.scale 
    cropRect.size.height *= contextImage.scale 
    cropRect.size.width *= contextImage.scale 

    let cgMapImage = contextImage.cgImage?.cropping(to: cropRect) 
    let mapImage = UIImage(cgImage: cgMapImage!) 

    AuxiliaryObjects.shared.save(image: mapImage, with: fileName, and: self.imageName) 
    self.displayTrack?.displayImage = AuxiliaryObjects.shared.getImage(with: fileName, with: self.tableImageRect)! 
    NotificationCenter.default.post(name: self.imageSavedNotification, object: self) 
}