Capturing full screenshot with status bar in iOS p

问题:

I am using this code to capture a screenshot and to save it to the photo album.

-(void)TakeScreenshotAndSaveToPhotoAlbum
{
   UIWindow *window = [UIApplication sharedApplication].keyWindow;

   if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
       UIGraphicsBeginImageContextWithOptions(window.bounds.size, NO, [UIScreen mainScreen].scale);
   else
       UIGraphicsBeginImageContext(window.bounds.size);

   [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
   UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();

   UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
}

But the problem is whenever the screenshot is saved, I see the status bar of iPhone is not captured. Instead a white space appears at the bottom. Like the following image:

What am I doing wrong?

回答1:

The status bar is actually in its own UIWindow, in your code you are only rendering the view of your viewcontroller which does not include this.

The "official" screenshot method was here but now seems to have been removed by Apple, probably due to it being obsolete.

Under iOS 7 there is now a new method on UIScreen for getting a view holding the contents of the entire screen:

- (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates

This will give you a view which you can then manipulate on screen for various visual effects.

If you want to draw the view hierarchy into a context, you need to iterate through the windows of the application ([[UIApplication sharedApplication] windows]) and call this method on each one:

- (BOOL)drawViewHierarchyInRect:(CGRect)rect afterScreenUpdates:(BOOL)afterUpdates

You may be able to combine the two above approaches and take the snapshot view, then use the above method on the snapshot to draw it.

回答2:

The suggested "official" screenshot method doesn't capture status bar (it is not in the windows list of the application). As tested on iOS 5.

I believe, this is for security reasons, but there is no mention of it in the docs.

I suggest two options:

• draw a stub status bar image from resources of your app (optionally update time indicator);
• capture only your view, without status bar, or trim image afterwards (image size will differ from standard device resolution); status bar frame is known from corresponding property of application object.

回答3:

Here is my code to take a screenshot and store it as NSData (inside an IBAction). With the sotred NSData then you can share or email or whatever want to do

CGSize imageSize = [[UIScreen mainScreen] bounds].size;
        if (NULL != UIGraphicsBeginImageContextWithOptions)
            UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
        else
            UIGraphicsBeginImageContext(imageSize);

        CGContextRef context = UIGraphicsGetCurrentContext();

        // Iterate over every window from back to front
        for (UIWindow *window in [[UIApplication sharedApplication] windows])
        {
            if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen])
            {
                // -renderInContext: renders in the coordinate space of the layer,
                // so we must first apply the layer's geometry to the graphics context
                CGContextSaveGState(context);
                // Center the context around the window's anchor point
                CGContextTranslateCTM(context, [window center].x, [window center].y);
                // Apply the window's transform about the anchor point
                CGContextConcatCTM(context, [window transform]);
                // Offset by the portion of the bounds left of and above the anchor point
                CGContextTranslateCTM(context,
                                      -[window bounds].size.width * [[window layer] anchorPoint].x,
                                      -[window bounds].size.height * [[window layer] anchorPoint].y);

                // Render the layer hierarchy to the current context
                [[window layer] renderInContext:context];

                // Restore the context
                CGContextRestoreGState(context);
            }
        }

        // Retrieve the screenshot image
        UIImage *imageForEmail = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

    NSData *imageDataForEmail = UIImageJPEGRepresentation(imageForEmail, 1.0);

回答4:

Answer of above question for Objective-C is already write there, here is the Swift version answer of above question.

For Swift 3+

Take screenshot and then use it to display somewhere or to send over web.

extension UIImage {
    class var screenShot: UIImage? {
        let imageSize = UIScreen.main.bounds.size as CGSize;
        UIGraphicsBeginImageContextWithOptions(imageSize, false, 0)
        guard let context = UIGraphicsGetCurrentContext() else {return nil}
        for obj : AnyObject in UIApplication.shared.windows {
            if let window = obj as? UIWindow {
                if window.responds(to: #selector(getter: UIWindow.screen)) || window.screen == UIScreen.main {
                    // so we must first apply the layer's geometry to the graphics context
                    context.saveGState();
                    // Center the context around the window's anchor point
                    context.translateBy(x: window.center.x, y: window.center
                        .y);
                    // Apply the window's transform about the anchor point
                    context.concatenate(window.transform);
                    // Offset by the portion of the bounds left of and above the anchor point
                    context.translateBy(x: -window.bounds.size.width * window.layer.anchorPoint.x,
                                         y: -window.bounds.size.height * window.layer.anchorPoint.y);

                    // Render the layer hierarchy to the current context
                    window.layer.render(in: context)

                    // Restore the context
                    context.restoreGState();
                }
            }
        }
        guard let image = UIGraphicsGetImageFromCurrentImageContext() else {return nil}
        return image
    }
}

Usage of above screenshot

• Lets display above screen shot on UIImageView

  yourImageView = UIImage.screenShot
  

• Get image Data to save/send over web

  if let img = UIImage.screenShot {
      if let data = UIImagePNGRepresentation(img) {
          //send this data over web or store it anywhere
      }
  }
  

回答5:

The following works for me, capturing the status bar fine (iOS 9, Swift)

let screen = UIScreen.mainScreen()
let snapshotView = screen.snapshotViewAfterScreenUpdates(true)
UIGraphicsBeginImageContextWithOptions(snapshotView.bounds.size, true, 0)
snapshotView.drawViewHierarchyInRect(snapshotView.bounds, afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()