问题
I'm building an app where I need to take a screenshot of a view whose subviews are camera sessions (AVFoundation sessions). I've tried this code:
CGRect rect = [self.containerView bounds];
UIGraphicsBeginImageContextWithOptions(rect.size,YES,0.0f);
CGContextRef context = UIGraphicsGetCurrentContext();
[self.containerView.layer renderInContext:context];
UIImage *capturedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Which effectively gets me an UIImage with the views, only that the camera sessions are black:
I've tried the private method UIGetScreenImage() and works perfectly, but as Apple doesn't allows this, I can't use it. I've also tried the one in Apple's docs but it's the same. I've tracked the problem to AVFoundation sessions using layers. How can I achieve this? The app has a container view with two views which are stopped camera sessions.
回答1:
If using iOS 7, it's fairly simple and you could do something like this from a UIViewController:
UIView *snapshotView = [self.view snapshotViewAfterScreenUpdates:YES];
You can also use this link from a widow: iOS: what's the fastest, most performant way to make a screenshot programatically?
For iOS 6 and earlier, I could only find the following Apple Technical Q&A: [How do I take a screenshot of my app that contains both UIKit and Camera elements?]
- Capture the contents of your camera view.
- Draw that captured camera content yourself into the graphics context that you are rendering your UIKit elements. (Similar to what you did in your code)
回答2:
I too am currently looking for a solution to this problem!
I am currently out at the moment so I can't test what I have found, but take a look at these links:
Screenshots-A Legal Way To Get Screenshots seems like its on the right track - here is the Example Project (and here is the initial post)
When I manage to get it to work I will definitely update this answer!
来源：https://stackoverflow.com/questions/15863588/take-a-screenshot-of-an-uiview-where-its-subviews-are-camera-sessions