Swift iOS 中的屏幕截图？

Question

如何通过代码（在 Swift 中）从屏幕上截取屏幕截图并保存？ 我可以截屏并保存为图片吗？

我查看并看到了这段代码，但我不能使用它（我认为），因为它什么也没做。

var screen = UIScreen.mainScreen()
snapshotVieww = screen.snapshotViewAfterScreenUpdates(false)
UIGraphicsBeginImageContextWithOptions(screen.bounds.size, false, 0)
snapshotVieww.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
provino = UIImageView(image: image)

Answer 1

只需这几行代码即可获得视图的屏幕截图：（刚刚测试过）

  UIGraphicsBeginImageContextWithOptions(UIScreen.mainScreen().bounds.size, false, 0);
  self.view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true)
  var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();

  UIGraphicsEndImageContext();

  self.imgView.image = image;

Answer 2

使用 Swift 4 / iOS 10.3，您可以选择以下方法之一来解决您的问题。

---

1。截取视图控制器的视图

以下代码展示了如何截取屏幕截图并将其保存在设备相册中：

import UIKit

class ViewController: UIViewController {

    /* ... */

    @IBAction func screenshot(_ sender: UIBarButtonItem) {
        //Create the UIImage
        UIGraphicsBeginImageContextWithOptions(view.frame.size, true, 0)
        guard let context = UIGraphicsGetCurrentContext() else { return }
        view.layer.render(in: context)
        guard let image = UIGraphicsGetImageFromCurrentImageContext() else { return }
        UIGraphicsEndImageContext()
        
        //Save it to the camera roll
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
    }

}

请注意，此代码的结果将是一个 .JPG 图像。另请注意，导航栏和状态栏不会出现在最终图像中。

从iOS 10开始，作为之前代码的替代，你可以使用下面的代码：

import UIKit

class ViewController: UIViewController {

    /* ... */

    @IBAction func screenshot(_ sender: UIBarButtonItem) {
        //Create the UIImage
        let renderer = UIGraphicsImageRenderer(size: view.frame.size)
        let image = renderer.image(actions: { context in
            view.layer.render(in: context.cgContext)
        })
        
        //Save it to the camera roll
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
    }

}

---

2。截取 iPhone 窗口的屏幕截图

如果要截取包含导航栏（但不包含状态栏）的截图，可以使用以下代码：

import UIKit

class ViewController: UIViewController {

    /* ... */

    @IBAction func screenshot(_ sender: UIBarButtonItem) {
        //Create the UIImage
        guard let layer = UIApplication.shared.keyWindow?.layer else { return }
        UIGraphicsBeginImageContextWithOptions(layer.frame.size, true, 0)
        guard let context = UIGraphicsGetCurrentContext() else { return }
        layer.render(in: context)
        guard let image = UIGraphicsGetImageFromCurrentImageContext() else { return }
        UIGraphicsEndImageContext()
        
        //Save it to the camera roll
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
    }
 
}

从iOS 10开始，作为之前代码的替代，你可以使用下面的代码：

import UIKit

class ViewController: UIViewController {

    /* ... */

    @IBAction func screenshot(_ sender: UIBarButtonItem) {
        //Create the UIImage
        guard let layer = UIApplication.shared.keyWindow?.layer else { return }
        let renderer = UIGraphicsImageRenderer(size: layer.frame.size)
        let image = renderer.image(actions: { context in
            layer.render(in: context.cgContext)
        })
        
        //Save it to the camera roll
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
    }
     
}

---

提醒

从iOS 10开始，为了防止你的应用在调用screenshot(_:)方法时崩溃，你需要在项目的Info.plist文件中添加键NSPhotoLibraryUsageDescription：

<key>NSPhotoLibraryUsageDescription</key>
<string>Some description to explain why access is required</string>

Answer 3

// 脸书或推特上分享的截图就是这样...

