// 防止多次调用
#define kPreventRepeatClickTime(_seconds_) \
static BOOL shouldPrevent; \
if (shouldPrevent) return; \
shouldPrevent = YES; \
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)((_seconds_) * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ \
shouldPrevent = NO; \
}); \

kPreventRepeatClickTime(0.5);

+ (UIViewController *)currentViewController {
 UIWindow * window = [[UIApplication sharedApplication] keyWindow];
 if (window.windowLevel != UIWindowLevelNormal){
  NSArray *windows = [[UIApplication sharedApplication] windows];
  for(UIWindow * tmpWin in windows){
   if (tmpWin.windowLevel == UIWindowLevelNormal){
    window = tmpWin;
    break;
   }
  }
 }
 UIViewController *currentVC = window.rootViewController;
 while (currentVC.presentedViewController) {
  currentVC = currentVC.presentedViewController;
 }
 if ([currentVC isKindOfClass:[UITabBarController class]]) {
  currentVC = [(UITabBarController *)currentVC selectedViewController];
 }
 if ([currentVC isKindOfClass:[UINavigationController class]]) {
  currentVC = [(UINavigationController *)currentVC topViewController];
 }
 return currentVC;
}

/// 截屏
- (void)actionForScreenShotWith:(UIView *)aimView savePhoto:(BOOL)savePhoto {

 if (!aimView) return;

 UIGraphicsBeginImageContextWithOptions(aimView.bounds.size, NO, 0.0f);
 [aimView.layer renderInContext: UIGraphicsGetCurrentContext()];
 UIImage* viewImage = UIGraphicsGetImageFromCurrentImageContext();

 UIGraphicsEndImageContext();

 if (savePhoto) {
  /// 保存到本地相册
  UIImageWriteToSavedPhotosAlbum(viewImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
 }
}

- (void)image:(UIImage*)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo{
 if (error) {
  NSLog(@"保存失败，请重试");
 } else {
  NSLog(@"保存成功");
 }
}