将图片保存到相册

将self.imageView上面的image内容保存到本地相册，并指定判断保存成功与否的方法imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:

- (IBAction)saveImageToAlbum:(id)sender {
    UIImageWriteToSavedPhotosAlbum(self.imageView.image, self, @selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), nil);
}

实现imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:方法

- (void)imageSavedToPhotosAlbum:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    NSString *message = @"呵呵";
    if (!error) {
        message = @"成功保存到相册";
    }else
    {
        message = [error description];
    }
    NSLog(@"message is %@",message);
}