iOS中的截屏（屏幕截屏及scrollView或tableVie

1. 截取屏幕尺寸大小的图片并保存至相册

保存至相册只需将方法saveImage中的代码替换即可

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, YES, 0.0);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

2. scrollView或tableView的全部截屏并保存至相册

- (void)saveImage {
    UIImage* viewImage = nil;
    UITableView *scrollView = self.tableView;
    UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, scrollView.opaque, 0.0);
    {
        CGPoint savedContentOffset = scrollView.contentOffset;
        CGRect savedFrame = scrollView.frame;
        
        scrollView.contentOffset = CGPointZero;
        scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);
        
        [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
        viewImage = UIGraphicsGetImageFromCurrentImageContext();
        
        scrollView.contentOffset = savedContentOffset;
        scrollView.frame = savedFrame;
    }
    UIGraphicsEndImageContext();
    
    [self saveImageToPhotos:viewImage];
}

- (void)saveImageToPhotos:(UIImage*)savedImage {
    UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}

- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo {
    NSString *msg = nil ;
    if(error != NULL){
        msg = @"保存图片失败" ;
    }else{
        msg = @"保存图片成功" ;
    }
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存图片结果提示"
                                                    message:msg
                                                   delegate:self
                                          cancelButtonTitle:@"确定"
                                          otherButtonTitles:nil];
    [alert show];
}