保存页面的方法

        UIGraphicsBeginImageContextWithOptions(bgView1.bounds.size, YES, 0.0);
        [bgView1.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        [self saveImageToPhotos:img];

- (void)saveImageToPhotos:(UIImage*)savedImage
{
    UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
    //因为需要知道该操作的完成情况，即保存成功与否，所以此处需要一个回调方法image:didFinishSavingWithError:contextInfo:
}
//回调方法
- (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" ;
    }

}