如何以编程方式拍摄iPhone的屏幕截图？

Question

在目标C中，我们是否可以拍摄屏幕截图并将此图像存储在UIImage中。

Answer 1

The previous code assumes that the view to be captured lives on the main screen...it might not.

Would this work to always capture the content of the main window? (warning: compiled in StackOverflow)

- (UIImage *) captureScreen {
    UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
    CGRect rect = [keyWindow bounds];
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [keyWindow.layer renderInContext:context];   
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return img;
}

Answer 2

You need to create a bitmap context of the size of your screen and use

[self.view.layer renderInContext:c]

to copy your view in it. Once this is done, you can use

CGBitmapContextCreateImage(c)

to create a CGImage from your context.

Elaboration :

CGSize screenSize = [[UIScreen mainScreen] applicationFrame].size;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB(); 
CGContextRef ctx = CGBitmapContextCreate(nil, screenSize.width, screenSize.height, 8, 4*(int)screenSize.width, colorSpaceRef, kCGImageAlphaPremultipliedLast);
CGContextTranslateCTM(ctx, 0.0, screenSize.height);
CGContextScaleCTM(ctx, 1.0, -1.0);

[(CALayer*)self.view.layer renderInContext:ctx];

CGImageRef cgImage = CGBitmapContextCreateImage(ctx);
UIImage *image = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
CGContextRelease(ctx);  
[UIImageJPEGRepresentation(image, 1.0) writeToFile:@"screen.jpg" atomically:NO];

Note that if you run your code in response to a click on a UIButton, your image will shows that button pressed.

Answer 3

Technical Q&A QA1703 Screen Capture in UIKit Applications

http://developer.apple.com/iphone/library/qa/qa2010/qa1703.html

Answer 4

try this...

- (UIImage*)captureView:(UIView *)view 
{
    CGRect rect = [[UIScreen mainScreen] bounds];
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:context];
    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return img;
}

- (void)saveScreenshotToPhotosAlbum:(UIView *)view 
{
    UIImageWriteToSavedPhotosAlbum([self captureView:self.view], nil, nil,nil);
}

Answer 5

UIGraphicsBeginImageContext(self.window.bounds.size);
[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData * data = UIImagePNGRepresentation(image);
[data writeToFile:@"foo.png" atomically:YES];

UPDATE April 2011: for retina display, change the first line into this:

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

Answer 6

- (void)SnapShot {
    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
        UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, [UIScreen mainScreen].scale);
    } else {
        UIGraphicsBeginImageContext(self.view.bounds.size);
    }
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    NSData *data = UIImagePNGRepresentation(image);
    [data writeToFile:@"snapshot.png" options:NSDataWritingWithoutOverwriting error:Nil];
    [data writeToFile:@"snapshot.png" atomically:YES];

    UIImageWriteToSavedPhotosAlbum([UIImage imageWithData:data], nil, nil, nil);
}

Answer 7

// 100% Work

- (UIImage *)screenshot
{                   
  UIGraphicsBeginImageContextWithOptions(self.main_uiview.bounds.size, NO, 2.0f);
  [self.main_uiview drawViewHierarchyInRect:_main_uiview.bounds afterScreenUpdates:YES];

  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  return image;
}

Answer 8

Use this code to take the screenshot:

-(void)webViewDidFinishLoad:(UIWebView *)webView
{
UIGraphicsBeginImageContext(self.webView.bounds.size);

    [self.webView.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *screenshotImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageWriteToSavedPhotosAlbum(screenshotImage, nil, nil, nil);

    NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];


    NSString *str1=[NSString stringWithFormat:@"%d",myInt];

    NSString *pngFilePath = [NSString stringWithFormat:@"%@/page_%@.png",docDir,str1]; // any name u want for image
    NSLog(@"%@",pngFilePath);
    NSData *data1 = [NSData dataWithData:UIImagePNGRepresentation(screenshotImage)]; 
    [data1 writeToFile:pngFilePath atomically:YES];
}

Answer 9

是的，这里是指向苹果开发者论坛的链接https://devforums.apple.com/message/149553

Answer 10

• (UIImage *)screenshot { UIGraphicsBeginImageContextWithOptions(self.main_uiview.bounds.size, NO, 2.0f); [self.main_uiview drawViewHierarchyInRect:_main_uiview.bounds afterScreenUpdates:YES];

  UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();

  return image; }

Answer 11

In modern way:

Obj-C

@interface UIView (Snapshot)
- (UIImage * _Nullable)snapshot;
@end

@implementation UIView (Snapshot)

- (UIImage * _Nullable)snapshot {
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, UIScreen.mainScreen.scale);
    [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

@end

Swift

extension UIView {
    func snapshot() -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.main.scale)
        drawHierarchy(in: bounds, afterScreenUpdates: true)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
   }
}