Question

我需要缓存进入webview的网络源图像（即不是源代码包）。通常情况下，我只是请求图像并将其转换为base-64并将其粘贴到HTML中，但如果我有100个图像，我就不能那么做。

所以我搜索了一下，找到了通过继承NSURLCache并覆盖cachedResponseForRequest来获取图像请求的方法。我的代码如下。

我能够很好地完成请求，我可以将数据恢复并打印出来，我从数据中创建了一个UIImage并得到它的大小，知道它是definitely等等。但是当我返回cachedResponseForRequest本身，并查看UIWebView时，它只会显示丢失的图像。我一直为此苦苦挣扎一天，无法弄明白。我看过例子之后的例子，没有雪茄。

任何人都可以帮我解决这个问题吗？这让我疯了......

以下是我的NSURLCache子类的.m文件的内容。 GimageData是用于存储接收的当前图像数据的实例变量。

就是你知道，为什么我搜索/替换http___到http：//的原因是http：//链接显然不会被这个方法拿起来，所以我让链接看起来像它的在捆绑中的东西然后我还原URL以供检索。

- (NSCachedURLResponse*)cachedResponseForRequest:(NSURLRequest*)request
{
    NSURL *url = [request URL];

 NSLog(@"Url requested is: %@", [url absoluteString] );


 NSRange textRange;

 textRange = [[[url absoluteString] lowercaseString] rangeOfString:[@"http___" lowercaseString]];
 NSCachedURLResponse *cachedResponse = nil;

 if(textRange.location != NSNotFound) {

  //Does contain the substring
  NSLog(@"Found an http___ request");
  NSString *newURL = [[url absoluteString] substringFromIndex:textRange.location];
  newURL = [newURL stringByReplacingOccurrencesOfString:@"http___" withString:@"http://"];
  NSLog(@"New url: %@", newURL);

  TTURLDataResponse *response = [[TTURLDataResponse alloc] init];
  TTURLRequest *imageRequest = [[TTURLRequest alloc] initWithURL:newURL
                 delegate:self];
  imageRequest.response = response;
  [response release];
  [imageRequest sendSynchronously];


  if ( GimageData ) {
   NSLog(@"Response: %d as %@", [GimageData bytes], [GimageData class]);
   NSLog(@"Storing under: %@ ", request.URL );

   NSURLResponse* Nresponse = [[NSURLResponse alloc] initWithURL:request.URL 
                 MIMEType:nil 
             expectedContentLength:[GimageData length] 
               textEncodingName:nil];

   cachedResponse = [[NSCachedURLResponse alloc] initWithResponse:Nresponse
                   data:GimageData];

   [imageRequest release];
   [Nresponse release];
   NSLog(@"Cached the response.");
  }

 }

 if (cachedResponse == nil) {
  NSLog(@"Response is nil so getting super's cache");
  cachedResponse = [super cachedResponseForRequest:request];
 }

    return cachedResponse;
}


- (void)requestDidFinishLoad:(TTURLRequest*)request {
 NSLog(@"Request did finish loading.");

 TTURLDataResponse *response = request.response;
// NSURL *url = [NSURL URLWithString:request.urlPath];

 GimageData = response.data;


 if ( GimageData ) {
  NSLog(@"And we got the data.");
 }
 else {
  NSLog(@"But there was no data in the response.");
 }

}

覆盖NSURLCache的cachedResponseForRequest以使用Three20缓存UIWebView资产

0 个答案: