如何在 iOS 中缓存带有图像的整个网页

Question

我正在开发 iOS 上的图像-文本混合页面。我知道我可以使用 UIWebView 来实现目标。但问题是，用户可能需要离线阅读页面。 对于文本部分，我可以将 html 保存到磁盘并以离线模式加载。 但是图像呢？是否可以将图像缓存到磁盘，UIWebView 仍然可以显示它们？

谢谢！

Answer 1

ASIHTTPRequest project 有一个名为ASIWebPageRequest 的类，旨在完全按照您的意愿行事。如果您可以在项目中添加额外的依赖项，那么我认为这对您来说是一个很好的解决方案：ASIWebPageRequest。

在上面我喜欢的页面上，有一些很好的示例说明如何使用它，但为了完整起见，我将在此处包含其中一个示例：

- (IBAction)loadURL:(NSURL *)url
{
   // Assume request is a property of our controller
   // First, we'll cancel any in-progress page load
   [[self request] setDelegate:nil];
   [[self request] cancel];

   [self setRequest:[ASIWebPageRequest requestWithURL:url]];
   [[self request] setDelegate:self];
   [[self request] setDidFailSelector:@selector(webPageFetchFailed:)];
   [[self request] setDidFinishSelector:@selector(webPageFetchSucceeded:)];

   // Tell the request to embed external resources directly in the page
   [[self request] setUrlReplacementMode:ASIReplaceExternalResourcesWithData];

   // It is strongly recommended you use a download cache with ASIWebPageRequest
   // When using a cache, external resources are automatically stored in the cache
   // and can be pulled from the cache on subsequent page loads
   [[self request] setDownloadCache:[ASIDownloadCache sharedCache]];

   // Ask the download cache for a place to store the cached data
   // This is the most efficient way for an ASIWebPageRequest to store a web page
   [[self request] setDownloadDestinationPath:
      [[ASIDownloadCache sharedCache] pathToStoreCachedResponseDataForRequest:[self request]]];

   [[self request] startAsynchronous];
}

- (void)webPageFetchFailed:(ASIHTTPRequest *)theRequest
{
   // Obviously you should handle the error properly...
   NSLog(@"%@",[theRequest error]);
}

- (void)webPageFetchSucceeded:(ASIHTTPRequest *)theRequest
{
   NSString *response = [NSString stringWithContentsOfFile:
      [theRequest downloadDestinationPath] encoding:[theRequest responseEncoding] error:nil];
   // Note we're setting the baseURL to the url of the page we downloaded. This is important!
   [webView loadHTMLString:response baseURL:[request url]];
}