循环调用方法，已达到保存全部图片的效果

-(void)downImage:(UIButton*)sender{
    for(UIView *subview in [imgCollectoin subviews]){
        NSLog(@"subview=%@",subview);
        if([subview isKindOfClass:[UIButton class]]){
            UIButton* imgView = (UIButton*)subview;
            [imgArray addObject:imgView.imageView.image];
            NSLog(@"%@",imgView.imageView.image);
        }
    }
    [UIView dd_showMessage:@"图片保存成功"];
    [self saveNextPhoto];
}
-(void)saveNextPhoto{
    if(imgArray.count>0){
        UIImage *image=[imgArray objectAtIndex:0];
        UIImageWriteToSavedPhotosAlbum(image, self, @selector(savedPhotoImage:didFinishSavingWithError:contextInfo:), nil);
    }else{
    }
}
-(void)savedPhotoImage:(UIImage*)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{
    if(error){
    }else{
        [imgArray removeObjectAtIndex:0];
    }
    [self saveNextPhoto];
}