iOS 截屏事件截图

触发截屏事件：

NSOperationQueue *mainQueue = [NSOperationQueue mainQueue];
[[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationUserDidTakeScreenshotNotification
                                            object:nil
                                             queue:mainQueue
                                        usingBlock:^(NSNotification *note) {
                                            // executes after screenshot

                                            NSLog(@"akixie");

                                        }];

截图方法：

- (UIImage *)imageWithScreenshot{

  UIGraphicsBeginImageContextWithOptions(self.view.window.bounds.size, NO, 0);

  [self.view.window drawViewHierarchyInRect:self.view.window.bounds afterScreenUpdates:YES];

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

  return snapshotImage;
}