setPhotoByURLString

- (void)setPhotoByURLString:(NSString *)URLString {
	if (URLString) {
        URLString = [URLString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
        SDImageCache *imageCache = [SDImageCache sharedImageCache];
        [imageCache queryDiskCacheForKey:URLString done:^(UIImage *image, SDImageCacheType cacheType)
        {
            if (image) {
                NSLog(@"image not null!!");
                [self.photoView setImage:image];
            }
            else {
                __weak UIImageView *wphotoView = self.photoView;
                [self.photoView setImageWithURL:[NSURL URLWithString:URLString]
                               placeholderImage:[UIImage imageNamed:@"DefaultPhoto"]
                                      completed:^(UIImage *loadedImage, NSError *error, SDImageCacheType cacheType) {
                                          if (loadedImage) {
                                              wphotoView.image = loadedImage;
                                              [[SDImageCache sharedImageCache] storeImage:loadedImage forKey:URLString];
                                              dispatch_async(dispatch_get_main_queue(), ^{
                                                  wphotoView.image = loadedImage;
                                              });
                                          }
                                      }];
            }
        }];
	} else {
		self.photoView.image = nil;
	}
}