func shareButtonClickedToTwitter(){
UIGraphicsBeginImageContextWithOptions(CGSizeMake(320,320), false, 0)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
self.view?.drawViewHierarchyInRect(CGRectMake(-30, -30, self.frame.size.width, self.frame.size.height), afterScreenUpdates: true)
var screenShot  = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.vc.showTWShare("I scored \(score) in Beanystalk can you do better? Available in App Store..", shareImage: screenShot)}


func shareButtonClickedToFaceboook() {
UIGraphicsBeginImageContextWithOptions(CGSizeMake(320,320), false, 0)
var image:UIImage = UIGraphicsGetImageFromCurrentImageContext();
self.view?.drawViewHierarchyInRect(CGRectMake(-30, -30, self.frame.size.width, self.frame.size.height), afterScreenUpdates: true)
var screenShot  = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.vc.showFbShare("I got \(score) Points whilst playing BeanyStalk! Can you beat me?..", shareImageF: screenShot)  }

// facebook分享函数。

    func showFbShare(messageFB: String , shareImageF: UIImage) {
  println(messageFB)
  if SLComposeViewController.isAvailableForServiceType(SLServiceTypeFacebook){
    var fbSheet = SLComposeViewController(forServiceType: SLServiceTypeFacebook)
    fbSheet.completionHandler = {
      result in
      switch result {
      case SLComposeViewControllerResult.Cancelled:
        break
      case SLComposeViewControllerResult.Done:
        break
      }
    }
    fbSheet.addImage(shareImageF)
    fbSheet.setInitialText("\(messageFB) Click here to fun https://hereIsLink/")
    println(messageFB)
    self.presentViewController(fbSheet, animated: false, completion: {
    })
  }
  else {
    var alert = UIAlertController(title: "Accounts", message: "Please login to a facebook account to share.", preferredStyle: UIAlertControllerStyle.Alert)
    alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
    self.presentViewController(alert, animated: true, completion: nil)
  }
}

// 推特分享功能

func showTWShare(message: String , shareImage: UIImage) {
println(message)
if SLComposeViewController.isAvailableForServiceType(SLServiceTypeTwitter){
  var twSheet = SLComposeViewController(forServiceType: SLServiceTypeTwitter)
  twSheet.completionHandler = {
    result in
    switch result {
    case SLComposeViewControllerResult.Cancelled:
      break
    case SLComposeViewControllerResult.Done:
      break
    }
  }
  twSheet.setInitialText("\(message) Click here 2 fun https://hereIsLink/") //The default text in the tweet
  twSheet.addImage(shareImage)
  println(message)
  self.presentViewController(twSheet, animated: false, completion: {
  })
}
else {
  var alert = UIAlertController(title: "Accounts", message: "Please login to a Twitter account to share.", preferredStyle: UIAlertControllerStyle.Alert)
  alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
  self.presentViewController(alert, animated: true, completion: nil)
} }

Answer 4

要截图，Imanou Petit 的回答非常好。我已经在一个扩展中处理了多个版本的 iOS 和 tvOS，并将其作为 pod (pod 'SwiftImageEffects') 提供。

完整代码如下（来自https://github.com/Coeur/ImageEffects/blob/master/SwiftImageEffects/ImageEffects%2Bextensions.swift）：

extension UIView {
    /// Get a UIImage from the UIView
    /// - parameter opaque:
    /// A Boolean flag indicating whether the image is opaque. Specify true to ignore the alpha channel. Specify false to handle any partially transparent pixels.
    /// - parameter scale:
    /// The scale factor to apply to the image. If you specify a value of 0.0, the scale factor is set to the scale factor of the device’s main screen.
    open func renderImage(opaque: Bool = false, scale: CGFloat = 0) -> UIImage {
        if #available(iOS 10.0, tvOS 10.0, *) {
            let format = UIGraphicsImageRendererFormat.default()
            format.opaque = opaque
            format.scale = scale
            return UIGraphicsImageRenderer(size: bounds.size, format: format).image { layer.render(in: $0.cgContext) }
        } else {
            // Fallback on earlier versions
            // The following methods will only return a 8-bit per channel context in the DeviceRGB color space.
            // Any new bitmap drawing code is encouraged to use UIGraphicsImageRenderer in lieu of this API.
            UIGraphicsBeginImageContextWithOptions(bounds.size, opaque, scale)
            defer { UIGraphicsEndImageContext() }
            layer.render(in: UIGraphicsGetCurrentContext()!)
            return UIGraphicsGetImageFromCurrentImageContext()!
        }
    }
}

那么你可以简单的截图如下：

func screenshot() {
    if let image = UIApplication.shared.keyWindow?.renderImage() {
        // saving will require a NSPhotoLibraryUsageDescription in your project's Info.plist
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
    }
}